pgstattuple.c File Reference

#include "postgres.h"
#include "access/gist_private.h"
#include "access/hash.h"
#include "access/heapam.h"
#include "access/nbtree.h"
#include "access/relscan.h"
#include "access/tableam.h"
#include "catalog/namespace.h"
#include "catalog/pg_am_d.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "utils/builtins.h"
#include "utils/varlena.h"

Include dependency graph for pgstattuple.c:

Go to the source code of this file.

Data Structures
struct	pgstattuple_type

Macros
#define	NCOLUMNS   9
#define	NCHARS   314

Typedefs
typedef struct pgstattuple_type	pgstattuple_type
typedef void(*	pgstat_page) (pgstattuple_type *, Relation, BlockNumber, BufferAccessStrategy)

Functions
	PG_FUNCTION_INFO_V1 (pgstattuple)
	PG_FUNCTION_INFO_V1 (pgstattuple_v1_5)
	PG_FUNCTION_INFO_V1 (pgstattuplebyid)
	PG_FUNCTION_INFO_V1 (pgstattuplebyid_v1_5)
static Datum	build_pgstattuple_type (pgstattuple_type *stat, FunctionCallInfo fcinfo)
static Datum	pgstat_relation (Relation rel, FunctionCallInfo fcinfo)
static Datum	pgstat_heap (Relation rel, FunctionCallInfo fcinfo)
static void	pgstat_btree_page (pgstattuple_type *stat, Relation rel, BlockNumber blkno, BufferAccessStrategy bstrategy)
static void	pgstat_hash_page (pgstattuple_type *stat, Relation rel, BlockNumber blkno, BufferAccessStrategy bstrategy)
static void	pgstat_gist_page (pgstattuple_type *stat, Relation rel, BlockNumber blkno, BufferAccessStrategy bstrategy)
static Datum	pgstat_index (Relation rel, BlockNumber start, pgstat_page pagefn, FunctionCallInfo fcinfo)
static void	pgstat_index_page (pgstattuple_type *stat, Page page, OffsetNumber minoff, OffsetNumber maxoff)
Datum	pgstattuple (PG_FUNCTION_ARGS)
Datum	pgstattuple_v1_5 (PG_FUNCTION_ARGS)
Datum	pgstattuplebyid (PG_FUNCTION_ARGS)
Datum	pgstattuplebyid_v1_5 (PG_FUNCTION_ARGS)

Variables
	PG_MODULE_MAGIC

Macro Definition Documentation

NCHARS

#define NCHARS   314

NCOLUMNS

#define NCOLUMNS   9

Typedef Documentation

pgstat_page

typedef void(* pgstat_page) (pgstattuple_type *, Relation, BlockNumber, BufferAccessStrategy)

Definition at line 65 of file pgstattuple.c.

pgstattuple_type

typedef struct pgstattuple_type pgstattuple_type

Function Documentation

build_pgstattuple_type()

static Datum build_pgstattuple_type ( pgstattuple_type *  stat, FunctionCallInfo  fcinfo  )

static

Definition at line 90 of file pgstattuple.c.

{
#define NCOLUMNS    9
#define NCHARS      314
 
    HeapTuple   tuple;
    char       *values[NCOLUMNS];
    char        values_buf[NCOLUMNS][NCHARS];
    int         i;
    double      tuple_percent;
    double      dead_tuple_percent;
    double      free_percent;   /* free/reusable space in % */
    TupleDesc   tupdesc;
    AttInMetadata *attinmeta;
 
    /* Build a tuple descriptor for our result type */
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
    /*
     * Generate attribute metadata needed later to produce tuples from raw C
     * strings
     */
    attinmeta = TupleDescGetAttInMetadata(tupdesc);
 
    if (stat->table_len == 0)
    {
        tuple_percent = 0.0;
        dead_tuple_percent = 0.0;
        free_percent = 0.0;
    }
    else
    {
        tuple_percent = 100.0 * stat->tuple_len / stat->table_len;
        dead_tuple_percent = 100.0 * stat->dead_tuple_len / stat->table_len;
        free_percent = 100.0 * stat->free_space / stat->table_len;
    }
 
    /*
     * Prepare a values array for constructing the tuple. This should be an
     * array of C strings which will be processed later by the appropriate
     * "in" functions.
     */
    for (i = 0; i < NCOLUMNS; i++)
        values[i] = values_buf[i];
    i = 0;
    snprintf(values[i++], NCHARS, INT64_FORMAT, stat->table_len);
    snprintf(values[i++], NCHARS, INT64_FORMAT, stat->tuple_count);
    snprintf(values[i++], NCHARS, INT64_FORMAT, stat->tuple_len);
    snprintf(values[i++], NCHARS, "%.2f", tuple_percent);
    snprintf(values[i++], NCHARS, INT64_FORMAT, stat->dead_tuple_count);
    snprintf(values[i++], NCHARS, INT64_FORMAT, stat->dead_tuple_len);
    snprintf(values[i++], NCHARS, "%.2f", dead_tuple_percent);
    snprintf(values[i++], NCHARS, INT64_FORMAT, stat->free_space);
    snprintf(values[i++], NCHARS, "%.2f", free_percent);
 
    /* build a tuple */
    tuple = BuildTupleFromCStrings(attinmeta, values);
 
    /* make the tuple into a datum */
    return HeapTupleGetDatum(tuple);
}

References BuildTupleFromCStrings(), elog, ERROR, get_call_result_type(), HeapTupleGetDatum, i, INT64_FORMAT, NCHARS, NCOLUMNS, snprintf, TupleDescGetAttInMetadata(), TYPEFUNC_COMPOSITE, and values.

Referenced by pgstat_heap(), and pgstat_index().

PG_FUNCTION_INFO_V1() [1/4]

PG_FUNCTION_INFO_V1

(

pgstattuple

)

PG_FUNCTION_INFO_V1() [2/4]

PG_FUNCTION_INFO_V1

(

pgstattuple_v1_5

)

PG_FUNCTION_INFO_V1() [3/4]

PG_FUNCTION_INFO_V1

(

pgstattuplebyid

)

PG_FUNCTION_INFO_V1() [4/4]

PG_FUNCTION_INFO_V1

(

pgstattuplebyid_v1_5

)

pgstat_btree_page()

static void pgstat_btree_page ( pgstattuple_type *  stat, Relation  rel, BlockNumber  blkno, BufferAccessStrategy  bstrategy  )

static

Definition at line 398 of file pgstattuple.c.

{
    Buffer      buf;
    Page        page;
 
    buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy);
    LockBuffer(buf, BT_READ);
    page = BufferGetPage(buf);
 
    /* Page is valid, see what to do with it */
    if (PageIsNew(page))
    {
        /* fully empty page */
        stat->free_space += BLCKSZ;
    }
    else
    {
        BTPageOpaque opaque;
 
        opaque = BTPageGetOpaque(page);
        if (P_IGNORE(opaque))
        {
            /* deleted or half-dead page */
            stat->free_space += BLCKSZ;
        }
        else if (P_ISLEAF(opaque))
        {
            pgstat_index_page(stat, page, P_FIRSTDATAKEY(opaque),
                              PageGetMaxOffsetNumber(page));
        }
        else
        {
            /* internal page */
        }
    }
 
    _bt_relbuf(rel, buf);
}

References _bt_relbuf(), BT_READ, BTPageGetOpaque, buf, BufferGetPage, LockBuffer(), MAIN_FORKNUM, P_FIRSTDATAKEY, P_IGNORE, P_ISLEAF, PageGetMaxOffsetNumber, PageIsNew, pgstat_index_page(), RBM_NORMAL, and ReadBufferExtended().

Referenced by pgstat_relation().

pgstat_gist_page()

static void pgstat_gist_page ( pgstattuple_type *  stat, Relation  rel, BlockNumber  blkno, BufferAccessStrategy  bstrategy  )

static

Definition at line 484 of file pgstattuple.c.

{
    Buffer      buf;
    Page        page;
 
    buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy);
    LockBuffer(buf, GIST_SHARE);
    gistcheckpage(rel, buf);
    page = BufferGetPage(buf);
 
    if (GistPageIsLeaf(page))
    {
        pgstat_index_page(stat, page, FirstOffsetNumber,
                          PageGetMaxOffsetNumber(page));
    }
    else
    {
        /* root or node */
    }
 
    UnlockReleaseBuffer(buf);
}

References buf, BufferGetPage, FirstOffsetNumber, GIST_SHARE, gistcheckpage(), GistPageIsLeaf, LockBuffer(), MAIN_FORKNUM, PageGetMaxOffsetNumber, pgstat_index_page(), RBM_NORMAL, ReadBufferExtended(), and UnlockReleaseBuffer().

Referenced by pgstat_relation().

pgstat_hash_page()

static void pgstat_hash_page ( pgstattuple_type *  stat, Relation  rel, BlockNumber  blkno, BufferAccessStrategy  bstrategy  )

static

Definition at line 442 of file pgstattuple.c.

{
    Buffer      buf;
    Page        page;
 
    buf = _hash_getbuf_with_strategy(rel, blkno, HASH_READ, 0, bstrategy);
    page = BufferGetPage(buf);
 
    if (PageGetSpecialSize(page) == MAXALIGN(sizeof(HashPageOpaqueData)))
    {
        HashPageOpaque opaque;
 
        opaque = HashPageGetOpaque(page);
        switch (opaque->hasho_flag & LH_PAGE_TYPE)
        {
            case LH_UNUSED_PAGE:
                stat->free_space += BLCKSZ;
                break;
            case LH_BUCKET_PAGE:
            case LH_OVERFLOW_PAGE:
                pgstat_index_page(stat, page, FirstOffsetNumber,
                                  PageGetMaxOffsetNumber(page));
                break;
            case LH_BITMAP_PAGE:
            case LH_META_PAGE:
            default:
                break;
        }
    }
    else
    {
        /* maybe corrupted */
    }
 
    _hash_relbuf(rel, buf);
}

References _hash_getbuf_with_strategy(), _hash_relbuf(), buf, BufferGetPage, FirstOffsetNumber, HASH_READ, HashPageOpaqueData::hasho_flag, HashPageGetOpaque, LH_BITMAP_PAGE, LH_BUCKET_PAGE, LH_META_PAGE, LH_OVERFLOW_PAGE, LH_PAGE_TYPE, LH_UNUSED_PAGE, MAXALIGN, PageGetMaxOffsetNumber, PageGetSpecialSize, and pgstat_index_page().

Referenced by pgstat_relation().

pgstat_heap()

static Datum pgstat_heap ( Relation  rel, FunctionCallInfo  fcinfo  )

static

Definition at line 307 of file pgstattuple.c.

{
    TableScanDesc scan;
    HeapScanDesc hscan;
    HeapTuple   tuple;
    BlockNumber nblocks;
    BlockNumber block = 0;      /* next block to count free space in */
    BlockNumber tupblock;
    Buffer      buffer;
    pgstattuple_type stat = {0};
    SnapshotData SnapshotDirty;
 
    if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("only heap AM is supported")));
 
    /* Disable syncscan because we assume we scan from block zero upwards */
    scan = table_beginscan_strat(rel, SnapshotAny, 0, NULL, true, false);
    hscan = (HeapScanDesc) scan;
 
    InitDirtySnapshot(SnapshotDirty);
 
    nblocks = hscan->rs_nblocks;    /* # blocks to be scanned */
 
    /* scan the relation */
    while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
    {
        CHECK_FOR_INTERRUPTS();
 
        /* must hold a buffer lock to call HeapTupleSatisfiesVisibility */
        LockBuffer(hscan->rs_cbuf, BUFFER_LOCK_SHARE);
 
        if (HeapTupleSatisfiesVisibility(tuple, &SnapshotDirty, hscan->rs_cbuf))
        {
            stat.tuple_len += tuple->t_len;
            stat.tuple_count++;
        }
        else
        {
            stat.dead_tuple_len += tuple->t_len;
            stat.dead_tuple_count++;
        }
 
        LockBuffer(hscan->rs_cbuf, BUFFER_LOCK_UNLOCK);
 
        /*
         * To avoid physically reading the table twice, try to do the
         * free-space scan in parallel with the heap scan.  However,
         * heap_getnext may find no tuples on a given page, so we cannot
         * simply examine the pages returned by the heap scan.
         */
        tupblock = ItemPointerGetBlockNumber(&tuple->t_self);
 
        while (block <= tupblock)
        {
            CHECK_FOR_INTERRUPTS();
 
            buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block,
                                        RBM_NORMAL, hscan->rs_strategy);
            LockBuffer(buffer, BUFFER_LOCK_SHARE);
            stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
            UnlockReleaseBuffer(buffer);
            block++;
        }
    }
 
    while (block < nblocks)
    {
        CHECK_FOR_INTERRUPTS();
 
        buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block,
                                    RBM_NORMAL, hscan->rs_strategy);
        LockBuffer(buffer, BUFFER_LOCK_SHARE);
        stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
        UnlockReleaseBuffer(buffer);
        block++;
    }
 
    table_endscan(scan);
    relation_close(rel, AccessShareLock);
 
    stat.table_len = (uint64) nblocks * BLCKSZ;
 
    return build_pgstattuple_type(&stat, fcinfo);
}

References AccessShareLock, BUFFER_LOCK_SHARE, BUFFER_LOCK_UNLOCK, BufferGetPage, build_pgstattuple_type(), CHECK_FOR_INTERRUPTS, ereport, errcode(), errmsg(), ERROR, ForwardScanDirection, heap_getnext(), HeapTupleSatisfiesVisibility(), InitDirtySnapshot, ItemPointerGetBlockNumber, LockBuffer(), MAIN_FORKNUM, PageGetHeapFreeSpace(), RBM_NORMAL, RelationData::rd_rel, ReadBufferExtended(), relation_close(), HeapScanDescData::rs_cbuf, HeapScanDescData::rs_nblocks, HeapScanDescData::rs_strategy, SnapshotAny, HeapTupleData::t_len, HeapTupleData::t_self, table_beginscan_strat(), table_endscan(), and UnlockReleaseBuffer().

Referenced by pgstat_relation().

pgstat_index()

static Datum pgstat_index ( Relation  rel, BlockNumber  start, pgstat_page  pagefn, FunctionCallInfo  fcinfo  )

static

Definition at line 512 of file pgstattuple.c.

{
    BlockNumber nblocks;
    BlockNumber blkno;
    BufferAccessStrategy bstrategy;
    pgstattuple_type stat = {0};
 
    /* prepare access strategy for this index */
    bstrategy = GetAccessStrategy(BAS_BULKREAD);
 
    blkno = start;
    for (;;)
    {
        /* Get the current relation length */
        LockRelationForExtension(rel, ExclusiveLock);
        nblocks = RelationGetNumberOfBlocks(rel);
        UnlockRelationForExtension(rel, ExclusiveLock);
 
        /* Quit if we've scanned the whole relation */
        if (blkno >= nblocks)
        {
            stat.table_len = (uint64) nblocks * BLCKSZ;
 
            break;
        }
 
        for (; blkno < nblocks; blkno++)
        {
            CHECK_FOR_INTERRUPTS();
 
            pagefn(&stat, rel, blkno, bstrategy);
        }
    }
 
    relation_close(rel, AccessShareLock);
 
    return build_pgstattuple_type(&stat, fcinfo);
}

References AccessShareLock, BAS_BULKREAD, build_pgstattuple_type(), CHECK_FOR_INTERRUPTS, ExclusiveLock, GetAccessStrategy(), LockRelationForExtension(), relation_close(), RelationGetNumberOfBlocks, and UnlockRelationForExtension().

Referenced by pgstat_relation().

pgstat_index_page()

static void pgstat_index_page ( pgstattuple_type *  stat, Page  page, OffsetNumber  minoff, OffsetNumber  maxoff  )

static

Definition at line 556 of file pgstattuple.c.

{
    OffsetNumber i;
 
    stat->free_space += PageGetFreeSpace(page);
 
    for (i = minoff; i <= maxoff; i = OffsetNumberNext(i))
    {
        ItemId      itemid = PageGetItemId(page, i);
 
        if (ItemIdIsDead(itemid))
        {
            stat->dead_tuple_count++;
            stat->dead_tuple_len += ItemIdGetLength(itemid);
        }
        else
        {
            stat->tuple_count++;
            stat->tuple_len += ItemIdGetLength(itemid);
        }
    }
}

References i, ItemIdGetLength, ItemIdIsDead, OffsetNumberNext, PageGetFreeSpace(), and PageGetItemId.

Referenced by pgstat_btree_page(), pgstat_gist_page(), and pgstat_hash_page().

pgstat_relation()

static Datum pgstat_relation ( Relation  rel, FunctionCallInfo  fcinfo  )

static

Definition at line 241 of file pgstattuple.c.

{
    const char *err;
 
    /*
     * Reject attempts to read non-local temporary relations; we would be
     * likely to get wrong data since we have no visibility into the owning
     * session's local buffers.
     */
    if (RELATION_IS_OTHER_TEMP(rel))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("cannot access temporary tables of other sessions")));
 
    if (RELKIND_HAS_TABLE_AM(rel->rd_rel->relkind) ||
        rel->rd_rel->relkind == RELKIND_SEQUENCE)
    {
        return pgstat_heap(rel, fcinfo);
    }
    else if (rel->rd_rel->relkind == RELKIND_INDEX)
    {
        switch (rel->rd_rel->relam)
        {
            case BTREE_AM_OID:
                return pgstat_index(rel, BTREE_METAPAGE + 1,
                                    pgstat_btree_page, fcinfo);
            case HASH_AM_OID:
                return pgstat_index(rel, HASH_METAPAGE + 1,
                                    pgstat_hash_page, fcinfo);
            case GIST_AM_OID:
                return pgstat_index(rel, GIST_ROOT_BLKNO + 1,
                                    pgstat_gist_page, fcinfo);
            case GIN_AM_OID:
                err = "gin index";
                break;
            case SPGIST_AM_OID:
                err = "spgist index";
                break;
            case BRIN_AM_OID:
                err = "brin index";
                break;
            default:
                err = "unknown index";
                break;
        }
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("index \"%s\" (%s) is not supported",
                        RelationGetRelationName(rel), err)));
    }
    else
    {
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("cannot get tuple-level statistics for relation \"%s\"",
                        RelationGetRelationName(rel)),
                 errdetail_relkind_not_supported(rel->rd_rel->relkind)));
    }
 
    return 0;                   /* should not happen */
}

References BTREE_METAPAGE, ereport, errcode(), errdetail_relkind_not_supported(), errmsg(), ERROR, GIST_ROOT_BLKNO, HASH_METAPAGE, pgstat_btree_page(), pgstat_gist_page(), pgstat_hash_page(), pgstat_heap(), pgstat_index(), RelationData::rd_rel, RELATION_IS_OTHER_TEMP, and RelationGetRelationName.

Referenced by pgstattuple(), pgstattuple_v1_5(), pgstattuplebyid(), and pgstattuplebyid_v1_5().

pgstattuple()

Datum pgstattuple

(

PG_FUNCTION_ARGS

)

Definition at line 167 of file pgstattuple.c.

{
    text       *relname = PG_GETARG_TEXT_PP(0);
    RangeVar   *relrv;
    Relation    rel;
 
    if (!superuser())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be superuser to use pgstattuple functions")));
 
    /* open relation */
    relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
    rel = relation_openrv(relrv, AccessShareLock);
 
    PG_RETURN_DATUM(pgstat_relation(rel, fcinfo));
}

References AccessShareLock, ereport, errcode(), errmsg(), ERROR, makeRangeVarFromNameList(), PG_GETARG_TEXT_PP, PG_RETURN_DATUM, pgstat_relation(), relation_openrv(), relname, superuser(), and textToQualifiedNameList().

pgstattuple_v1_5()

Datum pgstattuple_v1_5

(

PG_FUNCTION_ARGS

)

Definition at line 193 of file pgstattuple.c.

{
    text       *relname = PG_GETARG_TEXT_PP(0);
    RangeVar   *relrv;
    Relation    rel;
 
    /* open relation */
    relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
    rel = relation_openrv(relrv, AccessShareLock);
 
    PG_RETURN_DATUM(pgstat_relation(rel, fcinfo));
}

References AccessShareLock, makeRangeVarFromNameList(), PG_GETARG_TEXT_PP, PG_RETURN_DATUM, pgstat_relation(), relation_openrv(), relname, and textToQualifiedNameList().

pgstattuplebyid()

Datum pgstattuplebyid

(

PG_FUNCTION_ARGS

)

Definition at line 208 of file pgstattuple.c.

{
    Oid         relid = PG_GETARG_OID(0);
    Relation    rel;
 
    if (!superuser())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be superuser to use pgstattuple functions")));
 
    /* open relation */
    rel = relation_open(relid, AccessShareLock);
 
    PG_RETURN_DATUM(pgstat_relation(rel, fcinfo));
}

References AccessShareLock, ereport, errcode(), errmsg(), ERROR, PG_GETARG_OID, PG_RETURN_DATUM, pgstat_relation(), relation_open(), and superuser().

pgstattuplebyid_v1_5()

Datum pgstattuplebyid_v1_5

(

PG_FUNCTION_ARGS

)

Definition at line 226 of file pgstattuple.c.

{
    Oid         relid = PG_GETARG_OID(0);
    Relation    rel;
 
    /* open relation */
    rel = relation_open(relid, AccessShareLock);
 
    PG_RETURN_DATUM(pgstat_relation(rel, fcinfo));
}

References AccessShareLock, PG_GETARG_OID, PG_RETURN_DATUM, pgstat_relation(), and relation_open().

Variable Documentation

PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 42 of file pgstattuple.c.