gistxlog.h

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/*-------------------------------------------------------------------------
 *
 * gistxlog.h
 *    gist xlog routines
 *
 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/access/gistxlog.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef GIST_XLOG_H
#define GIST_XLOG_H

#include "access/gist.h"
#include "access/xlogreader.h"
#include "lib/stringinfo.h"

#define XLOG_GIST_PAGE_UPDATE       0x00
#define XLOG_GIST_DELETE            0x10    /* delete leaf index tuples for a
                                             * page */
#define XLOG_GIST_PAGE_REUSE        0x20    /* old page is about to be reused
                                             * from FSM */
#define XLOG_GIST_PAGE_SPLIT        0x30
 /* #define XLOG_GIST_INSERT_COMPLETE    0x40 */    /* not used anymore */
 /* #define XLOG_GIST_CREATE_INDEX       0x50 */    /* not used anymore */
#define XLOG_GIST_PAGE_DELETE       0x60
#define XLOG_GIST_ASSIGN_LSN        0x70    /* nop, assign new LSN */

/*
 * Backup Blk 0: updated page.
 * Backup Blk 1: If this operation completes a page split, by inserting a
 *               downlink for the split page, the left half of the split
 */
typedef struct gistxlogPageUpdate
{
    /* number of deleted offsets */
    uint16      ntodelete;
    uint16      ntoinsert;

    /*
     * In payload of blk 0 : 1. todelete OffsetNumbers 2. tuples to insert
     */
} gistxlogPageUpdate;

/*
 * Backup Blk 0: Leaf page, whose index tuples are deleted.
 */
typedef struct gistxlogDelete
{
    TransactionId latestRemovedXid;
    uint16      ntodelete;      /* number of deleted offsets */

    /*
     * In payload of blk 0 : todelete OffsetNumbers
     */
} gistxlogDelete;

#define SizeOfGistxlogDelete    (offsetof(gistxlogDelete, ntodelete) + sizeof(uint16))

/*
 * Backup Blk 0: If this operation completes a page split, by inserting a
 *               downlink for the split page, the left half of the split
 * Backup Blk 1 - npage: split pages (1 is the original page)
 */
typedef struct gistxlogPageSplit
{
    BlockNumber origrlink;      /* rightlink of the page before split */
    GistNSN     orignsn;        /* NSN of the page before split */
    bool        origleaf;       /* was splitted page a leaf page? */

    uint16      npage;          /* # of pages in the split */
    bool        markfollowright;    /* set F_FOLLOW_RIGHT flags */

    /*
     * follow: 1. gistxlogPage and array of IndexTupleData per page
     */
} gistxlogPageSplit;

/*
 * Backup Blk 0: page that was deleted.
 * Backup Blk 1: parent page, containing the downlink to the deleted page.
 */
typedef struct gistxlogPageDelete
{
    FullTransactionId deleteXid;    /* last Xid which could see page in scan */
    OffsetNumber downlinkOffset;    /* Offset of downlink referencing this
                                     * page */
} gistxlogPageDelete;

#define SizeOfGistxlogPageDelete    (offsetof(gistxlogPageDelete, downlinkOffset) + sizeof(OffsetNumber))


/*
 * This is what we need to know about page reuse, for hot standby.
 */
typedef struct gistxlogPageReuse
{
    RelFileNode node;
    BlockNumber block;
    FullTransactionId latestRemovedFullXid;
} gistxlogPageReuse;

#define SizeOfGistxlogPageReuse (offsetof(gistxlogPageReuse, latestRemovedFullXid) + sizeof(FullTransactionId))

extern void gist_redo(XLogReaderState *record);
extern void gist_desc(StringInfo buf, XLogReaderState *record);
extern const char *gist_identify(uint8 info);
extern void gist_xlog_startup(void);
extern void gist_xlog_cleanup(void);
extern void gist_mask(char *pagedata, BlockNumber blkno);

#endif