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/*-
* Copyright (c) 2008-2012 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#define WT_BTREE_MAJOR_VERSION 1 /* Version */
#define WT_BTREE_MINOR_VERSION 0
/*
* The minimum btree leaf and internal page sizes are 512B, the maximum 512MB.
* (The maximum of 512MB is enforced by the software, it could be set as high
* as 4GB.)
*/
#define WT_BTREE_ALLOCATION_SIZE_MIN 512
#define WT_BTREE_ALLOCATION_SIZE_MAX (128 * WT_MEGABYTE)
#define WT_BTREE_PAGE_SIZE_MAX (512 * WT_MEGABYTE)
/*
* Variable-length value items and row-store key/value item lengths are stored
* in 32-bit unsigned integers, meaning the largest theoretical key/value item
* is 4GB. However, in the WT_UPDATE structure we use the UINT32_MAX size as a
* "deleted" flag. Limit the size of a single object to 4GB - 512B: it's a few
* additional bytes if we ever want to store a small structure length plus the
* object size in 32 bits, or if we ever need more denoted values. Storing 4GB
* objects in a Btree borders on clinical insanity, anyway.
*
* Record numbers are stored in 64-bit unsigned integers, meaning the largest
* record number is "really, really big".
*/
#define WT_BTREE_MAX_OBJECT_SIZE (UINT32_MAX - 512)
/*
* A location in a file is a variable-length cookie, but it has a maximum size
* so it's easy to create temporary space in which to store them. (Locations
* can't be much larger than this anyway, they must fit onto the minimum size
* page because a reference to an overflow page is itself a location.)
*/
#define WT_BTREE_MAX_ADDR_COOKIE 255 /* Maximum address cookie */
/*
* Split page size calculation -- we don't want to repeatedly split every time
* a new entry is added, so we split to a smaller-than-maximum page size.
*/
#define WT_SPLIT_PAGE_SIZE(pagesize, allocsize, pct) \
WT_ALIGN(((uintmax_t)(pagesize) * (pct)) / 100, allocsize)
/*
* XXX
* The server threads use their own WT_SESSION_IMPL handles because they may
* want to block (for example, the eviction server calls reconciliation, and
* some of the reconciliation diagnostic code reads pages), and the user's
* session handle is already blocking on a server thread. The problem is the
* server thread needs to reference the correct btree handle, and that's
* hanging off the application's thread of control. For now, I'm just making
* it obvious where that's getting done.
*/
#define WT_SET_BTREE_IN_SESSION(s, b) ((s)->btree = (b))
#define WT_CLEAR_BTREE_IN_SESSION(s) ((s)->btree = NULL)
/*
* WT_BTREE --
* A btree handle.
*/
struct __wt_btree {
WT_RWLOCK *rwlock; /* Lock for shared/exclusive ops */
uint32_t refcnt; /* Sessions using this tree. */
TAILQ_ENTRY(__wt_btree) q; /* Linked list of handles */
const char *name; /* Object name as a URI */
const char *checkpoint; /* Checkpoint name (or NULL) */
const char *config; /* Configuration string */
WT_DSRC_STATS *stats; /* Data-source statistics */
/*
* XXX Everything above here should move into the session-level
* handle structure.
*/
WT_CKPT *ckpt; /* Checkpoint information */
enum { BTREE_COL_FIX=1, /* Fixed-length column store */
BTREE_COL_VAR=2, /* Variable-length column store */
BTREE_ROW=3 /* Row-store */
} type; /* Type */
const char *key_format; /* Key format */
const char *value_format; /* Value format */
uint8_t bitcnt; /* Fixed-length field size in bits */
/* Row-store comparison function */
WT_COLLATOR *collator; /* Comparison function */
uint32_t key_gap; /* Row-store prefix key gap */
uint32_t allocsize; /* Allocation size */
uint32_t maxintlpage; /* Internal page max size */
uint32_t maxintlitem; /* Internal page max item size */
uint32_t maxleafpage; /* Leaf page max size */
uint32_t maxleafitem; /* Leaf page max item size */
void *huffman_key; /* Key huffman encoding */
void *huffman_value; /* Value huffman encoding */
enum { CKSUM_ON=1, /* On */
CKSUM_OFF=2, /* Off */
CKSUM_UNCOMPRESSED=3 /* Uncompressed blocks only */
} checksum; /* Checksum configuration */
u_int dictionary; /* Reconcile: dictionary slots */
int internal_key_truncate; /* Reconcile: internal key truncate */
int prefix_compression; /* Reconcile: key prefix compression */
u_int split_pct; /* Reconcile: split page percent */
WT_COMPRESSOR *compressor; /* Reconcile: page compressor */
WT_RWLOCK *val_ovfl_lock; /* Reconcile: overflow value lock */
uint64_t last_recno; /* Column-store last record number */
WT_PAGE *root_page; /* Root page */
int modified; /* If the tree ever modified */
int bulk_load_ok; /* Bulk-load is a possibility */
void *block; /* Block manager */
u_int block_header; /* Block manager header length */
uint64_t write_gen; /* Write generation */
WT_PAGE *evict_page; /* Eviction thread's location */
uint64_t evict_priority; /* Relative priority of cached pages. */
volatile uint32_t lru_count; /* Count of threads in LRU eviction */
#define WT_BTREE_BULK 0x0001 /* Bulk-load handle */
#define WT_BTREE_DISCARD 0x0002 /* Discard on release */
#define WT_BTREE_EXCLUSIVE 0x0004 /* Need exclusive access to handle */
#define WT_BTREE_LOCK_ONLY 0x0008 /* Handle is only needed for locking */
#define WT_BTREE_NO_CACHE 0x0010 /* Disable caching */
#define WT_BTREE_NO_EVICTION 0x0020 /* Disable eviction */
#define WT_BTREE_NO_HAZARD 0x0040 /* Disable hazard pointers */
#define WT_BTREE_OPEN 0x0080 /* Handle is open */
#define WT_BTREE_SALVAGE 0x0100 /* Handle is for salvage */
#define WT_BTREE_UPGRADE 0x0200 /* Handle is for upgrade */
#define WT_BTREE_VERIFY 0x0400 /* Handle is for verify */
uint32_t flags;
};
/* Flags that make a btree handle special (not for normal use). */
#define WT_BTREE_SPECIAL_FLAGS \
(WT_BTREE_BULK | WT_BTREE_NO_CACHE | \
WT_BTREE_SALVAGE | WT_BTREE_UPGRADE | WT_BTREE_VERIFY)
/*
* WT_SALVAGE_COOKIE --
* Encapsulation of salvage information for reconciliation.
*/
struct __wt_salvage_cookie {
uint64_t missing; /* Initial items to create */
uint64_t skip; /* Initial items to skip */
uint64_t take; /* Items to take */
int done; /* Ignore the rest */
};
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