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/*-------------------------------------------------------------------------
*
* nbtxlog.h
* header file for postgres btree xlog routines
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/access/nbtxlog.h
*
*-------------------------------------------------------------------------
*/
#ifndef NBTXLOG_H
#define NBTXLOG_H
#include "access/xlogreader.h"
#include "lib/stringinfo.h"
#include "storage/off.h"
/*
* XLOG records for btree operations
*
* XLOG allows to store some information in high 4 bits of log
* record xl_info field
*/
#define XLOG_BTREE_INSERT_LEAF 0x00 /* add index tuple without split */
#define XLOG_BTREE_INSERT_UPPER 0x10 /* same, on a non-leaf page */
#define XLOG_BTREE_INSERT_META 0x20 /* same, plus update metapage */
#define XLOG_BTREE_SPLIT_L 0x30 /* add index tuple with split */
#define XLOG_BTREE_SPLIT_R 0x40 /* as above, new item on right */
#define XLOG_BTREE_SPLIT_L_HIGHKEY 0x50 /* as above, include truncated highkey */
#define XLOG_BTREE_SPLIT_R_HIGHKEY 0x60 /* as above, include truncated highkey */
#define XLOG_BTREE_DELETE 0x70 /* delete leaf index tuples for a page */
#define XLOG_BTREE_UNLINK_PAGE 0x80 /* delete a half-dead page */
#define XLOG_BTREE_UNLINK_PAGE_META 0x90 /* same, and update metapage */
#define XLOG_BTREE_NEWROOT 0xA0 /* new root page */
#define XLOG_BTREE_MARK_PAGE_HALFDEAD 0xB0 /* mark a leaf as half-dead */
#define XLOG_BTREE_VACUUM 0xC0 /* delete entries on a page during
* vacuum */
#define XLOG_BTREE_REUSE_PAGE 0xD0 /* old page is about to be reused from
* FSM */
#define XLOG_BTREE_META_CLEANUP 0xE0 /* update cleanup-related data in the
* metapage */
/*
* All that we need to regenerate the meta-data page
*/
typedef struct xl_btree_metadata
{
BlockNumber root;
uint32 level;
BlockNumber fastroot;
uint32 fastlevel;
TransactionId oldest_btpo_xact;
float8 last_cleanup_num_heap_tuples;
} xl_btree_metadata;
/*
* This is what we need to know about simple (without split) insert.
*
* This data record is used for INSERT_LEAF, INSERT_UPPER, INSERT_META.
* Note that INSERT_META implies it's not a leaf page.
*
* Backup Blk 0: original page (data contains the inserted tuple)
* Backup Blk 1: child's left sibling, if INSERT_UPPER or INSERT_META
* Backup Blk 2: xl_btree_metadata, if INSERT_META
*/
typedef struct xl_btree_insert
{
OffsetNumber offnum;
} xl_btree_insert;
#define SizeOfBtreeInsert (offsetof(xl_btree_insert, offnum) + sizeof(OffsetNumber))
/*
* On insert with split, we save all the items going into the right sibling
* so that we can restore it completely from the log record. This way takes
* less xlog space than the normal approach, because if we did it standardly,
* XLogInsert would almost always think the right page is new and store its
* whole page image. The left page, however, is handled in the normal
* incremental-update fashion.
*
* Note: the four XLOG_BTREE_SPLIT xl_info codes all use this data record.
* The _L and _R variants indicate whether the inserted tuple went into the
* left or right split page (and thus, whether the new item is stored or not).
* The _HIGHKEY variants indicate that we've logged explicitly left page high
* key value, otherwise redo should use right page leftmost key as a left page
* high key. _HIGHKEY is specified for internal pages where right page
* leftmost key is suppressed, and for leaf pages of covering indexes where
* high key have non-key attributes truncated.
*
* Backup Blk 0: original page / new left page
*
* The left page's data portion contains the new item, if it's the _L variant.
* (In the _R variants, the new item is one of the right page's tuples.)
* If level > 0, an IndexTuple representing the HIKEY of the left page
* follows. We don't need this on leaf pages, because it's the same as the
* leftmost key in the new right page.
*
* Backup Blk 1: new right page
*
* The right page's data portion contains the right page's tuples in the
* form used by _bt_restore_page.
*
* Backup Blk 2: next block (orig page's rightlink), if any
* Backup Blk 3: child's left sibling, if non-leaf split
*/
typedef struct xl_btree_split
{
uint32 level; /* tree level of page being split */
OffsetNumber firstright; /* first item moved to right page */
OffsetNumber newitemoff; /* new item's offset (useful for _L variant) */
} xl_btree_split;
#define SizeOfBtreeSplit (offsetof(xl_btree_split, newitemoff) + sizeof(OffsetNumber))
/*
* This is what we need to know about delete of individual leaf index tuples.
* The WAL record can represent deletion of any number of index tuples on a
* single index page when *not* executed by VACUUM.
*
* Backup Blk 0: index page
*/
typedef struct xl_btree_delete
{
RelFileNode hnode; /* RelFileNode of the heap the index currently
* points at */
int nitems;
/* TARGET OFFSET NUMBERS FOLLOW AT THE END */
} xl_btree_delete;
#define SizeOfBtreeDelete (offsetof(xl_btree_delete, nitems) + sizeof(int))
/*
* This is what we need to know about page reuse within btree.
*/
typedef struct xl_btree_reuse_page
{
RelFileNode node;
BlockNumber block;
TransactionId latestRemovedXid;
} xl_btree_reuse_page;
#define SizeOfBtreeReusePage (sizeof(xl_btree_reuse_page))
/*
* This is what we need to know about vacuum of individual leaf index tuples.
* The WAL record can represent deletion of any number of index tuples on a
* single index page when executed by VACUUM.
*
* For MVCC scans, lastBlockVacuumed will be set to InvalidBlockNumber.
* For a non-MVCC index scans there is an additional correctness requirement
* for applying these changes during recovery, which is that we must do one
* of these two things for every block in the index:
* * lock the block for cleanup and apply any required changes
* * EnsureBlockUnpinned()
* The purpose of this is to ensure that no index scans started before we
* finish scanning the index are still running by the time we begin to remove
* heap tuples.
*
* Any changes to any one block are registered on just one WAL record. All
* blocks that we need to run EnsureBlockUnpinned() are listed as a block range
* starting from the last block vacuumed through until this one. Individual
* block numbers aren't given.
*
* Note that the *last* WAL record in any vacuum of an index is allowed to
* have a zero length array of offsets. Earlier records must have at least one.
*/
typedef struct xl_btree_vacuum
{
BlockNumber lastBlockVacuumed;
/* TARGET OFFSET NUMBERS FOLLOW */
} xl_btree_vacuum;
#define SizeOfBtreeVacuum (offsetof(xl_btree_vacuum, lastBlockVacuumed) + sizeof(BlockNumber))
/*
* This is what we need to know about marking an empty branch for deletion.
* The target identifies the tuple removed from the parent page (note that we
* remove this tuple's downlink and the *following* tuple's key). Note that
* the leaf page is empty, so we don't need to store its content --- it is
* just reinitialized during recovery using the rest of the fields.
*
* Backup Blk 0: leaf block
* Backup Blk 1: top parent
*/
typedef struct xl_btree_mark_page_halfdead
{
OffsetNumber poffset; /* deleted tuple id in parent page */
/* information needed to recreate the leaf page: */
BlockNumber leafblk; /* leaf block ultimately being deleted */
BlockNumber leftblk; /* leaf block's left sibling, if any */
BlockNumber rightblk; /* leaf block's right sibling */
BlockNumber topparent; /* topmost internal page in the branch */
} xl_btree_mark_page_halfdead;
#define SizeOfBtreeMarkPageHalfDead (offsetof(xl_btree_mark_page_halfdead, topparent) + sizeof(BlockNumber))
/*
* This is what we need to know about deletion of a btree page. Note we do
* not store any content for the deleted page --- it is just rewritten as empty
* during recovery, apart from resetting the btpo.xact.
*
* Backup Blk 0: target block being deleted
* Backup Blk 1: target block's left sibling, if any
* Backup Blk 2: target block's right sibling
* Backup Blk 3: leaf block (if different from target)
* Backup Blk 4: metapage (if rightsib becomes new fast root)
*/
typedef struct xl_btree_unlink_page
{
BlockNumber leftsib; /* target block's left sibling, if any */
BlockNumber rightsib; /* target block's right sibling */
/*
* Information needed to recreate the leaf page, when target is an
* internal page.
*/
BlockNumber leafleftsib;
BlockNumber leafrightsib;
BlockNumber topparent; /* next child down in the branch */
TransactionId btpo_xact; /* value of btpo.xact for use in recovery */
/* xl_btree_metadata FOLLOWS IF XLOG_BTREE_UNLINK_PAGE_META */
} xl_btree_unlink_page;
#define SizeOfBtreeUnlinkPage (offsetof(xl_btree_unlink_page, btpo_xact) + sizeof(TransactionId))
/*
* New root log record. There are zero tuples if this is to establish an
* empty root, or two if it is the result of splitting an old root.
*
* Note that although this implies rewriting the metadata page, we don't need
* an xl_btree_metadata record --- the rootblk and level are sufficient.
*
* Backup Blk 0: new root page (2 tuples as payload, if splitting old root)
* Backup Blk 1: left child (if splitting an old root)
* Backup Blk 2: metapage
*/
typedef struct xl_btree_newroot
{
BlockNumber rootblk; /* location of new root (redundant with blk 0) */
uint32 level; /* its tree level */
} xl_btree_newroot;
#define SizeOfBtreeNewroot (offsetof(xl_btree_newroot, level) + sizeof(uint32))
/*
* prototypes for functions in nbtxlog.c
*/
extern void btree_redo(XLogReaderState *record);
extern void btree_desc(StringInfo buf, XLogReaderState *record);
extern const char *btree_identify(uint8 info);
extern void btree_mask(char *pagedata, BlockNumber blkno);
#endif /* NBXLOG_H */
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