spginsert.c

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/*-------------------------------------------------------------------------
 *
 * spginsert.c
 *    Externally visible index creation/insertion routines
 *
 * All the actual insertion logic is in spgdoinsert.c.
 *
 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *          src/backend/access/spgist/spginsert.c
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include "access/genam.h"
#include "access/spgist_private.h"
#include "access/spgxlog.h"
#include "access/tableam.h"
#include "access/xlog.h"
#include "access/xloginsert.h"
#include "catalog/index.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
#include "storage/smgr.h"
#include "utils/memutils.h"
#include "utils/rel.h"


typedef struct
{
    SpGistState spgstate;       /* SPGiST's working state */
    int64       indtuples;      /* total number of tuples indexed */
    MemoryContext tmpCtx;       /* per-tuple temporary context */
} SpGistBuildState;


/* Callback to process one heap tuple during table_index_build_scan */
static void
spgistBuildCallback(Relation index, ItemPointer tid, Datum *values,
                    bool *isnull, bool tupleIsAlive, void *state)
{
    SpGistBuildState *buildstate = (SpGistBuildState *) state;
    MemoryContext oldCtx;

    /* Work in temp context, and reset it after each tuple */
    oldCtx = MemoryContextSwitchTo(buildstate->tmpCtx);

    /*
     * Even though no concurrent insertions can be happening, we still might
     * get a buffer-locking failure due to bgwriter or checkpointer taking a
     * lock on some buffer.  So we need to be willing to retry.  We can flush
     * any temp data when retrying.
     */
    while (!spgdoinsert(index, &buildstate->spgstate, tid,
                        *values, *isnull))
    {
        MemoryContextReset(buildstate->tmpCtx);
    }

    /* Update total tuple count */
    buildstate->indtuples += 1;

    MemoryContextSwitchTo(oldCtx);
    MemoryContextReset(buildstate->tmpCtx);
}

/*
 * Build an SP-GiST index.
 */
IndexBuildResult *
spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
{
    IndexBuildResult *result;
    double      reltuples;
    SpGistBuildState buildstate;
    Buffer      metabuffer,
                rootbuffer,
                nullbuffer;

    if (RelationGetNumberOfBlocks(index) != 0)
        elog(ERROR, "index \"%s\" already contains data",
             RelationGetRelationName(index));

    /*
     * Initialize the meta page and root pages
     */
    metabuffer = SpGistNewBuffer(index);
    rootbuffer = SpGistNewBuffer(index);
    nullbuffer = SpGistNewBuffer(index);

    Assert(BufferGetBlockNumber(metabuffer) == SPGIST_METAPAGE_BLKNO);
    Assert(BufferGetBlockNumber(rootbuffer) == SPGIST_ROOT_BLKNO);
    Assert(BufferGetBlockNumber(nullbuffer) == SPGIST_NULL_BLKNO);

    START_CRIT_SECTION();

    SpGistInitMetapage(BufferGetPage(metabuffer));
    MarkBufferDirty(metabuffer);
    SpGistInitBuffer(rootbuffer, SPGIST_LEAF);
    MarkBufferDirty(rootbuffer);
    SpGistInitBuffer(nullbuffer, SPGIST_LEAF | SPGIST_NULLS);
    MarkBufferDirty(nullbuffer);


    END_CRIT_SECTION();

    UnlockReleaseBuffer(metabuffer);
    UnlockReleaseBuffer(rootbuffer);
    UnlockReleaseBuffer(nullbuffer);

    /*
     * Now insert all the heap data into the index
     */
    initSpGistState(&buildstate.spgstate, index);
    buildstate.spgstate.isBuild = true;
    buildstate.indtuples = 0;

    buildstate.tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
                                              "SP-GiST build temporary context",
                                              ALLOCSET_DEFAULT_SIZES);

    reltuples = table_index_build_scan(heap, index, indexInfo, true, true,
                                       spgistBuildCallback, (void *) &buildstate,
                                       NULL);

    MemoryContextDelete(buildstate.tmpCtx);

    SpGistUpdateMetaPage(index);

    /*
     * We didn't write WAL records as we built the index, so if WAL-logging is
     * required, write all pages to the WAL now.
     */
    if (RelationNeedsWAL(index))
    {
        log_newpage_range(index, MAIN_FORKNUM,
                          0, RelationGetNumberOfBlocks(index),
                          true);
    }

    result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
    result->heap_tuples = reltuples;
    result->index_tuples = buildstate.indtuples;

    return result;
}

/*
 * Build an empty SPGiST index in the initialization fork
 */
void
spgbuildempty(Relation index)
{
    Page        page;

    /* Construct metapage. */
    page = (Page) palloc(BLCKSZ);
    SpGistInitMetapage(page);

    /*
     * Write the page and log it unconditionally.  This is important
     * particularly for indexes created on tablespaces and databases whose
     * creation happened after the last redo pointer as recovery removes any
     * of their existing content when the corresponding create records are
     * replayed.
     */
    PageSetChecksumInplace(page, SPGIST_METAPAGE_BLKNO);
    smgrwrite(index->rd_smgr, INIT_FORKNUM, SPGIST_METAPAGE_BLKNO,
              (char *) page, true);
    log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
                SPGIST_METAPAGE_BLKNO, page, true);

    /* Likewise for the root page. */
    SpGistInitPage(page, SPGIST_LEAF);

    PageSetChecksumInplace(page, SPGIST_ROOT_BLKNO);
    smgrwrite(index->rd_smgr, INIT_FORKNUM, SPGIST_ROOT_BLKNO,
              (char *) page, true);
    log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
                SPGIST_ROOT_BLKNO, page, true);

    /* Likewise for the null-tuples root page. */
    SpGistInitPage(page, SPGIST_LEAF | SPGIST_NULLS);

    PageSetChecksumInplace(page, SPGIST_NULL_BLKNO);
    smgrwrite(index->rd_smgr, INIT_FORKNUM, SPGIST_NULL_BLKNO,
              (char *) page, true);
    log_newpage(&index->rd_smgr->smgr_rnode.node, INIT_FORKNUM,
                SPGIST_NULL_BLKNO, page, true);

    /*
     * An immediate sync is required even if we xlog'd the pages, because the
     * writes did not go through shared buffers and therefore a concurrent
     * checkpoint may have moved the redo pointer past our xlog record.
     */
    smgrimmedsync(index->rd_smgr, INIT_FORKNUM);
}

/*
 * Insert one new tuple into an SPGiST index.
 */
bool
spginsert(Relation index, Datum *values, bool *isnull,
          ItemPointer ht_ctid, Relation heapRel,
          IndexUniqueCheck checkUnique,
          IndexInfo *indexInfo)
{
    SpGistState spgstate;
    MemoryContext oldCtx;
    MemoryContext insertCtx;

    insertCtx = AllocSetContextCreate(CurrentMemoryContext,
                                      "SP-GiST insert temporary context",
                                      ALLOCSET_DEFAULT_SIZES);
    oldCtx = MemoryContextSwitchTo(insertCtx);

    initSpGistState(&spgstate, index);

    /*
     * We might have to repeat spgdoinsert() multiple times, if conflicts
     * occur with concurrent insertions.  If so, reset the insertCtx each time
     * to avoid cumulative memory consumption.  That means we also have to
     * redo initSpGistState(), but it's cheap enough not to matter.
     */
    while (!spgdoinsert(index, &spgstate, ht_ctid, *values, *isnull))
    {
        MemoryContextReset(insertCtx);
        initSpGistState(&spgstate, index);
    }

    SpGistUpdateMetaPage(index);

    MemoryContextSwitchTo(oldCtx);
    MemoryContextDelete(insertCtx);

    /* return false since we've not done any unique check */
    return false;
}