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|
/*-------------------------------------------------------------------------
*
* ginutil.c
* Utility routines for the Postgres inverted index access method.
*
*
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/access/gin/ginutil.c
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/gin_private.h"
#include "access/ginxlog.h"
#include "access/reloptions.h"
#include "access/xloginsert.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_type.h"
#include "miscadmin.h"
#include "storage/indexfsm.h"
#include "storage/lmgr.h"
#include "utils/builtins.h"
#include "utils/index_selfuncs.h"
#include "utils/typcache.h"
/*
* GIN handler function: return IndexAmRoutine with access method parameters
* and callbacks.
*/
Datum
ginhandler(PG_FUNCTION_ARGS)
{
IndexAmRoutine *amroutine = makeNode(IndexAmRoutine);
amroutine->amstrategies = 0;
amroutine->amsupport = GINNProcs;
amroutine->amcanorder = false;
amroutine->amcanorderbyop = false;
amroutine->amcanbackward = false;
amroutine->amcanunique = false;
amroutine->amcanmulticol = true;
amroutine->amoptionalkey = true;
amroutine->amsearcharray = false;
amroutine->amsearchnulls = false;
amroutine->amstorage = true;
amroutine->amclusterable = false;
amroutine->ampredlocks = false;
amroutine->amcanparallel = false;
amroutine->amkeytype = InvalidOid;
amroutine->ambuild = ginbuild;
amroutine->ambuildempty = ginbuildempty;
amroutine->aminsert = gininsert;
amroutine->ambulkdelete = ginbulkdelete;
amroutine->amvacuumcleanup = ginvacuumcleanup;
amroutine->amcanreturn = NULL;
amroutine->amcostestimate = gincostestimate;
amroutine->amoptions = ginoptions;
amroutine->amproperty = NULL;
amroutine->amvalidate = ginvalidate;
amroutine->ambeginscan = ginbeginscan;
amroutine->amrescan = ginrescan;
amroutine->amgettuple = NULL;
amroutine->amgetbitmap = gingetbitmap;
amroutine->amendscan = ginendscan;
amroutine->ammarkpos = NULL;
amroutine->amrestrpos = NULL;
amroutine->amestimateparallelscan = NULL;
amroutine->aminitparallelscan = NULL;
amroutine->amparallelrescan = NULL;
PG_RETURN_POINTER(amroutine);
}
/*
* initGinState: fill in an empty GinState struct to describe the index
*
* Note: assorted subsidiary data is allocated in the CurrentMemoryContext.
*/
void
initGinState(GinState *state, Relation index)
{
TupleDesc origTupdesc = RelationGetDescr(index);
int i;
MemSet(state, 0, sizeof(GinState));
state->index = index;
state->oneCol = (origTupdesc->natts == 1) ? true : false;
state->origTupdesc = origTupdesc;
for (i = 0; i < origTupdesc->natts; i++)
{
Form_pg_attribute attr = TupleDescAttr(origTupdesc, i);
if (state->oneCol)
state->tupdesc[i] = state->origTupdesc;
else
{
state->tupdesc[i] = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(state->tupdesc[i], (AttrNumber) 1, NULL,
INT2OID, -1, 0);
TupleDescInitEntry(state->tupdesc[i], (AttrNumber) 2, NULL,
attr->atttypid,
attr->atttypmod,
attr->attndims);
TupleDescInitEntryCollation(state->tupdesc[i], (AttrNumber) 2,
attr->attcollation);
}
/*
* If the compare proc isn't specified in the opclass definition, look
* up the index key type's default btree comparator.
*/
if (index_getprocid(index, i + 1, GIN_COMPARE_PROC) != InvalidOid)
{
fmgr_info_copy(&(state->compareFn[i]),
index_getprocinfo(index, i + 1, GIN_COMPARE_PROC),
CurrentMemoryContext);
}
else
{
TypeCacheEntry *typentry;
typentry = lookup_type_cache(attr->atttypid,
TYPECACHE_CMP_PROC_FINFO);
if (!OidIsValid(typentry->cmp_proc_finfo.fn_oid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("could not identify a comparison function for type %s",
format_type_be(attr->atttypid))));
fmgr_info_copy(&(state->compareFn[i]),
&(typentry->cmp_proc_finfo),
CurrentMemoryContext);
}
/* Opclass must always provide extract procs */
fmgr_info_copy(&(state->extractValueFn[i]),
index_getprocinfo(index, i + 1, GIN_EXTRACTVALUE_PROC),
CurrentMemoryContext);
fmgr_info_copy(&(state->extractQueryFn[i]),
index_getprocinfo(index, i + 1, GIN_EXTRACTQUERY_PROC),
CurrentMemoryContext);
/*
* Check opclass capability to do tri-state or binary logic consistent
* check.
*/
if (index_getprocid(index, i + 1, GIN_TRICONSISTENT_PROC) != InvalidOid)
{
fmgr_info_copy(&(state->triConsistentFn[i]),
index_getprocinfo(index, i + 1, GIN_TRICONSISTENT_PROC),
CurrentMemoryContext);
}
if (index_getprocid(index, i + 1, GIN_CONSISTENT_PROC) != InvalidOid)
{
fmgr_info_copy(&(state->consistentFn[i]),
index_getprocinfo(index, i + 1, GIN_CONSISTENT_PROC),
CurrentMemoryContext);
}
if (state->consistentFn[i].fn_oid == InvalidOid &&
state->triConsistentFn[i].fn_oid == InvalidOid)
{
elog(ERROR, "missing GIN support function (%d or %d) for attribute %d of index \"%s\"",
GIN_CONSISTENT_PROC, GIN_TRICONSISTENT_PROC,
i + 1, RelationGetRelationName(index));
}
/*
* Check opclass capability to do partial match.
*/
if (index_getprocid(index, i + 1, GIN_COMPARE_PARTIAL_PROC) != InvalidOid)
{
fmgr_info_copy(&(state->comparePartialFn[i]),
index_getprocinfo(index, i + 1, GIN_COMPARE_PARTIAL_PROC),
CurrentMemoryContext);
state->canPartialMatch[i] = true;
}
else
{
state->canPartialMatch[i] = false;
}
/*
* If the index column has a specified collation, we should honor that
* while doing comparisons. However, we may have a collatable storage
* type for a noncollatable indexed data type (for instance, hstore
* uses text index entries). If there's no index collation then
* specify default collation in case the support functions need
* collation. This is harmless if the support functions don't care
* about collation, so we just do it unconditionally. (We could
* alternatively call get_typcollation, but that seems like expensive
* overkill --- there aren't going to be any cases where a GIN storage
* type has a nondefault collation.)
*/
if (OidIsValid(index->rd_indcollation[i]))
state->supportCollation[i] = index->rd_indcollation[i];
else
state->supportCollation[i] = DEFAULT_COLLATION_OID;
}
}
/*
* Extract attribute (column) number of stored entry from GIN tuple
*/
OffsetNumber
gintuple_get_attrnum(GinState *ginstate, IndexTuple tuple)
{
OffsetNumber colN;
if (ginstate->oneCol)
{
/* column number is not stored explicitly */
colN = FirstOffsetNumber;
}
else
{
Datum res;
bool isnull;
/*
* First attribute is always int16, so we can safely use any tuple
* descriptor to obtain first attribute of tuple
*/
res = index_getattr(tuple, FirstOffsetNumber, ginstate->tupdesc[0],
&isnull);
Assert(!isnull);
colN = DatumGetUInt16(res);
Assert(colN >= FirstOffsetNumber && colN <= ginstate->origTupdesc->natts);
}
return colN;
}
/*
* Extract stored datum (and possible null category) from GIN tuple
*/
Datum
gintuple_get_key(GinState *ginstate, IndexTuple tuple,
GinNullCategory *category)
{
Datum res;
bool isnull;
if (ginstate->oneCol)
{
/*
* Single column index doesn't store attribute numbers in tuples
*/
res = index_getattr(tuple, FirstOffsetNumber, ginstate->origTupdesc,
&isnull);
}
else
{
/*
* Since the datum type depends on which index column it's from, we
* must be careful to use the right tuple descriptor here.
*/
OffsetNumber colN = gintuple_get_attrnum(ginstate, tuple);
res = index_getattr(tuple, OffsetNumberNext(FirstOffsetNumber),
ginstate->tupdesc[colN - 1],
&isnull);
}
if (isnull)
*category = GinGetNullCategory(tuple, ginstate);
else
*category = GIN_CAT_NORM_KEY;
return res;
}
/*
* Allocate a new page (either by recycling, or by extending the index file)
* The returned buffer is already pinned and exclusive-locked
* Caller is responsible for initializing the page by calling GinInitBuffer
*/
Buffer
GinNewBuffer(Relation index)
{
Buffer buffer;
bool needLock;
/* First, try to get a page from FSM */
for (;;)
{
BlockNumber blkno = GetFreeIndexPage(index);
if (blkno == InvalidBlockNumber)
break;
buffer = ReadBuffer(index, blkno);
/*
* We have to guard against the possibility that someone else already
* recycled this page; the buffer may be locked if so.
*/
if (ConditionalLockBuffer(buffer))
{
Page page = BufferGetPage(buffer);
if (PageIsNew(page))
return buffer; /* OK to use, if never initialized */
if (GinPageIsDeleted(page))
return buffer; /* OK to use */
LockBuffer(buffer, GIN_UNLOCK);
}
/* Can't use it, so release buffer and try again */
ReleaseBuffer(buffer);
}
/* Must extend the file */
needLock = !RELATION_IS_LOCAL(index);
if (needLock)
LockRelationForExtension(index, ExclusiveLock);
buffer = ReadBuffer(index, P_NEW);
LockBuffer(buffer, GIN_EXCLUSIVE);
if (needLock)
UnlockRelationForExtension(index, ExclusiveLock);
return buffer;
}
void
GinInitPage(Page page, uint32 f, Size pageSize)
{
GinPageOpaque opaque;
PageInit(page, pageSize, sizeof(GinPageOpaqueData));
opaque = GinPageGetOpaque(page);
memset(opaque, 0, sizeof(GinPageOpaqueData));
opaque->flags = f;
opaque->rightlink = InvalidBlockNumber;
}
void
GinInitBuffer(Buffer b, uint32 f)
{
GinInitPage(BufferGetPage(b), f, BufferGetPageSize(b));
}
void
GinInitMetabuffer(Buffer b)
{
GinMetaPageData *metadata;
Page page = BufferGetPage(b);
GinInitPage(page, GIN_META, BufferGetPageSize(b));
metadata = GinPageGetMeta(page);
metadata->head = metadata->tail = InvalidBlockNumber;
metadata->tailFreeSize = 0;
metadata->nPendingPages = 0;
metadata->nPendingHeapTuples = 0;
metadata->nTotalPages = 0;
metadata->nEntryPages = 0;
metadata->nDataPages = 0;
metadata->nEntries = 0;
metadata->ginVersion = GIN_CURRENT_VERSION;
/*
* Set pd_lower just past the end of the metadata. This is essential,
* because without doing so, metadata will be lost if xlog.c compresses
* the page.
*/
((PageHeader) page)->pd_lower =
((char *) metadata + sizeof(GinMetaPageData)) - (char *) page;
}
/*
* Compare two keys of the same index column
*/
int
ginCompareEntries(GinState *ginstate, OffsetNumber attnum,
Datum a, GinNullCategory categorya,
Datum b, GinNullCategory categoryb)
{
/* if not of same null category, sort by that first */
if (categorya != categoryb)
return (categorya < categoryb) ? -1 : 1;
/* all null items in same category are equal */
if (categorya != GIN_CAT_NORM_KEY)
return 0;
/* both not null, so safe to call the compareFn */
return DatumGetInt32(FunctionCall2Coll(&ginstate->compareFn[attnum - 1],
ginstate->supportCollation[attnum - 1],
a, b));
}
/*
* Compare two keys of possibly different index columns
*/
int
ginCompareAttEntries(GinState *ginstate,
OffsetNumber attnuma, Datum a, GinNullCategory categorya,
OffsetNumber attnumb, Datum b, GinNullCategory categoryb)
{
/* attribute number is the first sort key */
if (attnuma != attnumb)
return (attnuma < attnumb) ? -1 : 1;
return ginCompareEntries(ginstate, attnuma, a, categorya, b, categoryb);
}
/*
* Support for sorting key datums in ginExtractEntries
*
* Note: we only have to worry about null and not-null keys here;
* ginExtractEntries never generates more than one placeholder null,
* so it doesn't have to sort those.
*/
typedef struct
{
Datum datum;
bool isnull;
} keyEntryData;
typedef struct
{
FmgrInfo *cmpDatumFunc;
Oid collation;
bool haveDups;
} cmpEntriesArg;
static int
cmpEntries(const void *a, const void *b, void *arg)
{
const keyEntryData *aa = (const keyEntryData *) a;
const keyEntryData *bb = (const keyEntryData *) b;
cmpEntriesArg *data = (cmpEntriesArg *) arg;
int res;
if (aa->isnull)
{
if (bb->isnull)
res = 0; /* NULL "=" NULL */
else
res = 1; /* NULL ">" not-NULL */
}
else if (bb->isnull)
res = -1; /* not-NULL "<" NULL */
else
res = DatumGetInt32(FunctionCall2Coll(data->cmpDatumFunc,
data->collation,
aa->datum, bb->datum));
/*
* Detect if we have any duplicates. If there are equal keys, qsort must
* compare them at some point, else it wouldn't know whether one should go
* before or after the other.
*/
if (res == 0)
data->haveDups = true;
return res;
}
/*
* Extract the index key values from an indexable item
*
* The resulting key values are sorted, and any duplicates are removed.
* This avoids generating redundant index entries.
*/
Datum *
ginExtractEntries(GinState *ginstate, OffsetNumber attnum,
Datum value, bool isNull,
int32 *nentries, GinNullCategory **categories)
{
Datum *entries;
bool *nullFlags;
int32 i;
/*
* We don't call the extractValueFn on a null item. Instead generate a
* placeholder.
*/
if (isNull)
{
*nentries = 1;
entries = (Datum *) palloc(sizeof(Datum));
entries[0] = (Datum) 0;
*categories = (GinNullCategory *) palloc(sizeof(GinNullCategory));
(*categories)[0] = GIN_CAT_NULL_ITEM;
return entries;
}
/* OK, call the opclass's extractValueFn */
nullFlags = NULL; /* in case extractValue doesn't set it */
entries = (Datum *)
DatumGetPointer(FunctionCall3Coll(&ginstate->extractValueFn[attnum - 1],
ginstate->supportCollation[attnum - 1],
value,
PointerGetDatum(nentries),
PointerGetDatum(&nullFlags)));
/*
* Generate a placeholder if the item contained no keys.
*/
if (entries == NULL || *nentries <= 0)
{
*nentries = 1;
entries = (Datum *) palloc(sizeof(Datum));
entries[0] = (Datum) 0;
*categories = (GinNullCategory *) palloc(sizeof(GinNullCategory));
(*categories)[0] = GIN_CAT_EMPTY_ITEM;
return entries;
}
/*
* If the extractValueFn didn't create a nullFlags array, create one,
* assuming that everything's non-null. Otherwise, run through the array
* and make sure each value is exactly 0 or 1; this ensures binary
* compatibility with the GinNullCategory representation.
*/
if (nullFlags == NULL)
nullFlags = (bool *) palloc0(*nentries * sizeof(bool));
else
{
for (i = 0; i < *nentries; i++)
nullFlags[i] = (nullFlags[i] ? true : false);
}
/* now we can use the nullFlags as category codes */
*categories = (GinNullCategory *) nullFlags;
/*
* If there's more than one key, sort and unique-ify.
*
* XXX Using qsort here is notationally painful, and the overhead is
* pretty bad too. For small numbers of keys it'd likely be better to use
* a simple insertion sort.
*/
if (*nentries > 1)
{
keyEntryData *keydata;
cmpEntriesArg arg;
keydata = (keyEntryData *) palloc(*nentries * sizeof(keyEntryData));
for (i = 0; i < *nentries; i++)
{
keydata[i].datum = entries[i];
keydata[i].isnull = nullFlags[i];
}
arg.cmpDatumFunc = &ginstate->compareFn[attnum - 1];
arg.collation = ginstate->supportCollation[attnum - 1];
arg.haveDups = false;
qsort_arg(keydata, *nentries, sizeof(keyEntryData),
cmpEntries, (void *) &arg);
if (arg.haveDups)
{
/* there are duplicates, must get rid of 'em */
int32 j;
entries[0] = keydata[0].datum;
nullFlags[0] = keydata[0].isnull;
j = 1;
for (i = 1; i < *nentries; i++)
{
if (cmpEntries(&keydata[i - 1], &keydata[i], &arg) != 0)
{
entries[j] = keydata[i].datum;
nullFlags[j] = keydata[i].isnull;
j++;
}
}
*nentries = j;
}
else
{
/* easy, no duplicates */
for (i = 0; i < *nentries; i++)
{
entries[i] = keydata[i].datum;
nullFlags[i] = keydata[i].isnull;
}
}
pfree(keydata);
}
return entries;
}
bytea *
ginoptions(Datum reloptions, bool validate)
{
relopt_value *options;
GinOptions *rdopts;
int numoptions;
static const relopt_parse_elt tab[] = {
{"fastupdate", RELOPT_TYPE_BOOL, offsetof(GinOptions, useFastUpdate)},
{"gin_pending_list_limit", RELOPT_TYPE_INT, offsetof(GinOptions,
pendingListCleanupSize)}
};
options = parseRelOptions(reloptions, validate, RELOPT_KIND_GIN,
&numoptions);
/* if none set, we're done */
if (numoptions == 0)
return NULL;
rdopts = allocateReloptStruct(sizeof(GinOptions), options, numoptions);
fillRelOptions((void *) rdopts, sizeof(GinOptions), options, numoptions,
validate, tab, lengthof(tab));
pfree(options);
return (bytea *) rdopts;
}
/*
* Fetch index's statistical data into *stats
*
* Note: in the result, nPendingPages can be trusted to be up-to-date,
* as can ginVersion; but the other fields are as of the last VACUUM.
*/
void
ginGetStats(Relation index, GinStatsData *stats)
{
Buffer metabuffer;
Page metapage;
GinMetaPageData *metadata;
metabuffer = ReadBuffer(index, GIN_METAPAGE_BLKNO);
LockBuffer(metabuffer, GIN_SHARE);
metapage = BufferGetPage(metabuffer);
metadata = GinPageGetMeta(metapage);
stats->nPendingPages = metadata->nPendingPages;
stats->nTotalPages = metadata->nTotalPages;
stats->nEntryPages = metadata->nEntryPages;
stats->nDataPages = metadata->nDataPages;
stats->nEntries = metadata->nEntries;
stats->ginVersion = metadata->ginVersion;
UnlockReleaseBuffer(metabuffer);
}
/*
* Write the given statistics to the index's metapage
*
* Note: nPendingPages and ginVersion are *not* copied over
*/
void
ginUpdateStats(Relation index, const GinStatsData *stats)
{
Buffer metabuffer;
Page metapage;
GinMetaPageData *metadata;
metabuffer = ReadBuffer(index, GIN_METAPAGE_BLKNO);
LockBuffer(metabuffer, GIN_EXCLUSIVE);
metapage = BufferGetPage(metabuffer);
metadata = GinPageGetMeta(metapage);
START_CRIT_SECTION();
metadata->nTotalPages = stats->nTotalPages;
metadata->nEntryPages = stats->nEntryPages;
metadata->nDataPages = stats->nDataPages;
metadata->nEntries = stats->nEntries;
/*
* Set pd_lower just past the end of the metadata. This is essential,
* because without doing so, metadata will be lost if xlog.c compresses
* the page. (We must do this here because pre-v11 versions of PG did not
* set the metapage's pd_lower correctly, so a pg_upgraded index might
* contain the wrong value.)
*/
((PageHeader) metapage)->pd_lower =
((char *) metadata + sizeof(GinMetaPageData)) - (char *) metapage;
MarkBufferDirty(metabuffer);
if (RelationNeedsWAL(index))
{
XLogRecPtr recptr;
ginxlogUpdateMeta data;
data.node = index->rd_node;
data.ntuples = 0;
data.newRightlink = data.prevTail = InvalidBlockNumber;
memcpy(&data.metadata, metadata, sizeof(GinMetaPageData));
XLogBeginInsert();
XLogRegisterData((char *) &data, sizeof(ginxlogUpdateMeta));
XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_UPDATE_META_PAGE);
PageSetLSN(metapage, recptr);
}
UnlockReleaseBuffer(metabuffer);
END_CRIT_SECTION();
}
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