brin_xlog.c

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/*
 * brin_xlog.c
 *      XLog replay routines for BRIN indexes
 *
 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/backend/access/brin/brin_xlog.c
 */
#include "postgres.h"

#include "access/brin_page.h"
#include "access/brin_pageops.h"
#include "access/brin_xlog.h"
#include "access/bufmask.h"
#include "access/xlogutils.h"


/*
 * xlog replay routines
 */
static void
brin_xlog_createidx(XLogReaderState *record)
{
    XLogRecPtr  lsn = record->EndRecPtr;
    xl_brin_createidx *xlrec = (xl_brin_createidx *) XLogRecGetData(record);
    Buffer      buf;
    Page        page;

    /* create the index' metapage */
    buf = XLogInitBufferForRedo(record, 0);
    Assert(BufferIsValid(buf));
    page = (Page) BufferGetPage(buf);
    brin_metapage_init(page, xlrec->pagesPerRange, xlrec->version);
    PageSetLSN(page, lsn);
    MarkBufferDirty(buf);
    UnlockReleaseBuffer(buf);
}

/*
 * Common part of an insert or update. Inserts the new tuple and updates the
 * revmap.
 */
static void
brin_xlog_insert_update(XLogReaderState *record,
                        xl_brin_insert *xlrec)
{
    XLogRecPtr  lsn = record->EndRecPtr;
    Buffer      buffer;
    BlockNumber regpgno;
    Page        page;
    XLogRedoAction action;

    /*
     * If we inserted the first and only tuple on the page, re-initialize the
     * page from scratch.
     */
    if (XLogRecGetInfo(record) & XLOG_BRIN_INIT_PAGE)
    {
        buffer = XLogInitBufferForRedo(record, 0);
        page = BufferGetPage(buffer);
        brin_page_init(page, BRIN_PAGETYPE_REGULAR);
        action = BLK_NEEDS_REDO;
    }
    else
    {
        action = XLogReadBufferForRedo(record, 0, &buffer);
    }

    /* need this page's blkno to store in revmap */
    regpgno = BufferGetBlockNumber(buffer);

    /* insert the index item into the page */
    if (action == BLK_NEEDS_REDO)
    {
        OffsetNumber offnum;
        BrinTuple  *tuple;
        Size        tuplen;

        tuple = (BrinTuple *) XLogRecGetBlockData(record, 0, &tuplen);

        Assert(tuple->bt_blkno == xlrec->heapBlk);

        page = (Page) BufferGetPage(buffer);
        offnum = xlrec->offnum;
        if (PageGetMaxOffsetNumber(page) + 1 < offnum)
            elog(PANIC, "brin_xlog_insert_update: invalid max offset number");

        offnum = PageAddItem(page, (Item) tuple, tuplen, offnum, true, false);
        if (offnum == InvalidOffsetNumber)
            elog(PANIC, "brin_xlog_insert_update: failed to add tuple");

        PageSetLSN(page, lsn);
        MarkBufferDirty(buffer);
    }
    if (BufferIsValid(buffer))
        UnlockReleaseBuffer(buffer);

    /* update the revmap */
    action = XLogReadBufferForRedo(record, 1, &buffer);
    if (action == BLK_NEEDS_REDO)
    {
        ItemPointerData tid;

        ItemPointerSet(&tid, regpgno, xlrec->offnum);
        page = (Page) BufferGetPage(buffer);

        brinSetHeapBlockItemptr(buffer, xlrec->pagesPerRange, xlrec->heapBlk,
                                tid);
        PageSetLSN(page, lsn);
        MarkBufferDirty(buffer);
    }
    if (BufferIsValid(buffer))
        UnlockReleaseBuffer(buffer);

    /* XXX no FSM updates here ... */
}

/*
 * replay a BRIN index insertion
 */
static void
brin_xlog_insert(XLogReaderState *record)
{
    xl_brin_insert *xlrec = (xl_brin_insert *) XLogRecGetData(record);

    brin_xlog_insert_update(record, xlrec);
}

/*
 * replay a BRIN index update
 */
static void
brin_xlog_update(XLogReaderState *record)
{
    XLogRecPtr  lsn = record->EndRecPtr;
    xl_brin_update *xlrec = (xl_brin_update *) XLogRecGetData(record);
    Buffer      buffer;
    XLogRedoAction action;

    /* First remove the old tuple */
    action = XLogReadBufferForRedo(record, 2, &buffer);
    if (action == BLK_NEEDS_REDO)
    {
        Page        page;
        OffsetNumber offnum;

        page = (Page) BufferGetPage(buffer);

        offnum = xlrec->oldOffnum;

        PageIndexTupleDeleteNoCompact(page, offnum);

        PageSetLSN(page, lsn);
        MarkBufferDirty(buffer);
    }

    /* Then insert the new tuple and update revmap, like in an insertion. */
    brin_xlog_insert_update(record, &xlrec->insert);

    if (BufferIsValid(buffer))
        UnlockReleaseBuffer(buffer);
}

/*
 * Update a tuple on a single page.
 */
static void
brin_xlog_samepage_update(XLogReaderState *record)
{
    XLogRecPtr  lsn = record->EndRecPtr;
    xl_brin_samepage_update *xlrec;
    Buffer      buffer;
    XLogRedoAction action;

    xlrec = (xl_brin_samepage_update *) XLogRecGetData(record);
    action = XLogReadBufferForRedo(record, 0, &buffer);
    if (action == BLK_NEEDS_REDO)
    {
        Size        tuplen;
        BrinTuple  *brintuple;
        Page        page;
        OffsetNumber offnum;

        brintuple = (BrinTuple *) XLogRecGetBlockData(record, 0, &tuplen);

        page = (Page) BufferGetPage(buffer);

        offnum = xlrec->offnum;

        if (!PageIndexTupleOverwrite(page, offnum, (Item) brintuple, tuplen))
            elog(PANIC, "brin_xlog_samepage_update: failed to replace tuple");

        PageSetLSN(page, lsn);
        MarkBufferDirty(buffer);
    }
    if (BufferIsValid(buffer))
        UnlockReleaseBuffer(buffer);

    /* XXX no FSM updates here ... */
}

/*
 * Replay a revmap page extension
 */
static void
brin_xlog_revmap_extend(XLogReaderState *record)
{
    XLogRecPtr  lsn = record->EndRecPtr;
    xl_brin_revmap_extend *xlrec;
    Buffer      metabuf;
    Buffer      buf;
    Page        page;
    BlockNumber targetBlk;
    XLogRedoAction action;

    xlrec = (xl_brin_revmap_extend *) XLogRecGetData(record);

    XLogRecGetBlockTag(record, 1, NULL, NULL, &targetBlk);
    Assert(xlrec->targetBlk == targetBlk);

    /* Update the metapage */
    action = XLogReadBufferForRedo(record, 0, &metabuf);
    if (action == BLK_NEEDS_REDO)
    {
        Page        metapg;
        BrinMetaPageData *metadata;

        metapg = BufferGetPage(metabuf);
        metadata = (BrinMetaPageData *) PageGetContents(metapg);

        Assert(metadata->lastRevmapPage == xlrec->targetBlk - 1);
        metadata->lastRevmapPage = xlrec->targetBlk;

        PageSetLSN(metapg, lsn);

        /*
         * 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) metapg)->pd_lower =
            ((char *) metadata + sizeof(BrinMetaPageData)) - (char *) metapg;

        MarkBufferDirty(metabuf);
    }

    /*
     * Re-init the target block as a revmap page.  There's never a full- page
     * image here.
     */

    buf = XLogInitBufferForRedo(record, 1);
    page = (Page) BufferGetPage(buf);
    brin_page_init(page, BRIN_PAGETYPE_REVMAP);

    PageSetLSN(page, lsn);
    MarkBufferDirty(buf);

    UnlockReleaseBuffer(buf);
    if (BufferIsValid(metabuf))
        UnlockReleaseBuffer(metabuf);
}

static void
brin_xlog_desummarize_page(XLogReaderState *record)
{
    XLogRecPtr  lsn = record->EndRecPtr;
    xl_brin_desummarize *xlrec;
    Buffer      buffer;
    XLogRedoAction action;

    xlrec = (xl_brin_desummarize *) XLogRecGetData(record);

    /* Update the revmap */
    action = XLogReadBufferForRedo(record, 0, &buffer);
    if (action == BLK_NEEDS_REDO)
    {
        ItemPointerData iptr;

        ItemPointerSetInvalid(&iptr);
        brinSetHeapBlockItemptr(buffer, xlrec->pagesPerRange, xlrec->heapBlk, iptr);

        PageSetLSN(BufferGetPage(buffer), lsn);
        MarkBufferDirty(buffer);
    }
    if (BufferIsValid(buffer))
        UnlockReleaseBuffer(buffer);

    /* remove the leftover entry from the regular page */
    action = XLogReadBufferForRedo(record, 1, &buffer);
    if (action == BLK_NEEDS_REDO)
    {
        Page        regPg = BufferGetPage(buffer);

        PageIndexTupleDeleteNoCompact(regPg, xlrec->regOffset);

        PageSetLSN(regPg, lsn);
        MarkBufferDirty(buffer);
    }
    if (BufferIsValid(buffer))
        UnlockReleaseBuffer(buffer);
}

void
brin_redo(XLogReaderState *record)
{
    uint8       info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;

    switch (info & XLOG_BRIN_OPMASK)
    {
        case XLOG_BRIN_CREATE_INDEX:
            brin_xlog_createidx(record);
            break;
        case XLOG_BRIN_INSERT:
            brin_xlog_insert(record);
            break;
        case XLOG_BRIN_UPDATE:
            brin_xlog_update(record);
            break;
        case XLOG_BRIN_SAMEPAGE_UPDATE:
            brin_xlog_samepage_update(record);
            break;
        case XLOG_BRIN_REVMAP_EXTEND:
            brin_xlog_revmap_extend(record);
            break;
        case XLOG_BRIN_DESUMMARIZE:
            brin_xlog_desummarize_page(record);
            break;
        default:
            elog(PANIC, "brin_redo: unknown op code %u", info);
    }
}

/*
 * Mask a BRIN page before doing consistency checks.
 */
void
brin_mask(char *pagedata, BlockNumber blkno)
{
    Page        page = (Page) pagedata;
    PageHeader  pagehdr = (PageHeader) page;

    mask_page_lsn_and_checksum(page);

    mask_page_hint_bits(page);

    /*
     * Regular brin pages contain unused space which needs to be masked.
     * Similarly for meta pages, but mask it only if pd_lower appears to have
     * been set correctly.
     */
    if (BRIN_IS_REGULAR_PAGE(page) ||
        (BRIN_IS_META_PAGE(page) && pagehdr->pd_lower > SizeOfPageHeaderData))
    {
        mask_unused_space(page);
    }
}