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-rw-r--r--contrib/pgstattuple/pgstattuple.c585
-rw-r--r--contrib/pgstattuple/pgstattuple.control5
2 files changed, 590 insertions, 0 deletions
diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c
new file mode 100644
index 0000000..3bd8b96
--- /dev/null
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -0,0 +1,585 @@
+/*
+ * contrib/pgstattuple/pgstattuple.c
+ *
+ * Copyright (c) 2001,2002 Tatsuo Ishii
+ *
+ * Permission to use, copy, modify, and distribute this software and
+ * its documentation for any purpose, without fee, and without a
+ * written agreement is hereby granted, provided that the above
+ * copyright notice and this paragraph and the following two
+ * paragraphs appear in all copies.
+ *
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
+ * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
+ * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
+ * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
+ * IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
+ * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ */
+
+#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"
+
+PG_MODULE_MAGIC;
+
+PG_FUNCTION_INFO_V1(pgstattuple);
+PG_FUNCTION_INFO_V1(pgstattuple_v1_5);
+PG_FUNCTION_INFO_V1(pgstattuplebyid);
+PG_FUNCTION_INFO_V1(pgstattuplebyid_v1_5);
+
+/*
+ * struct pgstattuple_type
+ *
+ * tuple_percent, dead_tuple_percent and free_percent are computable,
+ * so not defined here.
+ */
+typedef struct pgstattuple_type
+{
+ uint64 table_len;
+ uint64 tuple_count;
+ uint64 tuple_len;
+ uint64 dead_tuple_count;
+ uint64 dead_tuple_len;
+ uint64 free_space; /* free/reusable space in bytes */
+} pgstattuple_type;
+
+typedef void (*pgstat_page) (pgstattuple_type *, Relation, BlockNumber,
+ BufferAccessStrategy);
+
+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);
+
+/*
+ * build_pgstattuple_type -- build a pgstattuple_type tuple
+ */
+static Datum
+build_pgstattuple_type(pgstattuple_type *stat, FunctionCallInfo fcinfo)
+{
+#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);
+}
+
+/* ----------
+ * pgstattuple:
+ * returns live/dead tuples info
+ *
+ * C FUNCTION definition
+ * pgstattuple(text) returns pgstattuple_type
+ *
+ * The superuser() check here must be kept as the library might be upgraded
+ * without the extension being upgraded, meaning that in pre-1.5 installations
+ * these functions could be called by any user.
+ * ----------
+ */
+
+Datum
+pgstattuple(PG_FUNCTION_ARGS)
+{
+ 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));
+}
+
+/*
+ * As of pgstattuple version 1.5, we no longer need to check if the user
+ * is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
+ * Users can then grant access to it based on their policies.
+ *
+ * Otherwise identical to pgstattuple (above).
+ */
+Datum
+pgstattuple_v1_5(PG_FUNCTION_ARGS)
+{
+ 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));
+}
+
+/* Must keep superuser() check, see above. */
+Datum
+pgstattuplebyid(PG_FUNCTION_ARGS)
+{
+ 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));
+}
+
+/* Remove superuser() check for 1.5 version, see above */
+Datum
+pgstattuplebyid_v1_5(PG_FUNCTION_ARGS)
+{
+ Oid relid = PG_GETARG_OID(0);
+ Relation rel;
+
+ /* open relation */
+ rel = relation_open(relid, AccessShareLock);
+
+ PG_RETURN_DATUM(pgstat_relation(rel, fcinfo));
+}
+
+/*
+ * pgstat_relation
+ */
+static Datum
+pgstat_relation(Relation rel, FunctionCallInfo fcinfo)
+{
+ 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)
+ {
+ /* see pgstatindex_impl */
+ if (!rel->rd_index->indisvalid)
+ ereport(ERROR,
+ (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("index \"%s\" is not valid",
+ RelationGetRelationName(rel))));
+
+ 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 */
+}
+
+/*
+ * pgstat_heap -- returns live/dead tuples info in a heap
+ */
+static Datum
+pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
+{
+ 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);
+}
+
+/*
+ * pgstat_btree_page -- check tuples in a btree page
+ */
+static void
+pgstat_btree_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno,
+ BufferAccessStrategy bstrategy)
+{
+ 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);
+}
+
+/*
+ * pgstat_hash_page -- check tuples in a hash page
+ */
+static void
+pgstat_hash_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno,
+ BufferAccessStrategy bstrategy)
+{
+ 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);
+}
+
+/*
+ * pgstat_gist_page -- check tuples in a gist page
+ */
+static void
+pgstat_gist_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno,
+ BufferAccessStrategy bstrategy)
+{
+ 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);
+}
+
+/*
+ * pgstat_index -- returns live/dead tuples info in a generic index
+ */
+static Datum
+pgstat_index(Relation rel, BlockNumber start, pgstat_page pagefn,
+ FunctionCallInfo fcinfo)
+{
+ 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);
+}
+
+/*
+ * pgstat_index_page -- for generic index page
+ */
+static void
+pgstat_index_page(pgstattuple_type *stat, Page page,
+ OffsetNumber minoff, OffsetNumber maxoff)
+{
+ 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);
+ }
+ }
+}
diff --git a/contrib/pgstattuple/pgstattuple.control b/contrib/pgstattuple/pgstattuple.control
new file mode 100644
index 0000000..6af4075
--- /dev/null
+++ b/contrib/pgstattuple/pgstattuple.control
@@ -0,0 +1,5 @@
+# pgstattuple extension
+comment = 'show tuple-level statistics'
+default_version = '1.5'
+module_pathname = '$libdir/pgstattuple'
+relocatable = true
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-13 23:35:44 +0000