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|
/*
* brin_minmax_multi.c
* Implementation of Multi Min/Max opclass for BRIN
*
* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* Implements a variant of minmax opclass, where the summary is composed of
* multiple smaller intervals. This allows us to handle outliers, which
* usually make the simple minmax opclass inefficient.
*
* Consider for example page range with simple minmax interval [1000,2000],
* and assume a new row gets inserted into the range with value 1000000.
* Due to that the interval gets [1000,1000000]. I.e. the minmax interval
* got 1000x wider and won't be useful to eliminate scan keys between 2001
* and 1000000.
*
* With minmax-multi opclass, we may have [1000,2000] interval initially,
* but after adding the new row we start tracking it as two interval:
*
* [1000,2000] and [1000000,1000000]
*
* This allows us to still eliminate the page range when the scan keys hit
* the gap between 2000 and 1000000, making it useful in cases when the
* simple minmax opclass gets inefficient.
*
* The number of intervals tracked per page range is somewhat flexible.
* What is restricted is the number of values per page range, and the limit
* is currently 32 (see values_per_range reloption). Collapsed intervals
* (with equal minimum and maximum value) are stored as a single value,
* while regular intervals require two values.
*
* When the number of values gets too high (by adding new values to the
* summary), we merge some of the intervals to free space for more values.
* This is done in a greedy way - we simply pick the two closest intervals,
* merge them, and repeat this until the number of values to store gets
* sufficiently low (below 50% of maximum values), but that is mostly
* arbitrary threshold and may be changed easily).
*
* To pick the closest intervals we use the "distance" support procedure,
* which measures space between two ranges (i.e. the length of an interval).
* The computed value may be an approximation - in the worst case we will
* merge two ranges that are slightly less optimal at that step, but the
* index should still produce correct results.
*
* The compactions (reducing the number of values) is fairly expensive, as
* it requires calling the distance functions, sorting etc. So when building
* the summary, we use a significantly larger buffer, and only enforce the
* exact limit at the very end. This improves performance, and it also helps
* with building better ranges (due to the greedy approach).
*
*
* IDENTIFICATION
* src/backend/access/brin/brin_minmax_multi.c
*/
#include "postgres.h"
/* needed for PGSQL_AF_INET */
#include <sys/socket.h>
#include "access/genam.h"
#include "access/brin.h"
#include "access/brin_internal.h"
#include "access/brin_tuple.h"
#include "access/reloptions.h"
#include "access/stratnum.h"
#include "access/htup_details.h"
#include "catalog/pg_type.h"
#include "catalog/pg_am.h"
#include "catalog/pg_amop.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/date.h"
#include "utils/datum.h"
#include "utils/float.h"
#include "utils/inet.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/numeric.h"
#include "utils/pg_lsn.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#include "utils/timestamp.h"
#include "utils/uuid.h"
/*
* Additional SQL level support functions
*
* Procedure numbers must not use values reserved for BRIN itself; see
* brin_internal.h.
*/
#define MINMAX_MAX_PROCNUMS 1 /* maximum support procs we need */
#define PROCNUM_DISTANCE 11 /* required, distance between values */
/*
* Subtract this from procnum to obtain index in MinmaxMultiOpaque arrays
* (Must be equal to minimum of private procnums).
*/
#define PROCNUM_BASE 11
/*
* Sizing the insert buffer - we use 10x the number of values specified
* in the reloption, but we cap it to 8192 not to get too large. When
* the buffer gets full, we reduce the number of values by half.
*/
#define MINMAX_BUFFER_FACTOR 10
#define MINMAX_BUFFER_MIN 256
#define MINMAX_BUFFER_MAX 8192
#define MINMAX_BUFFER_LOAD_FACTOR 0.5
typedef struct MinmaxMultiOpaque
{
FmgrInfo extra_procinfos[MINMAX_MAX_PROCNUMS];
bool extra_proc_missing[MINMAX_MAX_PROCNUMS];
Oid cached_subtype;
FmgrInfo strategy_procinfos[BTMaxStrategyNumber];
} MinmaxMultiOpaque;
/*
* Storage type for BRIN's minmax reloptions
*/
typedef struct MinMaxMultiOptions
{
int32 vl_len_; /* varlena header (do not touch directly!) */
int valuesPerRange; /* number of values per range */
} MinMaxMultiOptions;
#define MINMAX_MULTI_DEFAULT_VALUES_PER_PAGE 32
#define MinMaxMultiGetValuesPerRange(opts) \
((opts) && (((MinMaxMultiOptions *) (opts))->valuesPerRange != 0) ? \
((MinMaxMultiOptions *) (opts))->valuesPerRange : \
MINMAX_MULTI_DEFAULT_VALUES_PER_PAGE)
#define SAMESIGN(a,b) (((a) < 0) == ((b) < 0))
/*
* The summary of minmax-multi indexes has two representations - Ranges for
* convenient processing, and SerializedRanges for storage in bytea value.
*
* The Ranges struct stores the boundary values in a single array, but we
* treat regular and single-point ranges differently to save space. For
* regular ranges (with different boundary values) we have to store both
* values, while for "single-point ranges" we only need to save one value.
*
* The 'values' array stores boundary values for regular ranges first (there
* are 2*nranges values to store), and then the nvalues boundary values for
* single-point ranges. That is, we have (2*nranges + nvalues) boundary
* values in the array.
*
* +---------------------------------+-------------------------------+
* | ranges (sorted pairs of values) | sorted values (single points) |
* +---------------------------------+-------------------------------+
*
* This allows us to quickly add new values, and store outliers without
* making the other ranges very wide.
*
* We never store more than maxvalues values (as set by values_per_range
* reloption). If needed we merge some of the ranges.
*
* To minimize palloc overhead, we always allocate the full array with
* space for maxvalues elements. This should be fine as long as the
* maxvalues is reasonably small (64 seems fine), which is the case
* thanks to values_per_range reloption being limited to 256.
*/
typedef struct Ranges
{
/* Cache information that we need quite often. */
Oid typid;
Oid colloid;
AttrNumber attno;
FmgrInfo *cmp;
/* (2*nranges + nvalues) <= maxvalues */
int nranges; /* number of ranges in the array (stored) */
int nsorted; /* number of sorted values (ranges + points) */
int nvalues; /* number of values in the data array (all) */
int maxvalues; /* maximum number of values (reloption) */
/*
* We simply add the values into a large buffer, without any expensive
* steps (sorting, deduplication, ...). The buffer is a multiple of the
* target number of values, so the compaction happens less often,
* amortizing the costs. We keep the actual target and compact to the
* requested number of values at the very end, before serializing to
* on-disk representation.
*/
/* requested number of values */
int target_maxvalues;
/* values stored for this range - either raw values, or ranges */
Datum values[FLEXIBLE_ARRAY_MEMBER];
} Ranges;
/*
* On-disk the summary is stored as a bytea value, with a simple header
* with basic metadata, followed by the boundary values. It has a varlena
* header, so can be treated as varlena directly.
*
* See brin_range_serialize/brin_range_deserialize for serialization details.
*/
typedef struct SerializedRanges
{
/* varlena header (do not touch directly!) */
int32 vl_len_;
/* type of values stored in the data array */
Oid typid;
/* (2*nranges + nvalues) <= maxvalues */
int nranges; /* number of ranges in the array (stored) */
int nvalues; /* number of values in the data array (all) */
int maxvalues; /* maximum number of values (reloption) */
/* contains the actual data */
char data[FLEXIBLE_ARRAY_MEMBER];
} SerializedRanges;
static SerializedRanges *brin_range_serialize(Ranges *range);
static Ranges *brin_range_deserialize(int maxvalues, SerializedRanges *range);
/*
* Used to represent ranges expanded to make merging and combining easier.
*
* Each expanded range is essentially an interval, represented by min/max
* values, along with a flag whether it's a collapsed range (in which case
* the min and max values are equal). We have the flag to handle by-ref
* data types - we can't simply compare the datums, and this saves some
* calls to the type-specific comparator function.
*/
typedef struct ExpandedRange
{
Datum minval; /* lower boundary */
Datum maxval; /* upper boundary */
bool collapsed; /* true if minval==maxval */
} ExpandedRange;
/*
* Represents a distance between two ranges (identified by index into
* an array of extended ranges).
*/
typedef struct DistanceValue
{
int index;
double value;
} DistanceValue;
/* Cache for support and strategy procedures. */
static FmgrInfo *minmax_multi_get_procinfo(BrinDesc *bdesc, uint16 attno,
uint16 procnum);
static FmgrInfo *minmax_multi_get_strategy_procinfo(BrinDesc *bdesc,
uint16 attno, Oid subtype,
uint16 strategynum);
typedef struct compare_context
{
FmgrInfo *cmpFn;
Oid colloid;
} compare_context;
static int compare_values(const void *a, const void *b, void *arg);
#ifdef USE_ASSERT_CHECKING
/*
* Check that the order of the array values is correct, using the cmp
* function (which should be BTLessStrategyNumber).
*/
static void
AssertArrayOrder(FmgrInfo *cmp, Oid colloid, Datum *values, int nvalues)
{
int i;
Datum lt;
for (i = 0; i < (nvalues - 1); i++)
{
lt = FunctionCall2Coll(cmp, colloid, values[i], values[i + 1]);
Assert(DatumGetBool(lt));
}
}
#endif
/*
* Comprehensive check of the Ranges structure.
*/
static void
AssertCheckRanges(Ranges *ranges, FmgrInfo *cmpFn, Oid colloid)
{
#ifdef USE_ASSERT_CHECKING
int i;
/* some basic sanity checks */
Assert(ranges->nranges >= 0);
Assert(ranges->nsorted >= 0);
Assert(ranges->nvalues >= ranges->nsorted);
Assert(ranges->maxvalues >= 2 * ranges->nranges + ranges->nvalues);
Assert(ranges->typid != InvalidOid);
/*
* First the ranges - there are 2*nranges boundary values, and the values
* have to be strictly ordered (equal values would mean the range is
* collapsed, and should be stored as a point). This also guarantees that
* the ranges do not overlap.
*/
AssertArrayOrder(cmpFn, colloid, ranges->values, 2 * ranges->nranges);
/* then the single-point ranges (with nvalues boundary values ) */
AssertArrayOrder(cmpFn, colloid, &ranges->values[2 * ranges->nranges],
ranges->nsorted);
/*
* Check that none of the values are not covered by ranges (both sorted
* and unsorted)
*/
for (i = 0; i < ranges->nvalues; i++)
{
Datum compar;
int start,
end;
Datum minvalue,
maxvalue;
Datum value = ranges->values[2 * ranges->nranges + i];
if (ranges->nranges == 0)
break;
minvalue = ranges->values[0];
maxvalue = ranges->values[2 * ranges->nranges - 1];
/*
* Is the value smaller than the minval? If yes, we'll recurse to the
* left side of range array.
*/
compar = FunctionCall2Coll(cmpFn, colloid, value, minvalue);
/* smaller than the smallest value in the first range */
if (DatumGetBool(compar))
continue;
/*
* Is the value greater than the maxval? If yes, we'll recurse to the
* right side of range array.
*/
compar = FunctionCall2Coll(cmpFn, colloid, maxvalue, value);
/* larger than the largest value in the last range */
if (DatumGetBool(compar))
continue;
start = 0; /* first range */
end = ranges->nranges - 1; /* last range */
while (true)
{
int midpoint = (start + end) / 2;
/* this means we ran out of ranges in the last step */
if (start > end)
break;
/* copy the min/max values from the ranges */
minvalue = ranges->values[2 * midpoint];
maxvalue = ranges->values[2 * midpoint + 1];
/*
* Is the value smaller than the minval? If yes, we'll recurse to
* the left side of range array.
*/
compar = FunctionCall2Coll(cmpFn, colloid, value, minvalue);
/* smaller than the smallest value in this range */
if (DatumGetBool(compar))
{
end = (midpoint - 1);
continue;
}
/*
* Is the value greater than the minval? If yes, we'll recurse to
* the right side of range array.
*/
compar = FunctionCall2Coll(cmpFn, colloid, maxvalue, value);
/* larger than the largest value in this range */
if (DatumGetBool(compar))
{
start = (midpoint + 1);
continue;
}
/* hey, we found a matching range */
Assert(false);
}
}
/* and values in the unsorted part must not be in sorted part */
for (i = ranges->nsorted; i < ranges->nvalues; i++)
{
compare_context cxt;
Datum value = ranges->values[2 * ranges->nranges + i];
if (ranges->nsorted == 0)
break;
cxt.colloid = ranges->colloid;
cxt.cmpFn = ranges->cmp;
Assert(bsearch_arg(&value, &ranges->values[2 * ranges->nranges],
ranges->nsorted, sizeof(Datum),
compare_values, (void *) &cxt) == NULL);
}
#endif
}
/*
* Check that the expanded ranges (built when reducing the number of ranges
* by combining some of them) are correctly sorted and do not overlap.
*/
static void
AssertCheckExpandedRanges(BrinDesc *bdesc, Oid colloid, AttrNumber attno,
Form_pg_attribute attr, ExpandedRange *ranges,
int nranges)
{
#ifdef USE_ASSERT_CHECKING
int i;
FmgrInfo *eq;
FmgrInfo *lt;
eq = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid,
BTEqualStrategyNumber);
lt = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid,
BTLessStrategyNumber);
/*
* Each range independently should be valid, i.e. that for the boundary
* values (lower <= upper).
*/
for (i = 0; i < nranges; i++)
{
Datum r;
Datum minval = ranges[i].minval;
Datum maxval = ranges[i].maxval;
if (ranges[i].collapsed) /* collapsed: minval == maxval */
r = FunctionCall2Coll(eq, colloid, minval, maxval);
else /* non-collapsed: minval < maxval */
r = FunctionCall2Coll(lt, colloid, minval, maxval);
Assert(DatumGetBool(r));
}
/*
* And the ranges should be ordered and must not overlap, i.e. upper <
* lower for boundaries of consecutive ranges.
*/
for (i = 0; i < nranges - 1; i++)
{
Datum r;
Datum maxval = ranges[i].maxval;
Datum minval = ranges[i + 1].minval;
r = FunctionCall2Coll(lt, colloid, maxval, minval);
Assert(DatumGetBool(r));
}
#endif
}
/*
* minmax_multi_init
* Initialize the deserialized range list, allocate all the memory.
*
* This is only in-memory representation of the ranges, so we allocate
* enough space for the maximum number of values (so as not to have to do
* repallocs as the ranges grow).
*/
static Ranges *
minmax_multi_init(int maxvalues)
{
Size len;
Ranges *ranges;
Assert(maxvalues > 0);
len = offsetof(Ranges, values); /* fixed header */
len += maxvalues * sizeof(Datum); /* Datum values */
ranges = (Ranges *) palloc0(len);
ranges->maxvalues = maxvalues;
return ranges;
}
/*
* range_deduplicate_values
* Deduplicate the part with values in the simple points.
*
* This is meant to be a cheaper way of reducing the size of the ranges. It
* does not touch the ranges, and only sorts the other values - it does not
* call the distance functions, which may be quite expensive, etc.
*
* We do know the values are not duplicate with the ranges, because we check
* that before adding a new value. Same for the sorted part of values.
*/
static void
range_deduplicate_values(Ranges *range)
{
int i,
n;
int start;
compare_context cxt;
/*
* If there are no unsorted values, we're done (this probably can't
* happen, as we're adding values to unsorted part).
*/
if (range->nsorted == range->nvalues)
return;
/* sort the values */
cxt.colloid = range->colloid;
cxt.cmpFn = range->cmp;
/* the values start right after the ranges (which are always sorted) */
start = 2 * range->nranges;
/*
* XXX This might do a merge sort, to leverage that the first part of the
* array is already sorted. If the sorted part is large, it might be quite
* a bit faster.
*/
qsort_arg(&range->values[start],
range->nvalues, sizeof(Datum),
compare_values, (void *) &cxt);
n = 1;
for (i = 1; i < range->nvalues; i++)
{
/* same as preceding value, so store it */
if (compare_values(&range->values[start + i - 1],
&range->values[start + i],
(void *) &cxt) == 0)
continue;
range->values[start + n] = range->values[start + i];
n++;
}
/* now all the values are sorted */
range->nvalues = n;
range->nsorted = n;
AssertCheckRanges(range, range->cmp, range->colloid);
}
/*
* brin_range_serialize
* Serialize the in-memory representation into a compact varlena value.
*
* Simply copy the header and then also the individual values, as stored
* in the in-memory value array.
*/
static SerializedRanges *
brin_range_serialize(Ranges *range)
{
Size len;
int nvalues;
SerializedRanges *serialized;
Oid typid;
int typlen;
bool typbyval;
char *ptr;
/* simple sanity checks */
Assert(range->nranges >= 0);
Assert(range->nsorted >= 0);
Assert(range->nvalues >= 0);
Assert(range->maxvalues > 0);
Assert(range->target_maxvalues > 0);
/* at this point the range should be compacted to the target size */
Assert(2 * range->nranges + range->nvalues <= range->target_maxvalues);
Assert(range->target_maxvalues <= range->maxvalues);
/* range boundaries are always sorted */
Assert(range->nvalues >= range->nsorted);
/* deduplicate values, if there's unsorted part */
range_deduplicate_values(range);
/* see how many Datum values we actually have */
nvalues = 2 * range->nranges + range->nvalues;
typid = range->typid;
typbyval = get_typbyval(typid);
typlen = get_typlen(typid);
/* header is always needed */
len = offsetof(SerializedRanges, data);
/*
* The space needed depends on data type - for fixed-length data types
* (by-value and some by-reference) it's pretty simple, just multiply
* (attlen * nvalues) and we're done. For variable-length by-reference
* types we need to actually walk all the values and sum the lengths.
*/
if (typlen == -1) /* varlena */
{
int i;
for (i = 0; i < nvalues; i++)
{
len += VARSIZE_ANY(range->values[i]);
}
}
else if (typlen == -2) /* cstring */
{
int i;
for (i = 0; i < nvalues; i++)
{
/* don't forget to include the null terminator ;-) */
len += strlen(DatumGetCString(range->values[i])) + 1;
}
}
else /* fixed-length types (even by-reference) */
{
Assert(typlen > 0);
len += nvalues * typlen;
}
/*
* Allocate the serialized object, copy the basic information. The
* serialized object is a varlena, so update the header.
*/
serialized = (SerializedRanges *) palloc0(len);
SET_VARSIZE(serialized, len);
serialized->typid = typid;
serialized->nranges = range->nranges;
serialized->nvalues = range->nvalues;
serialized->maxvalues = range->target_maxvalues;
/*
* And now copy also the boundary values (like the length calculation this
* depends on the particular data type).
*/
ptr = serialized->data; /* start of the serialized data */
for (int i = 0; i < nvalues; i++)
{
if (typbyval) /* simple by-value data types */
{
Datum tmp;
/*
* For byval types, we need to copy just the significant bytes -
* we can't use memcpy directly, as that assumes little-endian
* behavior. store_att_byval does almost what we need, but it
* requires a properly aligned buffer - the output buffer does not
* guarantee that. So we simply use a local Datum variable (which
* guarantees proper alignment), and then copy the value from it.
*/
store_att_byval(&tmp, range->values[i], typlen);
memcpy(ptr, &tmp, typlen);
ptr += typlen;
}
else if (typlen > 0) /* fixed-length by-ref types */
{
memcpy(ptr, DatumGetPointer(range->values[i]), typlen);
ptr += typlen;
}
else if (typlen == -1) /* varlena */
{
int tmp = VARSIZE_ANY(DatumGetPointer(range->values[i]));
memcpy(ptr, DatumGetPointer(range->values[i]), tmp);
ptr += tmp;
}
else if (typlen == -2) /* cstring */
{
int tmp = strlen(DatumGetCString(range->values[i])) + 1;
memcpy(ptr, DatumGetCString(range->values[i]), tmp);
ptr += tmp;
}
/* make sure we haven't overflown the buffer end */
Assert(ptr <= ((char *) serialized + len));
}
/* exact size */
Assert(ptr == ((char *) serialized + len));
return serialized;
}
/*
* brin_range_deserialize
* Serialize the in-memory representation into a compact varlena value.
*
* Simply copy the header and then also the individual values, as stored
* in the in-memory value array.
*/
static Ranges *
brin_range_deserialize(int maxvalues, SerializedRanges *serialized)
{
int i,
nvalues;
char *ptr,
*dataptr;
bool typbyval;
int typlen;
Size datalen;
Ranges *range;
Assert(serialized->nranges >= 0);
Assert(serialized->nvalues >= 0);
Assert(serialized->maxvalues > 0);
nvalues = 2 * serialized->nranges + serialized->nvalues;
Assert(nvalues <= serialized->maxvalues);
Assert(serialized->maxvalues <= maxvalues);
range = minmax_multi_init(maxvalues);
/* copy the header info */
range->nranges = serialized->nranges;
range->nvalues = serialized->nvalues;
range->nsorted = serialized->nvalues;
range->maxvalues = maxvalues;
range->target_maxvalues = serialized->maxvalues;
range->typid = serialized->typid;
typbyval = get_typbyval(serialized->typid);
typlen = get_typlen(serialized->typid);
/*
* And now deconstruct the values into Datum array. We have to copy the
* data because the serialized representation ignores alignment, and we
* don't want to rely on it being kept around anyway.
*/
ptr = serialized->data;
/*
* We don't want to allocate many pieces, so we just allocate everything
* in one chunk. How much space will we need?
*
* XXX We don't need to copy simple by-value data types.
*/
datalen = 0;
dataptr = NULL;
for (i = 0; (i < nvalues) && (!typbyval); i++)
{
if (typlen > 0) /* fixed-length by-ref types */
datalen += MAXALIGN(typlen);
else if (typlen == -1) /* varlena */
{
datalen += MAXALIGN(VARSIZE_ANY(ptr));
ptr += VARSIZE_ANY(ptr);
}
else if (typlen == -2) /* cstring */
{
Size slen = strlen(ptr) + 1;
datalen += MAXALIGN(slen);
ptr += slen;
}
}
if (datalen > 0)
dataptr = palloc(datalen);
/*
* Restore the source pointer (might have been modified when calculating
* the space we need to allocate).
*/
ptr = serialized->data;
for (i = 0; i < nvalues; i++)
{
if (typbyval) /* simple by-value data types */
{
Datum v = 0;
memcpy(&v, ptr, typlen);
range->values[i] = fetch_att(&v, true, typlen);
ptr += typlen;
}
else if (typlen > 0) /* fixed-length by-ref types */
{
range->values[i] = PointerGetDatum(dataptr);
memcpy(dataptr, ptr, typlen);
dataptr += MAXALIGN(typlen);
ptr += typlen;
}
else if (typlen == -1) /* varlena */
{
range->values[i] = PointerGetDatum(dataptr);
memcpy(dataptr, ptr, VARSIZE_ANY(ptr));
dataptr += MAXALIGN(VARSIZE_ANY(ptr));
ptr += VARSIZE_ANY(ptr);
}
else if (typlen == -2) /* cstring */
{
Size slen = strlen(ptr) + 1;
range->values[i] = PointerGetDatum(dataptr);
memcpy(dataptr, ptr, slen);
dataptr += MAXALIGN(slen);
ptr += slen;
}
/* make sure we haven't overflown the buffer end */
Assert(ptr <= ((char *) serialized + VARSIZE_ANY(serialized)));
}
/* should have consumed the whole input value exactly */
Assert(ptr == ((char *) serialized + VARSIZE_ANY(serialized)));
/* return the deserialized value */
return range;
}
/*
* compare_expanded_ranges
* Compare the expanded ranges - first by minimum, then by maximum.
*
* We do guarantee that ranges in a single Ranges object do not overlap, so it
* may seem strange that we don't order just by minimum. But when merging two
* Ranges (which happens in the union function), the ranges may in fact
* overlap. So we do compare both.
*/
static int
compare_expanded_ranges(const void *a, const void *b, void *arg)
{
ExpandedRange *ra = (ExpandedRange *) a;
ExpandedRange *rb = (ExpandedRange *) b;
Datum r;
compare_context *cxt = (compare_context *) arg;
/* first compare minvals */
r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, ra->minval, rb->minval);
if (DatumGetBool(r))
return -1;
r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, rb->minval, ra->minval);
if (DatumGetBool(r))
return 1;
/* then compare maxvals */
r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, ra->maxval, rb->maxval);
if (DatumGetBool(r))
return -1;
r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, rb->maxval, ra->maxval);
if (DatumGetBool(r))
return 1;
return 0;
}
/*
* compare_values
* Compare the values.
*/
static int
compare_values(const void *a, const void *b, void *arg)
{
Datum *da = (Datum *) a;
Datum *db = (Datum *) b;
Datum r;
compare_context *cxt = (compare_context *) arg;
r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, *da, *db);
if (DatumGetBool(r))
return -1;
r = FunctionCall2Coll(cxt->cmpFn, cxt->colloid, *db, *da);
if (DatumGetBool(r))
return 1;
return 0;
}
/*
* Check if the new value matches one of the existing ranges.
*/
static bool
has_matching_range(BrinDesc *bdesc, Oid colloid, Ranges *ranges,
Datum newval, AttrNumber attno, Oid typid)
{
Datum compar;
Datum minvalue = ranges->values[0];
Datum maxvalue = ranges->values[2 * ranges->nranges - 1];
FmgrInfo *cmpLessFn;
FmgrInfo *cmpGreaterFn;
/* binary search on ranges */
int start,
end;
if (ranges->nranges == 0)
return false;
/*
* Otherwise, need to compare the new value with boundaries of all the
* ranges. First check if it's less than the absolute minimum, which is
* the first value in the array.
*/
cmpLessFn = minmax_multi_get_strategy_procinfo(bdesc, attno, typid,
BTLessStrategyNumber);
compar = FunctionCall2Coll(cmpLessFn, colloid, newval, minvalue);
/* smaller than the smallest value in the range list */
if (DatumGetBool(compar))
return false;
/*
* And now compare it to the existing maximum (last value in the data
* array). But only if we haven't already ruled out a possible match in
* the minvalue check.
*/
cmpGreaterFn = minmax_multi_get_strategy_procinfo(bdesc, attno, typid,
BTGreaterStrategyNumber);
compar = FunctionCall2Coll(cmpGreaterFn, colloid, newval, maxvalue);
if (DatumGetBool(compar))
return false;
/*
* So we know it's in the general min/max, the question is whether it
* falls in one of the ranges or gaps. We'll do a binary search on
* individual ranges - for each range we check equality (value falls into
* the range), and then check ranges either above or below the current
* range.
*/
start = 0; /* first range */
end = (ranges->nranges - 1); /* last range */
while (true)
{
int midpoint = (start + end) / 2;
/* this means we ran out of ranges in the last step */
if (start > end)
return false;
/* copy the min/max values from the ranges */
minvalue = ranges->values[2 * midpoint];
maxvalue = ranges->values[2 * midpoint + 1];
/*
* Is the value smaller than the minval? If yes, we'll recurse to the
* left side of range array.
*/
compar = FunctionCall2Coll(cmpLessFn, colloid, newval, minvalue);
/* smaller than the smallest value in this range */
if (DatumGetBool(compar))
{
end = (midpoint - 1);
continue;
}
/*
* Is the value greater than the minval? If yes, we'll recurse to the
* right side of range array.
*/
compar = FunctionCall2Coll(cmpGreaterFn, colloid, newval, maxvalue);
/* larger than the largest value in this range */
if (DatumGetBool(compar))
{
start = (midpoint + 1);
continue;
}
/* hey, we found a matching range */
return true;
}
return false;
}
/*
* range_contains_value
* See if the new value is already contained in the range list.
*
* We first inspect the list of intervals. We use a small trick - we check
* the value against min/max of the whole range (min of the first interval,
* max of the last one) first, and only inspect the individual intervals if
* this passes.
*
* If the value matches none of the intervals, we check the exact values.
* We simply loop through them and invoke equality operator on them.
*
* The last parameter (full) determines whether we need to search all the
* values, including the unsorted part. With full=false, the unsorted part
* is not searched, which may produce false negatives and duplicate values
* (in the unsorted part only), but when we're building the range that's
* fine - we'll deduplicate before serialization, and it can only happen
* if there already are unsorted values (so it was already modified).
*
* Serialized ranges don't have any unsorted values, so this can't cause
* false negatives during querying.
*/
static bool
range_contains_value(BrinDesc *bdesc, Oid colloid,
AttrNumber attno, Form_pg_attribute attr,
Ranges *ranges, Datum newval, bool full)
{
int i;
FmgrInfo *cmpEqualFn;
Oid typid = attr->atttypid;
/*
* First inspect the ranges, if there are any. We first check the whole
* range, and only when there's still a chance of getting a match we
* inspect the individual ranges.
*/
if (has_matching_range(bdesc, colloid, ranges, newval, attno, typid))
return true;
cmpEqualFn = minmax_multi_get_strategy_procinfo(bdesc, attno, typid,
BTEqualStrategyNumber);
/*
* There is no matching range, so let's inspect the sorted values.
*
* We do a sequential search for small numbers of values, and binary
* search once we have more than 16 values. This threshold is somewhat
* arbitrary, as it depends on how expensive the comparison function is.
*
* XXX If we use the threshold here, maybe we should do the same thing in
* has_matching_range? Or maybe we should do the bin search all the time?
*
* XXX We could use the same optimization as for ranges, to check if the
* value is between min/max, to maybe rule out all sorted values without
* having to inspect all of them.
*/
if (ranges->nsorted >= 16)
{
compare_context cxt;
cxt.colloid = ranges->colloid;
cxt.cmpFn = ranges->cmp;
if (bsearch_arg(&newval, &ranges->values[2 * ranges->nranges],
ranges->nsorted, sizeof(Datum),
compare_values, (void *) &cxt) != NULL)
return true;
}
else
{
for (i = 2 * ranges->nranges; i < 2 * ranges->nranges + ranges->nsorted; i++)
{
Datum compar;
compar = FunctionCall2Coll(cmpEqualFn, colloid, newval, ranges->values[i]);
/* found an exact match */
if (DatumGetBool(compar))
return true;
}
}
/* If not asked to inspect the unsorted part, we're done. */
if (!full)
return false;
/* Inspect the unsorted part. */
for (i = 2 * ranges->nranges + ranges->nsorted; i < 2 * ranges->nranges + ranges->nvalues; i++)
{
Datum compar;
compar = FunctionCall2Coll(cmpEqualFn, colloid, newval, ranges->values[i]);
/* found an exact match */
if (DatumGetBool(compar))
return true;
}
/* the value is not covered by this BRIN tuple */
return false;
}
/*
* Expand ranges from Ranges into ExpandedRange array. This expects the
* eranges to be pre-allocated and with the correct size - there needs to be
* (nranges + nvalues) elements.
*
* The order of expanded ranges is arbitrary. We do expand the ranges first,
* and this part is sorted. But then we expand the values, and this part may
* be unsorted.
*/
static void
fill_expanded_ranges(ExpandedRange *eranges, int neranges, Ranges *ranges)
{
int idx;
int i;
/* Check that the output array has the right size. */
Assert(neranges == (ranges->nranges + ranges->nvalues));
idx = 0;
for (i = 0; i < ranges->nranges; i++)
{
eranges[idx].minval = ranges->values[2 * i];
eranges[idx].maxval = ranges->values[2 * i + 1];
eranges[idx].collapsed = false;
idx++;
Assert(idx <= neranges);
}
for (i = 0; i < ranges->nvalues; i++)
{
eranges[idx].minval = ranges->values[2 * ranges->nranges + i];
eranges[idx].maxval = ranges->values[2 * ranges->nranges + i];
eranges[idx].collapsed = true;
idx++;
Assert(idx <= neranges);
}
/* Did we produce the expected number of elements? */
Assert(idx == neranges);
return;
}
/*
* Sort and deduplicate expanded ranges.
*
* The ranges may be deduplicated - we're simply appending values, without
* checking for duplicates etc. So maybe the deduplication will reduce the
* number of ranges enough, and we won't have to compute the distances etc.
*
* Returns the number of expanded ranges.
*/
static int
sort_expanded_ranges(FmgrInfo *cmp, Oid colloid,
ExpandedRange *eranges, int neranges)
{
int n;
int i;
compare_context cxt;
Assert(neranges > 0);
/* sort the values */
cxt.colloid = colloid;
cxt.cmpFn = cmp;
/*
* XXX We do qsort on all the values, but we could also leverage the fact
* that some of the input data is already sorted (all the ranges and maybe
* some of the points) and do merge sort.
*/
qsort_arg(eranges, neranges, sizeof(ExpandedRange),
compare_expanded_ranges, (void *) &cxt);
/*
* Deduplicate the ranges - simply compare each range to the preceding
* one, and skip the duplicate ones.
*/
n = 1;
for (i = 1; i < neranges; i++)
{
/* if the current range is equal to the preceding one, do nothing */
if (!compare_expanded_ranges(&eranges[i - 1], &eranges[i], (void *) &cxt))
continue;
/* otherwise, copy it to n-th place (if not already there) */
if (i != n)
memcpy(&eranges[n], &eranges[i], sizeof(ExpandedRange));
n++;
}
Assert((n > 0) && (n <= neranges));
return n;
}
/*
* When combining multiple Range values (in union function), some of the
* ranges may overlap. We simply merge the overlapping ranges to fix that.
*
* XXX This assumes the expanded ranges were previously sorted (by minval
* and then maxval). We leverage this when detecting overlap.
*/
static int
merge_overlapping_ranges(FmgrInfo *cmp, Oid colloid,
ExpandedRange *eranges, int neranges)
{
int idx;
/* Merge ranges (idx) and (idx+1) if they overlap. */
idx = 0;
while (idx < (neranges - 1))
{
Datum r;
/*
* comparing [?,maxval] vs. [minval,?] - the ranges overlap if (minval
* < maxval)
*/
r = FunctionCall2Coll(cmp, colloid,
eranges[idx].maxval,
eranges[idx + 1].minval);
/*
* Nope, maxval < minval, so no overlap. And we know the ranges are
* ordered, so there are no more overlaps, because all the remaining
* ranges have greater or equal minval.
*/
if (DatumGetBool(r))
{
/* proceed to the next range */
idx += 1;
continue;
}
/*
* So ranges 'idx' and 'idx+1' do overlap, but we don't know if
* 'idx+1' is contained in 'idx', or if they overlap only partially.
* So compare the upper bounds and keep the larger one.
*/
r = FunctionCall2Coll(cmp, colloid,
eranges[idx].maxval,
eranges[idx + 1].maxval);
if (DatumGetBool(r))
eranges[idx].maxval = eranges[idx + 1].maxval;
/*
* The range certainly is no longer collapsed (irrespectively of the
* previous state).
*/
eranges[idx].collapsed = false;
/*
* Now get rid of the (idx+1) range entirely by shifting the remaining
* ranges by 1. There are neranges elements, and we need to move
* elements from (idx+2). That means the number of elements to move is
* [ncranges - (idx+2)].
*/
memmove(&eranges[idx + 1], &eranges[idx + 2],
(neranges - (idx + 2)) * sizeof(ExpandedRange));
/*
* Decrease the number of ranges, and repeat (with the same range, as
* it might overlap with additional ranges thanks to the merge).
*/
neranges--;
}
return neranges;
}
/*
* Simple comparator for distance values, comparing the double value.
* This is intentionally sorting the distances in descending order, i.e.
* the longer gaps will be at the front.
*/
static int
compare_distances(const void *a, const void *b)
{
DistanceValue *da = (DistanceValue *) a;
DistanceValue *db = (DistanceValue *) b;
if (da->value < db->value)
return 1;
else if (da->value > db->value)
return -1;
return 0;
}
/*
* Given an array of expanded ranges, compute size of the gaps between each
* range. For neranges there are (neranges-1) gaps.
*
* We simply call the "distance" function to compute the (max-min) for pairs
* of consecutive ranges. The function may be fairly expensive, so we do that
* just once (and then use it to pick as many ranges to merge as possible).
*
* See reduce_expanded_ranges for details.
*/
static DistanceValue *
build_distances(FmgrInfo *distanceFn, Oid colloid,
ExpandedRange *eranges, int neranges)
{
int i;
int ndistances;
DistanceValue *distances;
Assert(neranges >= 2);
ndistances = (neranges - 1);
distances = (DistanceValue *) palloc0(sizeof(DistanceValue) * ndistances);
/*
* Walk through the ranges once and compute the distance between the
* ranges so that we can sort them once.
*/
for (i = 0; i < ndistances; i++)
{
Datum a1,
a2,
r;
a1 = eranges[i].maxval;
a2 = eranges[i + 1].minval;
/* compute length of the gap (between max/min) */
r = FunctionCall2Coll(distanceFn, colloid, a1, a2);
/* remember the index of the gap the distance is for */
distances[i].index = i;
distances[i].value = DatumGetFloat8(r);
}
/*
* Sort the distances in descending order, so that the longest gaps are at
* the front.
*/
pg_qsort(distances, ndistances, sizeof(DistanceValue), compare_distances);
return distances;
}
/*
* Builds expanded ranges for the existing ranges (and single-point ranges),
* and also the new value (which did not fit into the array). This expanded
* representation makes the processing a bit easier, as it allows handling
* ranges and points the same way.
*
* We sort and deduplicate the expanded ranges - this is necessary, because
* the points may be unsorted. And moreover the two parts (ranges and
* points) are sorted on their own.
*/
static ExpandedRange *
build_expanded_ranges(FmgrInfo *cmp, Oid colloid, Ranges *ranges,
int *nranges)
{
int neranges;
ExpandedRange *eranges;
/* both ranges and points are expanded into a separate element */
neranges = ranges->nranges + ranges->nvalues;
eranges = (ExpandedRange *) palloc0(neranges * sizeof(ExpandedRange));
/* fill the expanded ranges */
fill_expanded_ranges(eranges, neranges, ranges);
/* sort and deduplicate the expanded ranges */
neranges = sort_expanded_ranges(cmp, colloid, eranges, neranges);
/* remember how many ranges we built */
*nranges = neranges;
return eranges;
}
#ifdef USE_ASSERT_CHECKING
/*
* Counts boundary values needed to store the ranges. Each single-point
* range is stored using a single value, each regular range needs two.
*/
static int
count_values(ExpandedRange *cranges, int ncranges)
{
int i;
int count;
count = 0;
for (i = 0; i < ncranges; i++)
{
if (cranges[i].collapsed)
count += 1;
else
count += 2;
}
return count;
}
#endif
/*
* reduce_expanded_ranges
* reduce the ranges until the number of values is low enough
*
* Combines ranges until the number of boundary values drops below the
* threshold specified by max_values. This happens by merging enough
* ranges by the distance between them.
*
* Returns the number of result ranges.
*
* We simply use the global min/max and then add boundaries for enough
* largest gaps. Each gap adds 2 values, so we simply use (target/2-1)
* distances. Then we simply sort all the values - each two values are
* a boundary of a range (possibly collapsed).
*
* XXX Some of the ranges may be collapsed (i.e. the min/max values are
* equal), but we ignore that for now. We could repeat the process,
* adding a couple more gaps recursively.
*
* XXX The ranges to merge are selected solely using the distance. But
* that may not be the best strategy, for example when multiple gaps
* are of equal (or very similar) length.
*
* Consider for example points 1, 2, 3, .., 64, which have gaps of the
* same length 1 of course. In that case, we tend to pick the first
* gap of that length, which leads to this:
*
* step 1: [1, 2], 3, 4, 5, .., 64
* step 2: [1, 3], 4, 5, .., 64
* step 3: [1, 4], 5, .., 64
* ...
*
* So in the end we'll have one "large" range and multiple small points.
* That may be fine, but it seems a bit strange and non-optimal. Maybe
* we should consider other things when picking ranges to merge - e.g.
* length of the ranges? Or perhaps randomize the choice of ranges, with
* probability inversely proportional to the distance (the gap lengths
* may be very close, but not exactly the same).
*
* XXX Or maybe we could just handle this by using random value as a
* tie-break, or by adding random noise to the actual distance.
*/
static int
reduce_expanded_ranges(ExpandedRange *eranges, int neranges,
DistanceValue *distances, int max_values,
FmgrInfo *cmp, Oid colloid)
{
int i;
int nvalues;
Datum *values;
compare_context cxt;
/* total number of gaps between ranges */
int ndistances = (neranges - 1);
/* number of gaps to keep */
int keep = (max_values / 2 - 1);
/*
* Maybe we have a sufficiently low number of ranges already?
*
* XXX This should happen before we actually do the expensive stuff like
* sorting, so maybe this should be just an assert.
*/
if (keep >= ndistances)
return neranges;
/* sort the values */
cxt.colloid = colloid;
cxt.cmpFn = cmp;
/* allocate space for the boundary values */
nvalues = 0;
values = (Datum *) palloc(sizeof(Datum) * max_values);
/* add the global min/max values, from the first/last range */
values[nvalues++] = eranges[0].minval;
values[nvalues++] = eranges[neranges - 1].maxval;
/* add boundary values for enough gaps */
for (i = 0; i < keep; i++)
{
/* index of the gap between (index) and (index+1) ranges */
int index = distances[i].index;
Assert((index >= 0) && ((index + 1) < neranges));
/* add max from the preceding range, minval from the next one */
values[nvalues++] = eranges[index].maxval;
values[nvalues++] = eranges[index + 1].minval;
Assert(nvalues <= max_values);
}
/* We should have an even number of range values. */
Assert(nvalues % 2 == 0);
/*
* Sort the values using the comparator function, and form ranges from the
* sorted result.
*/
qsort_arg(values, nvalues, sizeof(Datum),
compare_values, (void *) &cxt);
/* We have nvalues boundary values, which means nvalues/2 ranges. */
for (i = 0; i < (nvalues / 2); i++)
{
eranges[i].minval = values[2 * i];
eranges[i].maxval = values[2 * i + 1];
/* if the boundary values are the same, it's a collapsed range */
eranges[i].collapsed = (compare_values(&values[2 * i],
&values[2 * i + 1],
&cxt) == 0);
}
return (nvalues / 2);
}
/*
* Store the boundary values from ExpandedRanges back into 'ranges' (using
* only the minimal number of values needed).
*/
static void
store_expanded_ranges(Ranges *ranges, ExpandedRange *eranges, int neranges)
{
int i;
int idx = 0;
/* first copy in the regular ranges */
ranges->nranges = 0;
for (i = 0; i < neranges; i++)
{
if (!eranges[i].collapsed)
{
ranges->values[idx++] = eranges[i].minval;
ranges->values[idx++] = eranges[i].maxval;
ranges->nranges++;
}
}
/* now copy in the collapsed ones */
ranges->nvalues = 0;
for (i = 0; i < neranges; i++)
{
if (eranges[i].collapsed)
{
ranges->values[idx++] = eranges[i].minval;
ranges->nvalues++;
}
}
/* all the values are sorted */
ranges->nsorted = ranges->nvalues;
Assert(count_values(eranges, neranges) == 2 * ranges->nranges + ranges->nvalues);
Assert(2 * ranges->nranges + ranges->nvalues <= ranges->maxvalues);
}
/*
* Consider freeing space in the ranges. Checks if there's space for at least
* one new value, and performs compaction if needed.
*
* Returns true if the value was actually modified.
*/
static bool
ensure_free_space_in_buffer(BrinDesc *bdesc, Oid colloid,
AttrNumber attno, Form_pg_attribute attr,
Ranges *range)
{
MemoryContext ctx;
MemoryContext oldctx;
FmgrInfo *cmpFn,
*distanceFn;
/* expanded ranges */
ExpandedRange *eranges;
int neranges;
DistanceValue *distances;
/*
* If there is free space in the buffer, we're done without having to
* modify anything.
*/
if (2 * range->nranges + range->nvalues < range->maxvalues)
return false;
/* we'll certainly need the comparator, so just look it up now */
cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid,
BTLessStrategyNumber);
/* deduplicate values, if there's an unsorted part */
range_deduplicate_values(range);
/*
* Did we reduce enough free space by just the deduplication?
*
* We don't simply check against range->maxvalues again. The deduplication
* might have freed very little space (e.g. just one value), forcing us to
* do deduplication very often. In that case, it's better to do the
* compaction and reduce more space.
*/
if (2 * range->nranges + range->nvalues <= range->maxvalues * MINMAX_BUFFER_LOAD_FACTOR)
return true;
/*
* We need to combine some of the existing ranges, to reduce the number of
* values we have to store.
*
* The distanceFn calls (which may internally call e.g. numeric_le) may
* allocate quite a bit of memory, and we must not leak it (we might have
* to do this repeatedly, even for a single BRIN page range). Otherwise
* we'd have problems e.g. when building new indexes. So we use a memory
* context and make sure we free the memory at the end (so if we call the
* distance function many times, it might be an issue, but meh).
*/
ctx = AllocSetContextCreate(CurrentMemoryContext,
"minmax-multi context",
ALLOCSET_DEFAULT_SIZES);
oldctx = MemoryContextSwitchTo(ctx);
/* build the expanded ranges */
eranges = build_expanded_ranges(cmpFn, colloid, range, &neranges);
/* and we'll also need the 'distance' procedure */
distanceFn = minmax_multi_get_procinfo(bdesc, attno, PROCNUM_DISTANCE);
/* build array of gap distances and sort them in ascending order */
distances = build_distances(distanceFn, colloid, eranges, neranges);
/*
* Combine ranges until we release at least 50% of the space. This
* threshold is somewhat arbitrary, perhaps needs tuning. We must not use
* too low or high value.
*/
neranges = reduce_expanded_ranges(eranges, neranges, distances,
range->maxvalues * MINMAX_BUFFER_LOAD_FACTOR,
cmpFn, colloid);
/* Make sure we've sufficiently reduced the number of ranges. */
Assert(count_values(eranges, neranges) <= range->maxvalues * MINMAX_BUFFER_LOAD_FACTOR);
/* decompose the expanded ranges into regular ranges and single values */
store_expanded_ranges(range, eranges, neranges);
MemoryContextSwitchTo(oldctx);
MemoryContextDelete(ctx);
/* Did we break the ranges somehow? */
AssertCheckRanges(range, cmpFn, colloid);
return true;
}
/*
* range_add_value
* Add the new value to the minmax-multi range.
*/
static bool
range_add_value(BrinDesc *bdesc, Oid colloid,
AttrNumber attno, Form_pg_attribute attr,
Ranges *ranges, Datum newval)
{
FmgrInfo *cmpFn;
bool modified = false;
/* we'll certainly need the comparator, so just look it up now */
cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid,
BTLessStrategyNumber);
/* comprehensive checks of the input ranges */
AssertCheckRanges(ranges, cmpFn, colloid);
/*
* Make sure there's enough free space in the buffer. We only trigger this
* when the buffer is full, which means it had to be modified as we size
* it to be larger than what is stored on disk.
*
* This needs to happen before we check if the value is contained in the
* range, because the value might be in the unsorted part, and we don't
* check that in range_contains_value. The deduplication would then move
* it to the sorted part, and we'd add the value too, which violates the
* rule that we never have duplicates with the ranges or sorted values.
*
* We might also deduplicate and recheck if the value is contained, but
* that seems like overkill. We'd need to deduplicate anyway, so why not
* do it now.
*/
modified = ensure_free_space_in_buffer(bdesc, colloid,
attno, attr, ranges);
/*
* Bail out if the value already is covered by the range.
*
* We could also add values until we hit values_per_range, and then do the
* deduplication in a batch, hoping for better efficiency. But that would
* mean we actually modify the range every time, which means having to
* serialize the value, which does palloc, walks the values, copies them,
* etc. Not exactly cheap.
*
* So instead we do the check, which should be fairly cheap - assuming the
* comparator function is not very expensive.
*
* This also implies the values array can't contain duplicate values.
*/
if (range_contains_value(bdesc, colloid, attno, attr, ranges, newval, false))
return modified;
/* Make a copy of the value, if needed. */
newval = datumCopy(newval, attr->attbyval, attr->attlen);
/*
* If there's space in the values array, copy it in and we're done.
*
* We do want to keep the values sorted (to speed up searches), so we do a
* simple insertion sort. We could do something more elaborate, e.g. by
* sorting the values only now and then, but for small counts (e.g. when
* maxvalues is 64) this should be fine.
*/
ranges->values[2 * ranges->nranges + ranges->nvalues] = newval;
ranges->nvalues++;
/* If we added the first value, we can consider it as sorted. */
if (ranges->nvalues == 1)
ranges->nsorted = 1;
/*
* Check we haven't broken the ordering of boundary values (checks both
* parts, but that doesn't hurt).
*/
AssertCheckRanges(ranges, cmpFn, colloid);
/* Check the range contains the value we just added. */
Assert(range_contains_value(bdesc, colloid, attno, attr, ranges, newval, true));
/* yep, we've modified the range */
return true;
}
/*
* Generate range representation of data collected during "batch mode".
* This is similar to reduce_expanded_ranges, except that we can't assume
* the values are sorted and there may be duplicate values.
*/
static void
compactify_ranges(BrinDesc *bdesc, Ranges *ranges, int max_values)
{
FmgrInfo *cmpFn,
*distanceFn;
/* expanded ranges */
ExpandedRange *eranges;
int neranges;
DistanceValue *distances;
MemoryContext ctx;
MemoryContext oldctx;
/*
* Do we need to actually compactify anything?
*
* There are two reasons why compaction may be needed - firstly, there may
* be too many values, or some of the values may be unsorted.
*/
if ((ranges->nranges * 2 + ranges->nvalues <= max_values) &&
(ranges->nsorted == ranges->nvalues))
return;
/* we'll certainly need the comparator, so just look it up now */
cmpFn = minmax_multi_get_strategy_procinfo(bdesc, ranges->attno, ranges->typid,
BTLessStrategyNumber);
/* and we'll also need the 'distance' procedure */
distanceFn = minmax_multi_get_procinfo(bdesc, ranges->attno, PROCNUM_DISTANCE);
/*
* The distanceFn calls (which may internally call e.g. numeric_le) may
* allocate quite a bit of memory, and we must not leak it. Otherwise,
* we'd have problems e.g. when building indexes. So we create a local
* memory context and make sure we free the memory before leaving this
* function (not after every call).
*/
ctx = AllocSetContextCreate(CurrentMemoryContext,
"minmax-multi context",
ALLOCSET_DEFAULT_SIZES);
oldctx = MemoryContextSwitchTo(ctx);
/* build the expanded ranges */
eranges = build_expanded_ranges(cmpFn, ranges->colloid, ranges, &neranges);
/* build array of gap distances and sort them in ascending order */
distances = build_distances(distanceFn, ranges->colloid,
eranges, neranges);
/*
* Combine ranges until we get below max_values. We don't use any scale
* factor, because this is used during serialization, and we don't expect
* more tuples to be inserted anytime soon.
*/
neranges = reduce_expanded_ranges(eranges, neranges, distances,
max_values, cmpFn, ranges->colloid);
Assert(count_values(eranges, neranges) <= max_values);
/* transform back into regular ranges and single values */
store_expanded_ranges(ranges, eranges, neranges);
/* check all the range invariants */
AssertCheckRanges(ranges, cmpFn, ranges->colloid);
MemoryContextSwitchTo(oldctx);
MemoryContextDelete(ctx);
}
Datum
brin_minmax_multi_opcinfo(PG_FUNCTION_ARGS)
{
BrinOpcInfo *result;
/*
* opaque->strategy_procinfos is initialized lazily; here it is set to
* all-uninitialized by palloc0 which sets fn_oid to InvalidOid.
*/
result = palloc0(MAXALIGN(SizeofBrinOpcInfo(1)) +
sizeof(MinmaxMultiOpaque));
result->oi_nstored = 1;
result->oi_regular_nulls = true;
result->oi_opaque = (MinmaxMultiOpaque *)
MAXALIGN((char *) result + SizeofBrinOpcInfo(1));
result->oi_typcache[0] = lookup_type_cache(PG_BRIN_MINMAX_MULTI_SUMMARYOID, 0);
PG_RETURN_POINTER(result);
}
/*
* Compute the distance between two float4 values (plain subtraction).
*/
Datum
brin_minmax_multi_distance_float4(PG_FUNCTION_ARGS)
{
float a1 = PG_GETARG_FLOAT4(0);
float a2 = PG_GETARG_FLOAT4(1);
/* if both values are NaN, then we consider them the same */
if (isnan(a1) && isnan(a2))
PG_RETURN_FLOAT8(0.0);
/* if one value is NaN, use infinite distance */
if (isnan(a1) || isnan(a2))
PG_RETURN_FLOAT8(get_float8_infinity());
/*
* We know the values are range boundaries, but the range may be collapsed
* (i.e. single points), with equal values.
*/
Assert(a1 <= a2);
PG_RETURN_FLOAT8((double) a2 - (double) a1);
}
/*
* Compute the distance between two float8 values (plain subtraction).
*/
Datum
brin_minmax_multi_distance_float8(PG_FUNCTION_ARGS)
{
double a1 = PG_GETARG_FLOAT8(0);
double a2 = PG_GETARG_FLOAT8(1);
/* if both values are NaN, then we consider them the same */
if (isnan(a1) && isnan(a2))
PG_RETURN_FLOAT8(0.0);
/* if one value is NaN, use infinite distance */
if (isnan(a1) || isnan(a2))
PG_RETURN_FLOAT8(get_float8_infinity());
/*
* We know the values are range boundaries, but the range may be collapsed
* (i.e. single points), with equal values.
*/
Assert(a1 <= a2);
PG_RETURN_FLOAT8(a2 - a1);
}
/*
* Compute the distance between two int2 values (plain subtraction).
*/
Datum
brin_minmax_multi_distance_int2(PG_FUNCTION_ARGS)
{
int16 a1 = PG_GETARG_INT16(0);
int16 a2 = PG_GETARG_INT16(1);
/*
* We know the values are range boundaries, but the range may be collapsed
* (i.e. single points), with equal values.
*/
Assert(a1 <= a2);
PG_RETURN_FLOAT8((double) a2 - (double) a1);
}
/*
* Compute the distance between two int4 values (plain subtraction).
*/
Datum
brin_minmax_multi_distance_int4(PG_FUNCTION_ARGS)
{
int32 a1 = PG_GETARG_INT32(0);
int32 a2 = PG_GETARG_INT32(1);
/*
* We know the values are range boundaries, but the range may be collapsed
* (i.e. single points), with equal values.
*/
Assert(a1 <= a2);
PG_RETURN_FLOAT8((double) a2 - (double) a1);
}
/*
* Compute the distance between two int8 values (plain subtraction).
*/
Datum
brin_minmax_multi_distance_int8(PG_FUNCTION_ARGS)
{
int64 a1 = PG_GETARG_INT64(0);
int64 a2 = PG_GETARG_INT64(1);
/*
* We know the values are range boundaries, but the range may be collapsed
* (i.e. single points), with equal values.
*/
Assert(a1 <= a2);
PG_RETURN_FLOAT8((double) a2 - (double) a1);
}
/*
* Compute the distance between two tid values (by mapping them to float8 and
* then subtracting them).
*/
Datum
brin_minmax_multi_distance_tid(PG_FUNCTION_ARGS)
{
double da1,
da2;
ItemPointer pa1 = (ItemPointer) PG_GETARG_DATUM(0);
ItemPointer pa2 = (ItemPointer) PG_GETARG_DATUM(1);
/*
* We know the values are range boundaries, but the range may be collapsed
* (i.e. single points), with equal values.
*/
Assert(ItemPointerCompare(pa1, pa2) <= 0);
/*
* We use the no-check variants here, because user-supplied values may
* have (ip_posid == 0). See ItemPointerCompare.
*/
da1 = ItemPointerGetBlockNumberNoCheck(pa1) * MaxHeapTuplesPerPage +
ItemPointerGetOffsetNumberNoCheck(pa1);
da2 = ItemPointerGetBlockNumberNoCheck(pa2) * MaxHeapTuplesPerPage +
ItemPointerGetOffsetNumberNoCheck(pa2);
PG_RETURN_FLOAT8(da2 - da1);
}
/*
* Compute the distance between two numeric values (plain subtraction).
*/
Datum
brin_minmax_multi_distance_numeric(PG_FUNCTION_ARGS)
{
Datum d;
Datum a1 = PG_GETARG_DATUM(0);
Datum a2 = PG_GETARG_DATUM(1);
/*
* We know the values are range boundaries, but the range may be collapsed
* (i.e. single points), with equal values.
*/
Assert(DatumGetBool(DirectFunctionCall2(numeric_le, a1, a2)));
d = DirectFunctionCall2(numeric_sub, a2, a1); /* a2 - a1 */
PG_RETURN_FLOAT8(DirectFunctionCall1(numeric_float8, d));
}
/*
* Compute the approximate distance between two UUID values.
*
* XXX We do not need a perfectly accurate value, so we approximate the
* deltas (which would have to be 128-bit integers) with a 64-bit float.
* The small inaccuracies do not matter in practice, in the worst case
* we'll decide to merge ranges that are not the closest ones.
*/
Datum
brin_minmax_multi_distance_uuid(PG_FUNCTION_ARGS)
{
int i;
float8 delta = 0;
Datum a1 = PG_GETARG_DATUM(0);
Datum a2 = PG_GETARG_DATUM(1);
pg_uuid_t *u1 = DatumGetUUIDP(a1);
pg_uuid_t *u2 = DatumGetUUIDP(a2);
/*
* We know the values are range boundaries, but the range may be collapsed
* (i.e. single points), with equal values.
*/
Assert(DatumGetBool(DirectFunctionCall2(uuid_le, a1, a2)));
/* compute approximate delta as a double precision value */
for (i = UUID_LEN - 1; i >= 0; i--)
{
delta += (int) u2->data[i] - (int) u1->data[i];
delta /= 256;
}
Assert(delta >= 0);
PG_RETURN_FLOAT8(delta);
}
/*
* Compute the approximate distance between two dates.
*/
Datum
brin_minmax_multi_distance_date(PG_FUNCTION_ARGS)
{
DateADT dateVal1 = PG_GETARG_DATEADT(0);
DateADT dateVal2 = PG_GETARG_DATEADT(1);
if (DATE_NOT_FINITE(dateVal1) || DATE_NOT_FINITE(dateVal2))
PG_RETURN_FLOAT8(0);
PG_RETURN_FLOAT8(dateVal1 - dateVal2);
}
/*
* Compute the approximate distance between two time (without tz) values.
*
* TimeADT is just an int64, so we simply subtract the values directly.
*/
Datum
brin_minmax_multi_distance_time(PG_FUNCTION_ARGS)
{
float8 delta = 0;
TimeADT ta = PG_GETARG_TIMEADT(0);
TimeADT tb = PG_GETARG_TIMEADT(1);
delta = (tb - ta);
Assert(delta >= 0);
PG_RETURN_FLOAT8(delta);
}
/*
* Compute the approximate distance between two timetz values.
*
* Simply subtracts the TimeADT (int64) values embedded in TimeTzADT.
*/
Datum
brin_minmax_multi_distance_timetz(PG_FUNCTION_ARGS)
{
float8 delta = 0;
TimeTzADT *ta = PG_GETARG_TIMETZADT_P(0);
TimeTzADT *tb = PG_GETARG_TIMETZADT_P(1);
delta = (tb->time - ta->time) + (tb->zone - ta->zone) * USECS_PER_SEC;
Assert(delta >= 0);
PG_RETURN_FLOAT8(delta);
}
/*
* Compute the distance between two timestamp values.
*/
Datum
brin_minmax_multi_distance_timestamp(PG_FUNCTION_ARGS)
{
float8 delta = 0;
Timestamp dt1 = PG_GETARG_TIMESTAMP(0);
Timestamp dt2 = PG_GETARG_TIMESTAMP(1);
if (TIMESTAMP_NOT_FINITE(dt1) || TIMESTAMP_NOT_FINITE(dt2))
PG_RETURN_FLOAT8(0);
delta = dt2 - dt1;
Assert(delta >= 0);
PG_RETURN_FLOAT8(delta);
}
/*
* Compute the distance between two interval values.
*/
Datum
brin_minmax_multi_distance_interval(PG_FUNCTION_ARGS)
{
float8 delta = 0;
Interval *ia = PG_GETARG_INTERVAL_P(0);
Interval *ib = PG_GETARG_INTERVAL_P(1);
Interval *result;
int64 dayfraction;
int64 days;
result = (Interval *) palloc(sizeof(Interval));
result->month = ib->month - ia->month;
/* overflow check copied from int4mi */
if (!SAMESIGN(ib->month, ia->month) &&
!SAMESIGN(result->month, ib->month))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("interval out of range")));
result->day = ib->day - ia->day;
if (!SAMESIGN(ib->day, ia->day) &&
!SAMESIGN(result->day, ib->day))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("interval out of range")));
result->time = ib->time - ia->time;
if (!SAMESIGN(ib->time, ia->time) &&
!SAMESIGN(result->time, ib->time))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("interval out of range")));
/*
* Delta is (fractional) number of days between the intervals. Assume
* months have 30 days for consistency with interval_cmp_internal. We
* don't need to be exact, in the worst case we'll build a bit less
* efficient ranges. But we should not contradict interval_cmp.
*/
dayfraction = result->time % USECS_PER_DAY;
days = result->time / USECS_PER_DAY;
days += result->month * INT64CONST(30);
days += result->day;
/* convert to double precision */
delta = (double) days + dayfraction / (double) USECS_PER_DAY;
Assert(delta >= 0);
PG_RETURN_FLOAT8(delta);
}
/*
* Compute the distance between two pg_lsn values.
*
* LSN is just an int64 encoding position in the stream, so just subtract
* those int64 values directly.
*/
Datum
brin_minmax_multi_distance_pg_lsn(PG_FUNCTION_ARGS)
{
float8 delta = 0;
XLogRecPtr lsna = PG_GETARG_LSN(0);
XLogRecPtr lsnb = PG_GETARG_LSN(1);
delta = (lsnb - lsna);
Assert(delta >= 0);
PG_RETURN_FLOAT8(delta);
}
/*
* Compute the distance between two macaddr values.
*
* mac addresses are treated as 6 unsigned chars, so do the same thing we
* already do for UUID values.
*/
Datum
brin_minmax_multi_distance_macaddr(PG_FUNCTION_ARGS)
{
float8 delta;
macaddr *a = PG_GETARG_MACADDR_P(0);
macaddr *b = PG_GETARG_MACADDR_P(1);
delta = ((float8) b->f - (float8) a->f);
delta /= 256;
delta += ((float8) b->e - (float8) a->e);
delta /= 256;
delta += ((float8) b->d - (float8) a->d);
delta /= 256;
delta += ((float8) b->c - (float8) a->c);
delta /= 256;
delta += ((float8) b->b - (float8) a->b);
delta /= 256;
delta += ((float8) b->a - (float8) a->a);
delta /= 256;
Assert(delta >= 0);
PG_RETURN_FLOAT8(delta);
}
/*
* Compute the distance between two macaddr8 values.
*
* macaddr8 addresses are 8 unsigned chars, so do the same thing we
* already do for UUID values.
*/
Datum
brin_minmax_multi_distance_macaddr8(PG_FUNCTION_ARGS)
{
float8 delta;
macaddr8 *a = PG_GETARG_MACADDR8_P(0);
macaddr8 *b = PG_GETARG_MACADDR8_P(1);
delta = ((float8) b->h - (float8) a->h);
delta /= 256;
delta += ((float8) b->g - (float8) a->g);
delta /= 256;
delta += ((float8) b->f - (float8) a->f);
delta /= 256;
delta += ((float8) b->e - (float8) a->e);
delta /= 256;
delta += ((float8) b->d - (float8) a->d);
delta /= 256;
delta += ((float8) b->c - (float8) a->c);
delta /= 256;
delta += ((float8) b->b - (float8) a->b);
delta /= 256;
delta += ((float8) b->a - (float8) a->a);
delta /= 256;
Assert(delta >= 0);
PG_RETURN_FLOAT8(delta);
}
/*
* Compute the distance between two inet values.
*
* The distance is defined as the difference between 32-bit/128-bit values,
* depending on the IP version. The distance is computed by subtracting
* the bytes and normalizing it to [0,1] range for each IP family.
* Addresses from different families are considered to be in maximum
* distance, which is 1.0.
*
* XXX Does this need to consider the mask (bits)? For now, it's ignored.
*/
Datum
brin_minmax_multi_distance_inet(PG_FUNCTION_ARGS)
{
float8 delta;
int i;
int len;
unsigned char *addra,
*addrb;
inet *ipa = PG_GETARG_INET_PP(0);
inet *ipb = PG_GETARG_INET_PP(1);
int lena,
lenb;
/*
* If the addresses are from different families, consider them to be in
* maximal possible distance (which is 1.0).
*/
if (ip_family(ipa) != ip_family(ipb))
PG_RETURN_FLOAT8(1.0);
addra = (unsigned char *) palloc(ip_addrsize(ipa));
memcpy(addra, ip_addr(ipa), ip_addrsize(ipa));
addrb = (unsigned char *) palloc(ip_addrsize(ipb));
memcpy(addrb, ip_addr(ipb), ip_addrsize(ipb));
/*
* The length is calculated from the mask length, because we sort the
* addresses by first address in the range, so A.B.C.D/24 < A.B.C.1 (the
* first range starts at A.B.C.0, which is before A.B.C.1). We don't want
* to produce a negative delta in this case, so we just cut the extra
* bytes.
*
* XXX Maybe this should be a bit more careful and cut the bits, not just
* whole bytes.
*/
lena = ip_bits(ipa);
lenb = ip_bits(ipb);
len = ip_addrsize(ipa);
/* apply the network mask to both addresses */
for (i = 0; i < len; i++)
{
unsigned char mask;
int nbits;
nbits = lena - (i * 8);
if (nbits < 8)
{
mask = (0xFF << (8 - nbits));
addra[i] = (addra[i] & mask);
}
nbits = lenb - (i * 8);
if (nbits < 8)
{
mask = (0xFF << (8 - nbits));
addrb[i] = (addrb[i] & mask);
}
}
/* Calculate the difference between the addresses. */
delta = 0;
for (i = len - 1; i >= 0; i--)
{
unsigned char a = addra[i];
unsigned char b = addrb[i];
delta += (float8) b - (float8) a;
delta /= 256;
}
Assert((delta >= 0) && (delta <= 1));
pfree(addra);
pfree(addrb);
PG_RETURN_FLOAT8(delta);
}
static void
brin_minmax_multi_serialize(BrinDesc *bdesc, Datum src, Datum *dst)
{
Ranges *ranges = (Ranges *) DatumGetPointer(src);
SerializedRanges *s;
/*
* In batch mode, we need to compress the accumulated values to the
* actually requested number of values/ranges.
*/
compactify_ranges(bdesc, ranges, ranges->target_maxvalues);
/* At this point everything has to be fully sorted. */
Assert(ranges->nsorted == ranges->nvalues);
s = brin_range_serialize(ranges);
dst[0] = PointerGetDatum(s);
}
static int
brin_minmax_multi_get_values(BrinDesc *bdesc, MinMaxMultiOptions *opts)
{
return MinMaxMultiGetValuesPerRange(opts);
}
/*
* Examine the given index tuple (which contains the partial status of a
* certain page range) by comparing it to the given value that comes from
* another heap tuple. If the new value is outside the min/max range
* specified by the existing tuple values, update the index tuple and return
* true. Otherwise, return false and do not modify in this case.
*/
Datum
brin_minmax_multi_add_value(PG_FUNCTION_ARGS)
{
BrinDesc *bdesc = (BrinDesc *) PG_GETARG_POINTER(0);
BrinValues *column = (BrinValues *) PG_GETARG_POINTER(1);
Datum newval = PG_GETARG_DATUM(2);
bool isnull PG_USED_FOR_ASSERTS_ONLY = PG_GETARG_DATUM(3);
MinMaxMultiOptions *opts = (MinMaxMultiOptions *) PG_GET_OPCLASS_OPTIONS();
Oid colloid = PG_GET_COLLATION();
bool modified = false;
Form_pg_attribute attr;
AttrNumber attno;
Ranges *ranges;
SerializedRanges *serialized = NULL;
Assert(!isnull);
attno = column->bv_attno;
attr = TupleDescAttr(bdesc->bd_tupdesc, attno - 1);
/* use the already deserialized value, if possible */
ranges = (Ranges *) DatumGetPointer(column->bv_mem_value);
/*
* If this is the first non-null value, we need to initialize the range
* list. Otherwise, just extract the existing range list from BrinValues.
*
* When starting with an empty range, we assume this is a batch mode and
* we use a larger buffer. The buffer size is derived from the BRIN range
* size, number of rows per page, with some sensible min/max values. A
* small buffer would be bad for performance, but a large buffer might
* require a lot of memory (because of keeping all the values).
*/
if (column->bv_allnulls)
{
MemoryContext oldctx;
int target_maxvalues;
int maxvalues;
BlockNumber pagesPerRange = BrinGetPagesPerRange(bdesc->bd_index);
/* what was specified as a reloption? */
target_maxvalues = brin_minmax_multi_get_values(bdesc, opts);
/*
* Determine the insert buffer size - we use 10x the target, capped to
* the maximum number of values in the heap range. This is more than
* enough, considering the actual number of rows per page is likely
* much lower, but meh.
*/
maxvalues = Min(target_maxvalues * MINMAX_BUFFER_FACTOR,
MaxHeapTuplesPerPage * pagesPerRange);
/* but always at least the original value */
maxvalues = Max(maxvalues, target_maxvalues);
/* always cap by MIN/MAX */
maxvalues = Max(maxvalues, MINMAX_BUFFER_MIN);
maxvalues = Min(maxvalues, MINMAX_BUFFER_MAX);
oldctx = MemoryContextSwitchTo(column->bv_context);
ranges = minmax_multi_init(maxvalues);
ranges->attno = attno;
ranges->colloid = colloid;
ranges->typid = attr->atttypid;
ranges->target_maxvalues = target_maxvalues;
/* we'll certainly need the comparator, so just look it up now */
ranges->cmp = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid,
BTLessStrategyNumber);
MemoryContextSwitchTo(oldctx);
column->bv_allnulls = false;
modified = true;
column->bv_mem_value = PointerGetDatum(ranges);
column->bv_serialize = brin_minmax_multi_serialize;
}
else if (!ranges)
{
MemoryContext oldctx;
int maxvalues;
BlockNumber pagesPerRange = BrinGetPagesPerRange(bdesc->bd_index);
oldctx = MemoryContextSwitchTo(column->bv_context);
serialized = (SerializedRanges *) PG_DETOAST_DATUM(column->bv_values[0]);
/*
* Determine the insert buffer size - we use 10x the target, capped to
* the maximum number of values in the heap range. This is more than
* enough, considering the actual number of rows per page is likely
* much lower, but meh.
*/
maxvalues = Min(serialized->maxvalues * MINMAX_BUFFER_FACTOR,
MaxHeapTuplesPerPage * pagesPerRange);
/* but always at least the original value */
maxvalues = Max(maxvalues, serialized->maxvalues);
/* always cap by MIN/MAX */
maxvalues = Max(maxvalues, MINMAX_BUFFER_MIN);
maxvalues = Min(maxvalues, MINMAX_BUFFER_MAX);
ranges = brin_range_deserialize(maxvalues, serialized);
ranges->attno = attno;
ranges->colloid = colloid;
ranges->typid = attr->atttypid;
/* we'll certainly need the comparator, so just look it up now */
ranges->cmp = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid,
BTLessStrategyNumber);
column->bv_mem_value = PointerGetDatum(ranges);
column->bv_serialize = brin_minmax_multi_serialize;
MemoryContextSwitchTo(oldctx);
}
/*
* Try to add the new value to the range. We need to update the modified
* flag, so that we serialize the updated summary later.
*/
modified |= range_add_value(bdesc, colloid, attno, attr, ranges, newval);
PG_RETURN_BOOL(modified);
}
/*
* Given an index tuple corresponding to a certain page range and a scan key,
* return whether the scan key is consistent with the index tuple's min/max
* values. Return true if so, false otherwise.
*/
Datum
brin_minmax_multi_consistent(PG_FUNCTION_ARGS)
{
BrinDesc *bdesc = (BrinDesc *) PG_GETARG_POINTER(0);
BrinValues *column = (BrinValues *) PG_GETARG_POINTER(1);
ScanKey *keys = (ScanKey *) PG_GETARG_POINTER(2);
int nkeys = PG_GETARG_INT32(3);
Oid colloid = PG_GET_COLLATION(),
subtype;
AttrNumber attno;
Datum value;
FmgrInfo *finfo;
SerializedRanges *serialized;
Ranges *ranges;
int keyno;
int rangeno;
int i;
attno = column->bv_attno;
serialized = (SerializedRanges *) PG_DETOAST_DATUM(column->bv_values[0]);
ranges = brin_range_deserialize(serialized->maxvalues, serialized);
/* inspect the ranges, and for each one evaluate the scan keys */
for (rangeno = 0; rangeno < ranges->nranges; rangeno++)
{
Datum minval = ranges->values[2 * rangeno];
Datum maxval = ranges->values[2 * rangeno + 1];
/* assume the range is matching, and we'll try to prove otherwise */
bool matching = true;
for (keyno = 0; keyno < nkeys; keyno++)
{
Datum matches;
ScanKey key = keys[keyno];
/* NULL keys are handled and filtered-out in bringetbitmap */
Assert(!(key->sk_flags & SK_ISNULL));
attno = key->sk_attno;
subtype = key->sk_subtype;
value = key->sk_argument;
switch (key->sk_strategy)
{
case BTLessStrategyNumber:
case BTLessEqualStrategyNumber:
finfo = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype,
key->sk_strategy);
/* first value from the array */
matches = FunctionCall2Coll(finfo, colloid, minval, value);
break;
case BTEqualStrategyNumber:
{
Datum compar;
FmgrInfo *cmpFn;
/* by default this range does not match */
matches = false;
/*
* Otherwise, need to compare the new value with
* boundaries of all the ranges. First check if it's
* less than the absolute minimum, which is the first
* value in the array.
*/
cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype,
BTGreaterStrategyNumber);
compar = FunctionCall2Coll(cmpFn, colloid, minval, value);
/* smaller than the smallest value in this range */
if (DatumGetBool(compar))
break;
cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype,
BTLessStrategyNumber);
compar = FunctionCall2Coll(cmpFn, colloid, maxval, value);
/* larger than the largest value in this range */
if (DatumGetBool(compar))
break;
/*
* We haven't managed to eliminate this range, so
* consider it matching.
*/
matches = true;
break;
}
case BTGreaterEqualStrategyNumber:
case BTGreaterStrategyNumber:
finfo = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype,
key->sk_strategy);
/* last value from the array */
matches = FunctionCall2Coll(finfo, colloid, maxval, value);
break;
default:
/* shouldn't happen */
elog(ERROR, "invalid strategy number %d", key->sk_strategy);
matches = 0;
break;
}
/* the range has to match all the scan keys */
matching &= DatumGetBool(matches);
/* once we find a non-matching key, we're done */
if (!matching)
break;
}
/*
* have we found a range matching all scan keys? if yes, we're done
*/
if (matching)
PG_RETURN_DATUM(BoolGetDatum(true));
}
/*
* And now inspect the values. We don't bother with doing a binary search
* here, because we're dealing with serialized / fully compacted ranges,
* so there should be only very few values.
*/
for (i = 0; i < ranges->nvalues; i++)
{
Datum val = ranges->values[2 * ranges->nranges + i];
/* assume the range is matching, and we'll try to prove otherwise */
bool matching = true;
for (keyno = 0; keyno < nkeys; keyno++)
{
Datum matches;
ScanKey key = keys[keyno];
/* we've already dealt with NULL keys at the beginning */
if (key->sk_flags & SK_ISNULL)
continue;
attno = key->sk_attno;
subtype = key->sk_subtype;
value = key->sk_argument;
switch (key->sk_strategy)
{
case BTLessStrategyNumber:
case BTLessEqualStrategyNumber:
case BTEqualStrategyNumber:
case BTGreaterEqualStrategyNumber:
case BTGreaterStrategyNumber:
finfo = minmax_multi_get_strategy_procinfo(bdesc, attno, subtype,
key->sk_strategy);
matches = FunctionCall2Coll(finfo, colloid, val, value);
break;
default:
/* shouldn't happen */
elog(ERROR, "invalid strategy number %d", key->sk_strategy);
matches = 0;
break;
}
/* the range has to match all the scan keys */
matching &= DatumGetBool(matches);
/* once we find a non-matching key, we're done */
if (!matching)
break;
}
/* have we found a range matching all scan keys? if yes, we're done */
if (matching)
PG_RETURN_DATUM(BoolGetDatum(true));
}
PG_RETURN_DATUM(BoolGetDatum(false));
}
/*
* Given two BrinValues, update the first of them as a union of the summary
* values contained in both. The second one is untouched.
*/
Datum
brin_minmax_multi_union(PG_FUNCTION_ARGS)
{
BrinDesc *bdesc = (BrinDesc *) PG_GETARG_POINTER(0);
BrinValues *col_a = (BrinValues *) PG_GETARG_POINTER(1);
BrinValues *col_b = (BrinValues *) PG_GETARG_POINTER(2);
Oid colloid = PG_GET_COLLATION();
SerializedRanges *serialized_a;
SerializedRanges *serialized_b;
Ranges *ranges_a;
Ranges *ranges_b;
AttrNumber attno;
Form_pg_attribute attr;
ExpandedRange *eranges;
int neranges;
FmgrInfo *cmpFn,
*distanceFn;
DistanceValue *distances;
MemoryContext ctx;
MemoryContext oldctx;
Assert(col_a->bv_attno == col_b->bv_attno);
Assert(!col_a->bv_allnulls && !col_b->bv_allnulls);
attno = col_a->bv_attno;
attr = TupleDescAttr(bdesc->bd_tupdesc, attno - 1);
serialized_a = (SerializedRanges *) PG_DETOAST_DATUM(col_a->bv_values[0]);
serialized_b = (SerializedRanges *) PG_DETOAST_DATUM(col_b->bv_values[0]);
ranges_a = brin_range_deserialize(serialized_a->maxvalues, serialized_a);
ranges_b = brin_range_deserialize(serialized_b->maxvalues, serialized_b);
/* make sure neither of the ranges is NULL */
Assert(ranges_a && ranges_b);
neranges = (ranges_a->nranges + ranges_a->nvalues) +
(ranges_b->nranges + ranges_b->nvalues);
/*
* The distanceFn calls (which may internally call e.g. numeric_le) may
* allocate quite a bit of memory, and we must not leak it. Otherwise,
* we'd have problems e.g. when building indexes. So we create a local
* memory context and make sure we free the memory before leaving this
* function (not after every call).
*/
ctx = AllocSetContextCreate(CurrentMemoryContext,
"minmax-multi context",
ALLOCSET_DEFAULT_SIZES);
oldctx = MemoryContextSwitchTo(ctx);
/* allocate and fill */
eranges = (ExpandedRange *) palloc0(neranges * sizeof(ExpandedRange));
/* fill the expanded ranges with entries for the first range */
fill_expanded_ranges(eranges, ranges_a->nranges + ranges_a->nvalues,
ranges_a);
/* and now add combine ranges for the second range */
fill_expanded_ranges(&eranges[ranges_a->nranges + ranges_a->nvalues],
ranges_b->nranges + ranges_b->nvalues,
ranges_b);
cmpFn = minmax_multi_get_strategy_procinfo(bdesc, attno, attr->atttypid,
BTLessStrategyNumber);
/* sort the expanded ranges */
neranges = sort_expanded_ranges(cmpFn, colloid, eranges, neranges);
/*
* We've loaded two different lists of expanded ranges, so some of them
* may be overlapping. So walk through them and merge them.
*/
neranges = merge_overlapping_ranges(cmpFn, colloid, eranges, neranges);
/* check that the combine ranges are correct (no overlaps, ordering) */
AssertCheckExpandedRanges(bdesc, colloid, attno, attr, eranges, neranges);
/*
* If needed, reduce some of the ranges.
*
* XXX This may be fairly expensive, so maybe we should do it only when
* it's actually needed (when we have too many ranges).
*/
/* build array of gap distances and sort them in ascending order */
distanceFn = minmax_multi_get_procinfo(bdesc, attno, PROCNUM_DISTANCE);
distances = build_distances(distanceFn, colloid, eranges, neranges);
/*
* See how many values would be needed to store the current ranges, and if
* needed combine as many of them to get below the threshold. The
* collapsed ranges will be stored as a single value.
*
* XXX This does not apply the load factor, as we don't expect to add more
* values to the range, so we prefer to keep as many ranges as possible.
*
* XXX Can the maxvalues be different in the two ranges? Perhaps we should
* use maximum of those?
*/
neranges = reduce_expanded_ranges(eranges, neranges, distances,
ranges_a->maxvalues,
cmpFn, colloid);
/* update the first range summary */
store_expanded_ranges(ranges_a, eranges, neranges);
MemoryContextSwitchTo(oldctx);
MemoryContextDelete(ctx);
/* cleanup and update the serialized value */
pfree(serialized_a);
col_a->bv_values[0] = PointerGetDatum(brin_range_serialize(ranges_a));
PG_RETURN_VOID();
}
/*
* Cache and return minmax multi opclass support procedure
*
* Return the procedure corresponding to the given function support number
* or null if it does not exist.
*/
static FmgrInfo *
minmax_multi_get_procinfo(BrinDesc *bdesc, uint16 attno, uint16 procnum)
{
MinmaxMultiOpaque *opaque;
uint16 basenum = procnum - PROCNUM_BASE;
/*
* We cache these in the opaque struct, to avoid repetitive syscache
* lookups.
*/
opaque = (MinmaxMultiOpaque *) bdesc->bd_info[attno - 1]->oi_opaque;
/*
* If we already searched for this proc and didn't find it, don't bother
* searching again.
*/
if (opaque->extra_proc_missing[basenum])
return NULL;
if (opaque->extra_procinfos[basenum].fn_oid == InvalidOid)
{
if (RegProcedureIsValid(index_getprocid(bdesc->bd_index, attno,
procnum)))
{
fmgr_info_copy(&opaque->extra_procinfos[basenum],
index_getprocinfo(bdesc->bd_index, attno, procnum),
bdesc->bd_context);
}
else
{
opaque->extra_proc_missing[basenum] = true;
return NULL;
}
}
return &opaque->extra_procinfos[basenum];
}
/*
* Cache and return the procedure for the given strategy.
*
* Note: this function mirrors minmax_multi_get_strategy_procinfo; see notes
* there. If changes are made here, see that function too.
*/
static FmgrInfo *
minmax_multi_get_strategy_procinfo(BrinDesc *bdesc, uint16 attno, Oid subtype,
uint16 strategynum)
{
MinmaxMultiOpaque *opaque;
Assert(strategynum >= 1 &&
strategynum <= BTMaxStrategyNumber);
opaque = (MinmaxMultiOpaque *) bdesc->bd_info[attno - 1]->oi_opaque;
/*
* We cache the procedures for the previous subtype in the opaque struct,
* to avoid repetitive syscache lookups. If the subtype changed,
* invalidate all the cached entries.
*/
if (opaque->cached_subtype != subtype)
{
uint16 i;
for (i = 1; i <= BTMaxStrategyNumber; i++)
opaque->strategy_procinfos[i - 1].fn_oid = InvalidOid;
opaque->cached_subtype = subtype;
}
if (opaque->strategy_procinfos[strategynum - 1].fn_oid == InvalidOid)
{
Form_pg_attribute attr;
HeapTuple tuple;
Oid opfamily,
oprid;
bool isNull;
opfamily = bdesc->bd_index->rd_opfamily[attno - 1];
attr = TupleDescAttr(bdesc->bd_tupdesc, attno - 1);
tuple = SearchSysCache4(AMOPSTRATEGY, ObjectIdGetDatum(opfamily),
ObjectIdGetDatum(attr->atttypid),
ObjectIdGetDatum(subtype),
Int16GetDatum(strategynum));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
strategynum, attr->atttypid, subtype, opfamily);
oprid = DatumGetObjectId(SysCacheGetAttr(AMOPSTRATEGY, tuple,
Anum_pg_amop_amopopr, &isNull));
ReleaseSysCache(tuple);
Assert(!isNull && RegProcedureIsValid(oprid));
fmgr_info_cxt(get_opcode(oprid),
&opaque->strategy_procinfos[strategynum - 1],
bdesc->bd_context);
}
return &opaque->strategy_procinfos[strategynum - 1];
}
Datum
brin_minmax_multi_options(PG_FUNCTION_ARGS)
{
local_relopts *relopts = (local_relopts *) PG_GETARG_POINTER(0);
init_local_reloptions(relopts, sizeof(MinMaxMultiOptions));
add_local_int_reloption(relopts, "values_per_range", "desc",
MINMAX_MULTI_DEFAULT_VALUES_PER_PAGE, 8, 256,
offsetof(MinMaxMultiOptions, valuesPerRange));
PG_RETURN_VOID();
}
/*
* brin_minmax_multi_summary_in
* - input routine for type brin_minmax_multi_summary.
*
* brin_minmax_multi_summary is only used internally to represent summaries
* in BRIN minmax-multi indexes, so it has no operations of its own, and we
* disallow input too.
*/
Datum
brin_minmax_multi_summary_in(PG_FUNCTION_ARGS)
{
/*
* brin_minmax_multi_summary stores the data in binary form and parsing
* text input is not needed, so disallow this.
*/
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot accept a value of type %s", "brin_minmax_multi_summary")));
PG_RETURN_VOID(); /* keep compiler quiet */
}
/*
* brin_minmax_multi_summary_out
* - output routine for type brin_minmax_multi_summary.
*
* BRIN minmax-multi summaries are serialized into a bytea value, but we
* want to output something nicer humans can understand.
*/
Datum
brin_minmax_multi_summary_out(PG_FUNCTION_ARGS)
{
int i;
int idx;
SerializedRanges *ranges;
Ranges *ranges_deserialized;
StringInfoData str;
bool isvarlena;
Oid outfunc;
FmgrInfo fmgrinfo;
ArrayBuildState *astate_values = NULL;
initStringInfo(&str);
appendStringInfoChar(&str, '{');
/*
* Detoast to get value with full 4B header (can't be stored in a toast
* table, but can use 1B header).
*/
ranges = (SerializedRanges *) PG_DETOAST_DATUM_PACKED(PG_GETARG_DATUM(0));
/* lookup output func for the type */
getTypeOutputInfo(ranges->typid, &outfunc, &isvarlena);
fmgr_info(outfunc, &fmgrinfo);
/* deserialize the range info easy-to-process pieces */
ranges_deserialized = brin_range_deserialize(ranges->maxvalues, ranges);
appendStringInfo(&str, "nranges: %d nvalues: %d maxvalues: %d",
ranges_deserialized->nranges,
ranges_deserialized->nvalues,
ranges_deserialized->maxvalues);
/* serialize ranges */
idx = 0;
for (i = 0; i < ranges_deserialized->nranges; i++)
{
char *a,
*b;
text *c;
StringInfoData str;
initStringInfo(&str);
a = OutputFunctionCall(&fmgrinfo, ranges_deserialized->values[idx++]);
b = OutputFunctionCall(&fmgrinfo, ranges_deserialized->values[idx++]);
appendStringInfo(&str, "%s ... %s", a, b);
c = cstring_to_text_with_len(str.data, str.len);
astate_values = accumArrayResult(astate_values,
PointerGetDatum(c),
false,
TEXTOID,
CurrentMemoryContext);
}
if (ranges_deserialized->nranges > 0)
{
Oid typoutput;
bool typIsVarlena;
Datum val;
char *extval;
getTypeOutputInfo(ANYARRAYOID, &typoutput, &typIsVarlena);
val = makeArrayResult(astate_values, CurrentMemoryContext);
extval = OidOutputFunctionCall(typoutput, val);
appendStringInfo(&str, " ranges: %s", extval);
}
/* serialize individual values */
astate_values = NULL;
for (i = 0; i < ranges_deserialized->nvalues; i++)
{
Datum a;
text *b;
a = FunctionCall1(&fmgrinfo, ranges_deserialized->values[idx++]);
b = cstring_to_text(DatumGetCString(a));
astate_values = accumArrayResult(astate_values,
PointerGetDatum(b),
false,
TEXTOID,
CurrentMemoryContext);
}
if (ranges_deserialized->nvalues > 0)
{
Oid typoutput;
bool typIsVarlena;
Datum val;
char *extval;
getTypeOutputInfo(ANYARRAYOID, &typoutput, &typIsVarlena);
val = makeArrayResult(astate_values, CurrentMemoryContext);
extval = OidOutputFunctionCall(typoutput, val);
appendStringInfo(&str, " values: %s", extval);
}
appendStringInfoChar(&str, '}');
PG_RETURN_CSTRING(str.data);
}
/*
* brin_minmax_multi_summary_recv
* - binary input routine for type brin_minmax_multi_summary.
*/
Datum
brin_minmax_multi_summary_recv(PG_FUNCTION_ARGS)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot accept a value of type %s", "brin_minmax_multi_summary")));
PG_RETURN_VOID(); /* keep compiler quiet */
}
/*
* brin_minmax_multi_summary_send
* - binary output routine for type brin_minmax_multi_summary.
*
* BRIN minmax-multi summaries are serialized in a bytea value (although
* the type is named differently), so let's just send that.
*/
Datum
brin_minmax_multi_summary_send(PG_FUNCTION_ARGS)
{
return byteasend(fcinfo);
}
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