/*- * Copyright (c) 2014-present MongoDB, Inc. * Copyright (c) 2008-2014 WiredTiger, Inc. * All rights reserved. * * See the file LICENSE for redistribution information. */ #pragma once /* * Supported btree formats: the "current" version is the maximum supported major/minor versions. */ #define WT_BTREE_VERSION_MIN ((WT_BTREE_VERSION){1, 1, 0}) /* Oldest version supported */ /* Increase the version number for standalone build. */ #ifdef WT_STANDALONE_BUILD #define WT_BTREE_VERSION_MAX ((WT_BTREE_VERSION){2, 1, 0}) /* Newest version supported */ #else #define WT_BTREE_VERSION_MAX ((WT_BTREE_VERSION){1, 1, 0}) /* Newest version supported */ #endif #define WT_BTREE_MIN_ALLOC_SIZE 512 /* * The maximum btree leaf and internal page size is 512MB (2^29). The limit is enforced in software, * it could be larger, specifically, the underlying default block manager can support 4GB (2^32). * Currently, the maximum page size must accommodate our dependence on the maximum page size fitting * into a number of bits less than 32; see the row-store page key-lookup functions for the magic. */ #define WT_BTREE_PAGE_SIZE_MAX (512 * WT_MEGABYTE) /* * The length of variable-length column-store values and row-store keys/values are stored in a 4B * type, so the largest theoretical key/value item is 4GB. However, in the WT_UPDATE structure we * use the UINT32_MAX size as a "deleted" flag, and second, the size of an overflow object is * constrained by what an underlying block manager can actually write. (For example, in the default * block manager, writing an overflow item includes the underlying block's page header and block * manager specific structure, aligned to an allocation-sized unit). The btree engine limits the * size of a single object to (4GB - 1KB); that gives us additional bytes if we ever want to store a * structure length plus the object size in 4B, or if we need additional flag values. Attempts to * store large key/value items in the tree trigger an immediate check to the block manager, to make * sure it can write the item. 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_t)(UINT32_MAX - 1024)) /* Evict pages if we see this many consecutive deleted records. */ #define WT_BTREE_DELETE_THRESHOLD WT_THOUSAND /* * Minimum size of the chunks (in percentage of the page size) a page gets split into during * reconciliation. */ #define WT_BTREE_MIN_SPLIT_PCT 50 /* * Normalized position constants for "start" when calculating the page's position. */ #define WT_NPOS_MID 0.5 /* Middle of the current page */ #define WT_NPOS_LEFT -1e-8 /* Leftmost position in the current page or previous page */ #define WT_NPOS_RIGHT (1. + 1e-8) /* Rightmost position in the current page or next page */ /* * Invalid position. This is used to indicate that there is no stored position. The constant -1 * employs the fact that __wt_page_npos returns a number in range 0...1, therefore storing anything * outside of this range can be used as an invalid position. */ #define WT_NPOS_INVALID -1.0 /* Store this as an invalid position */ #define WT_NPOS_IS_INVALID(pos) ((pos) < 0.0) typedef enum __wt_btree_type { BTREE_COL_FIX = 1, /* Fixed-length column store */ BTREE_COL_VAR = 2, /* Variable-length column store */ BTREE_ROW = 3 /* Row-store */ } WT_BTREE_TYPE; typedef enum __wt_btree_sync { WT_BTREE_SYNC_OFF, WT_BTREE_SYNC_WAIT, WT_BTREE_SYNC_RUNNING } WT_BTREE_SYNC; typedef enum { CKSUM_ON = 1, /* On */ CKSUM_OFF = 2, /* Off */ CKSUM_UNCOMPRESSED = 3, /* Uncompressed blocks only */ CKSUM_UNENCRYPTED = 4 /* Unencrypted blocks only */ } WT_BTREE_CHECKSUM; typedef enum { /* Start position for eviction walk */ WT_EVICT_WALK_PREV, WT_EVICT_WALK_NEXT, WT_EVICT_WALK_RAND_NEXT, WT_EVICT_WALK_RAND_PREV } WT_EVICT_WALK_TYPE; /* An invalid btree file ID value. ID 0 is reserved for the metadata file. */ #define WT_BTREE_ID_INVALID UINT32_MAX /* * WT_BTREE -- * A btree handle. */ struct __wt_btree { WT_DATA_HANDLE *dhandle; WT_CKPT *ckpt; /* Checkpoint information */ size_t ckpt_bytes_allocated; /* Checkpoint information array allocation size */ WT_BTREE_TYPE type; /* Type */ const char *key_format; /* Key format */ const char *value_format; /* Value format */ uint8_t bitcnt; /* Fixed-length field size in bits */ WT_COLLATOR *collator; /* Row-store comparator */ int collator_owned; /* The collator needs to be freed */ uint32_t id; /* File ID, for logging */ uint32_t allocsize; /* Allocation size */ wt_shared uint32_t maxintlpage; /* Internal page max size */ uint32_t maxleafpage; /* Leaf page max size */ uint32_t maxleafkey; /* Leaf page max key size */ uint32_t maxleafvalue; /* Leaf page max value size */ uint64_t maxmempage; /* In-memory page max size */ uint32_t maxmempage_image; /* In-memory page image max size */ uint64_t splitmempage; /* In-memory split trigger size */ WT_BTREE_CHECKSUM checksum; /* Checksum configuration */ /* * Reconciliation... */ u_int dictionary; /* Dictionary slots */ bool internal_key_truncate; /* Internal key truncate */ bool prefix_compression; /* Prefix compression */ u_int prefix_compression_min; /* Prefix compression min */ #define WT_SPLIT_DEEPEN_MIN_CHILD_DEF (10 * WT_THOUSAND) u_int split_deepen_min_child; /* Minimum entries to deepen tree */ #define WT_SPLIT_DEEPEN_PER_CHILD_DEF 100 u_int split_deepen_per_child; /* Entries per child when deepened */ int split_pct; /* Split page percent */ WT_COMPRESSOR *compressor; /* Page compressor */ /* * When doing compression, the pre-compression in-memory byte size * is optionally adjusted based on previous compression results. * It's an 8B value because it's updated without a lock. */ bool leafpage_compadjust; /* Run-time compression adjustment */ uint64_t maxleafpage_precomp; /* Leaf page pre-compression size */ bool intlpage_compadjust; /* Run-time compression adjustment */ uint64_t maxintlpage_precomp; /* Internal page pre-compression size */ WT_BUCKET_STORAGE *bstorage; /* Tiered storage source */ WT_KEYED_ENCRYPTOR *kencryptor; /* Page encryptor */ WT_RWLOCK ovfl_lock; /* Overflow lock */ int maximum_depth; /* Maximum tree depth during search */ u_int rec_multiblock_max; /* Maximum blocks written for a page */ uint64_t last_recno; /* Column-store last record number */ WT_REF root; /* Root page reference */ wt_shared bool modified; /* If the tree ever modified */ wt_shared uint8_t original; /* Newly created: bulk-load possible (want a bool but needs atomic cas) */ bool hs_entries; /* Has entries in the history store table */ bool lsm_primary; /* Handle is/was the LSM primary */ WT_BM *bm; /* Block manager reference */ u_int block_header; /* WT_PAGE_HEADER_BYTE_SIZE */ uint64_t write_gen; /* Write generation */ uint64_t base_write_gen; /* Write generation on startup. */ uint64_t run_write_gen; /* Runtime write generation. */ uint64_t rec_max_txn; /* Maximum txn seen (clean trees) */ wt_timestamp_t rec_max_timestamp; wt_shared uint64_t checkpoint_gen; /* Checkpoint generation */ wt_shared WT_SESSION_IMPL *sync_session; /* Syncing session */ wt_shared WT_BTREE_SYNC syncing; /* Sync status */ /* * Helper macros: WT_BTREE_SYNCING indicates if a sync is active (either waiting to start or already * running), so no new operations should start that would conflict with the sync. * WT_SESSION_BTREE_SYNC indicates if the session is performing a sync on its current tree. * WT_SESSION_BTREE_SYNC_SAFE checks whether it is safe to perform an operation that would conflict * with a sync. */ #define WT_BTREE_SYNCING(btree) (__wt_atomic_load_enum(&(btree)->syncing) != WT_BTREE_SYNC_OFF) #define WT_SESSION_BTREE_SYNC(session) \ (__wt_atomic_load_pointer(&S2BT(session)->sync_session) == (session)) #define WT_SESSION_BTREE_SYNC_SAFE(session, btree) \ (__wt_atomic_load_enum(&(btree)->syncing) != WT_BTREE_SYNC_RUNNING || \ __wt_atomic_load_pointer(&(btree)->sync_session) == (session)) wt_shared uint64_t bytes_dirty_intl; /* Bytes in dirty internal pages. */ wt_shared uint64_t bytes_dirty_leaf; /* Bytes in dirty leaf pages. */ wt_shared uint64_t bytes_dirty_total; /* Bytes ever dirtied in cache. */ wt_shared uint64_t bytes_inmem; /* Cache bytes in memory. */ wt_shared uint64_t bytes_internal; /* Bytes in internal pages. */ wt_shared uint64_t bytes_updates; /* Bytes in updates. */ uint64_t max_upd_txn; /* Transaction ID for the latest update on the btree. */ /* * The maximum bytes allowed to be used for the table on disk. This is currently only used for * the history store table. */ uint64_t file_max; /* * We maintain a timer for a clean file to avoid excessive checking of checkpoint information that * incurs a large processing penalty. We avoid that but will periodically incur the cost to clean up * checkpoints that can be deleted. */ #define WT_BTREE_CLEAN_CKPT(session, btree, val) \ do { \ (btree)->clean_ckpt_timer = (val); \ WT_STAT_DSRC_SET((session), btree_clean_checkpoint_timer, (val)); \ } while (0) /* Statistics don't like UINT64_MAX, use INT64_MAX. It's still forever. */ #define WT_BTREE_CLEAN_CKPT_FOREVER INT64_MAX #define WT_BTREE_CLEAN_MINUTES 10 uint64_t clean_ckpt_timer; /* * Track the number of obsolete time window pages that are changed into dirty page * reconciliation by the checkpoint cleanup. */ wt_shared uint32_t checkpoint_cleanup_obsolete_tw_pages; /* * Track the number of obsolete time window pages that are changed into dirty page * reconciliation by the eviction. */ wt_shared uint32_t eviction_obsolete_tw_pages; /* * We flush pages from the tree (in order to make checkpoint faster), without a high-level lock. * To avoid multiple threads flushing at the same time, lock the tree. */ WT_SPINLOCK flush_lock; /* Lock to flush the tree's pages */ uint64_t flush_most_recent_secs; /* Wall clock time for the most recent flush */ uint64_t flush_most_recent_ts; /* Timestamp of the most recent flush */ /* * All of the following fields live at the end of the structure so it's easier to clear everything * but the fields that persist. */ #define WT_BTREE_CLEAR_SIZE (offsetof(WT_BTREE, evict_ref)) /* * Eviction information is maintained in the btree handle, but owned by eviction, not the btree * code. */ WT_REF *evict_ref; /* Eviction thread's location */ uint64_t evict_saved_ref_check; /* Eviction saved thread's location as an ID */ double evict_pos; /* Eviction thread's soft location */ uint32_t linear_walk_restarts; /* next/prev walk restarts */ uint64_t evict_priority; /* Relative priority of cached pages */ uint32_t evict_walk_progress; /* Eviction walk progress */ uint32_t evict_walk_target; /* Eviction walk target */ wt_shared u_int evict_walk_period; /* Skip this many LRU walks */ u_int evict_walk_saved; /* Saved walk skips for checkpoints */ u_int evict_walk_skips; /* Number of walks skipped */ wt_shared int32_t evict_disabled; /* Eviction disabled count */ bool evict_disabled_open; /* Eviction disabled on open */ wt_shared volatile uint32_t evict_busy; /* Count of threads in eviction */ wt_shared volatile uint32_t prefetch_busy; /* Count of threads in prefetch */ WT_EVICT_WALK_TYPE evict_start_type; /* * Flag values up to 0xfff are reserved for WT_DHANDLE_XXX. See comment with dhandle flags for an * explanation. */ /* AUTOMATIC FLAG VALUE GENERATION START 12 */ #define WT_BTREE_ALTER 0x001000u /* Handle is for alter */ #define WT_BTREE_BULK 0x002000u /* Bulk-load handle */ #define WT_BTREE_CLOSED 0x004000u /* Handle closed */ #define WT_BTREE_IGNORE_CACHE 0x008000u /* Cache-resident object */ #define WT_BTREE_IN_MEMORY 0x010000u /* Cache-resident object */ #define WT_BTREE_LOGGED 0x020000u /* Commit-level durability without timestamps */ #define WT_BTREE_NO_CHECKPOINT 0x040000u /* Disable checkpoints */ #define WT_BTREE_OBSOLETE_PAGES 0x080000u /* Handle has obsolete pages */ #define WT_BTREE_READONLY 0x100000u /* Handle is readonly */ #define WT_BTREE_SALVAGE 0x200000u /* Handle is for salvage */ #define WT_BTREE_SKIP_CKPT 0x400000u /* Handle skipped checkpoint */ #define WT_BTREE_VERIFY 0x800000u /* Handle is for verify */ /* AUTOMATIC FLAG VALUE GENERATION STOP 32 */ uint32_t flags; }; /* Flags that make a btree handle special (not for normal use). */ #define WT_BTREE_SPECIAL_FLAGS (WT_BTREE_ALTER | WT_BTREE_BULK | WT_BTREE_SALVAGE | 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 */ bool done; /* Ignore the rest */ };