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591 lines
15 KiB
C
591 lines
15 KiB
C
/*
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* contrib/pgstattuple/pgstattuple.c
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*
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* Copyright (c) 2001,2002 Tatsuo Ishii
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*
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* Permission to use, copy, modify, and distribute this software and
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* its documentation for any purpose, without fee, and without a
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* written agreement is hereby granted, provided that the above
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* copyright notice and this paragraph and the following two
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* paragraphs appear in all copies.
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*
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
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* INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
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* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
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* DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
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* IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
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* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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#include "postgres.h"
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#include "access/gist_private.h"
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#include "access/hash.h"
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#include "access/heapam.h"
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#include "access/nbtree.h"
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#include "access/relscan.h"
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#include "access/tableam.h"
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#include "catalog/namespace.h"
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#include "catalog/pg_am_d.h"
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#include "funcapi.h"
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#include "miscadmin.h"
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#include "storage/bufmgr.h"
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#include "storage/lmgr.h"
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#include "utils/builtins.h"
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#include "utils/varlena.h"
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PG_MODULE_MAGIC;
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PG_FUNCTION_INFO_V1(pgstattuple);
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PG_FUNCTION_INFO_V1(pgstattuple_v1_5);
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PG_FUNCTION_INFO_V1(pgstattuplebyid);
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PG_FUNCTION_INFO_V1(pgstattuplebyid_v1_5);
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/*
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* struct pgstattuple_type
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*
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* tuple_percent, dead_tuple_percent and free_percent are computable,
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* so not defined here.
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*/
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typedef struct pgstattuple_type
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{
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uint64 table_len;
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uint64 tuple_count;
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uint64 tuple_len;
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uint64 dead_tuple_count;
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uint64 dead_tuple_len;
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uint64 free_space; /* free/reusable space in bytes */
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} pgstattuple_type;
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typedef void (*pgstat_page) (pgstattuple_type *, Relation, BlockNumber,
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BufferAccessStrategy);
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static Datum build_pgstattuple_type(pgstattuple_type *stat,
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FunctionCallInfo fcinfo);
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static Datum pgstat_relation(Relation rel, FunctionCallInfo fcinfo);
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static Datum pgstat_heap(Relation rel, FunctionCallInfo fcinfo);
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static void pgstat_btree_page(pgstattuple_type *stat,
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Relation rel, BlockNumber blkno,
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BufferAccessStrategy bstrategy);
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static void pgstat_hash_page(pgstattuple_type *stat,
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Relation rel, BlockNumber blkno,
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BufferAccessStrategy bstrategy);
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static void pgstat_gist_page(pgstattuple_type *stat,
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Relation rel, BlockNumber blkno,
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BufferAccessStrategy bstrategy);
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static Datum pgstat_index(Relation rel, BlockNumber start,
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pgstat_page pagefn, FunctionCallInfo fcinfo);
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static void pgstat_index_page(pgstattuple_type *stat, Page page,
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OffsetNumber minoff, OffsetNumber maxoff);
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/*
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* build_pgstattuple_type -- build a pgstattuple_type tuple
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*/
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static Datum
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build_pgstattuple_type(pgstattuple_type *stat, FunctionCallInfo fcinfo)
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{
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#define NCOLUMNS 9
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#define NCHARS 314
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HeapTuple tuple;
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char *values[NCOLUMNS];
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char values_buf[NCOLUMNS][NCHARS];
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int i;
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double tuple_percent;
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double dead_tuple_percent;
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double free_percent; /* free/reusable space in % */
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TupleDesc tupdesc;
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AttInMetadata *attinmeta;
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/* Build a tuple descriptor for our result type */
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if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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/*
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* Generate attribute metadata needed later to produce tuples from raw C
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* strings
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*/
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attinmeta = TupleDescGetAttInMetadata(tupdesc);
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if (stat->table_len == 0)
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{
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tuple_percent = 0.0;
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dead_tuple_percent = 0.0;
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free_percent = 0.0;
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}
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else
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{
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tuple_percent = 100.0 * stat->tuple_len / stat->table_len;
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dead_tuple_percent = 100.0 * stat->dead_tuple_len / stat->table_len;
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free_percent = 100.0 * stat->free_space / stat->table_len;
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}
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/*
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* Prepare a values array for constructing the tuple. This should be an
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* array of C strings which will be processed later by the appropriate
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* "in" functions.
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*/
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for (i = 0; i < NCOLUMNS; i++)
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values[i] = values_buf[i];
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i = 0;
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snprintf(values[i++], NCHARS, INT64_FORMAT, stat->table_len);
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snprintf(values[i++], NCHARS, INT64_FORMAT, stat->tuple_count);
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snprintf(values[i++], NCHARS, INT64_FORMAT, stat->tuple_len);
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snprintf(values[i++], NCHARS, "%.2f", tuple_percent);
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snprintf(values[i++], NCHARS, INT64_FORMAT, stat->dead_tuple_count);
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snprintf(values[i++], NCHARS, INT64_FORMAT, stat->dead_tuple_len);
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snprintf(values[i++], NCHARS, "%.2f", dead_tuple_percent);
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snprintf(values[i++], NCHARS, INT64_FORMAT, stat->free_space);
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snprintf(values[i++], NCHARS, "%.2f", free_percent);
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/* build a tuple */
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tuple = BuildTupleFromCStrings(attinmeta, values);
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/* make the tuple into a datum */
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return HeapTupleGetDatum(tuple);
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}
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/* ----------
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* pgstattuple:
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* returns live/dead tuples info
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*
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* C FUNCTION definition
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* pgstattuple(text) returns pgstattuple_type
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*
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* The superuser() check here must be kept as the library might be upgraded
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* without the extension being upgraded, meaning that in pre-1.5 installations
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* these functions could be called by any user.
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* ----------
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*/
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Datum
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pgstattuple(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_PP(0);
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RangeVar *relrv;
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Relation rel;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser to use pgstattuple functions")));
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/* open relation */
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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PG_RETURN_DATUM(pgstat_relation(rel, fcinfo));
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}
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/*
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* As of pgstattuple version 1.5, we no longer need to check if the user
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* is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
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* Users can then grant access to it based on their policies.
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*
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* Otherwise identical to pgstattuple (above).
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*/
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Datum
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pgstattuple_v1_5(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_PP(0);
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RangeVar *relrv;
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Relation rel;
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/* open relation */
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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PG_RETURN_DATUM(pgstat_relation(rel, fcinfo));
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}
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/* Must keep superuser() check, see above. */
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Datum
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pgstattuplebyid(PG_FUNCTION_ARGS)
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{
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Oid relid = PG_GETARG_OID(0);
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Relation rel;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser to use pgstattuple functions")));
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/* open relation */
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rel = relation_open(relid, AccessShareLock);
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PG_RETURN_DATUM(pgstat_relation(rel, fcinfo));
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}
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/* Remove superuser() check for 1.5 version, see above */
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Datum
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pgstattuplebyid_v1_5(PG_FUNCTION_ARGS)
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{
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Oid relid = PG_GETARG_OID(0);
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Relation rel;
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/* open relation */
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rel = relation_open(relid, AccessShareLock);
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PG_RETURN_DATUM(pgstat_relation(rel, fcinfo));
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}
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/*
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* pgstat_relation
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*/
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static Datum
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pgstat_relation(Relation rel, FunctionCallInfo fcinfo)
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{
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const char *err;
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/*
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* Reject attempts to read non-local temporary relations; we would be
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* likely to get wrong data since we have no visibility into the owning
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* session's local buffers.
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*/
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if (RELATION_IS_OTHER_TEMP(rel))
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("cannot access temporary tables of other sessions")));
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switch (rel->rd_rel->relkind)
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{
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case RELKIND_RELATION:
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case RELKIND_MATVIEW:
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case RELKIND_TOASTVALUE:
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case RELKIND_SEQUENCE:
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return pgstat_heap(rel, fcinfo);
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case RELKIND_INDEX:
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switch (rel->rd_rel->relam)
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{
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case BTREE_AM_OID:
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return pgstat_index(rel, BTREE_METAPAGE + 1,
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pgstat_btree_page, fcinfo);
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case HASH_AM_OID:
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return pgstat_index(rel, HASH_METAPAGE + 1,
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pgstat_hash_page, fcinfo);
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case GIST_AM_OID:
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return pgstat_index(rel, GIST_ROOT_BLKNO + 1,
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pgstat_gist_page, fcinfo);
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case GIN_AM_OID:
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err = "gin index";
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break;
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case SPGIST_AM_OID:
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err = "spgist index";
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break;
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case BRIN_AM_OID:
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err = "brin index";
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break;
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default:
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err = "unknown index";
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break;
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}
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break;
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case RELKIND_VIEW:
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err = "view";
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break;
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case RELKIND_COMPOSITE_TYPE:
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err = "composite type";
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break;
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case RELKIND_FOREIGN_TABLE:
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err = "foreign table";
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break;
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case RELKIND_PARTITIONED_TABLE:
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err = "partitioned table";
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break;
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case RELKIND_PARTITIONED_INDEX:
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err = "partitioned index";
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break;
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default:
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err = "unknown";
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break;
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}
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("\"%s\" (%s) is not supported",
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RelationGetRelationName(rel), err)));
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return 0; /* should not happen */
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}
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/*
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* pgstat_heap -- returns live/dead tuples info in a heap
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*/
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static Datum
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pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
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{
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TableScanDesc scan;
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HeapScanDesc hscan;
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HeapTuple tuple;
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BlockNumber nblocks;
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BlockNumber block = 0; /* next block to count free space in */
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BlockNumber tupblock;
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Buffer buffer;
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pgstattuple_type stat = {0};
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SnapshotData SnapshotDirty;
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if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("only heap AM is supported")));
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/* Disable syncscan because we assume we scan from block zero upwards */
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scan = table_beginscan_strat(rel, SnapshotAny, 0, NULL, true, false);
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hscan = (HeapScanDesc) scan;
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InitDirtySnapshot(SnapshotDirty);
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nblocks = hscan->rs_nblocks; /* # blocks to be scanned */
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/* scan the relation */
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while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
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{
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CHECK_FOR_INTERRUPTS();
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/* must hold a buffer lock to call HeapTupleSatisfiesVisibility */
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LockBuffer(hscan->rs_cbuf, BUFFER_LOCK_SHARE);
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if (HeapTupleSatisfiesVisibility(tuple, &SnapshotDirty, hscan->rs_cbuf))
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{
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stat.tuple_len += tuple->t_len;
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stat.tuple_count++;
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}
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else
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{
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stat.dead_tuple_len += tuple->t_len;
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stat.dead_tuple_count++;
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}
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LockBuffer(hscan->rs_cbuf, BUFFER_LOCK_UNLOCK);
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/*
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* To avoid physically reading the table twice, try to do the
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* free-space scan in parallel with the heap scan. However,
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* heap_getnext may find no tuples on a given page, so we cannot
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* simply examine the pages returned by the heap scan.
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*/
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tupblock = ItemPointerGetBlockNumber(&tuple->t_self);
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while (block <= tupblock)
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{
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CHECK_FOR_INTERRUPTS();
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buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block,
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RBM_NORMAL, hscan->rs_strategy);
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LockBuffer(buffer, BUFFER_LOCK_SHARE);
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stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
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UnlockReleaseBuffer(buffer);
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block++;
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}
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}
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while (block < nblocks)
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{
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CHECK_FOR_INTERRUPTS();
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buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block,
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RBM_NORMAL, hscan->rs_strategy);
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LockBuffer(buffer, BUFFER_LOCK_SHARE);
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stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
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UnlockReleaseBuffer(buffer);
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block++;
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}
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table_endscan(scan);
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relation_close(rel, AccessShareLock);
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stat.table_len = (uint64) nblocks * BLCKSZ;
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return build_pgstattuple_type(&stat, fcinfo);
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}
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/*
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* pgstat_btree_page -- check tuples in a btree page
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*/
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static void
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pgstat_btree_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno,
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BufferAccessStrategy bstrategy)
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{
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Buffer buf;
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Page page;
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buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy);
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LockBuffer(buf, BT_READ);
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page = BufferGetPage(buf);
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/* Page is valid, see what to do with it */
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if (PageIsNew(page))
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{
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/* fully empty page */
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stat->free_space += BLCKSZ;
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}
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else
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{
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BTPageOpaque opaque;
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opaque = (BTPageOpaque) PageGetSpecialPointer(page);
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if (P_IGNORE(opaque))
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{
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/* deleted or half-dead page */
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stat->free_space += BLCKSZ;
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}
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else if (P_ISLEAF(opaque))
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{
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pgstat_index_page(stat, page, P_FIRSTDATAKEY(opaque),
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PageGetMaxOffsetNumber(page));
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}
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else
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{
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/* internal page */
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}
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}
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_bt_relbuf(rel, buf);
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}
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/*
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* pgstat_hash_page -- check tuples in a hash page
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*/
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static void
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pgstat_hash_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno,
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BufferAccessStrategy bstrategy)
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{
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Buffer buf;
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Page page;
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buf = _hash_getbuf_with_strategy(rel, blkno, HASH_READ, 0, bstrategy);
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page = BufferGetPage(buf);
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if (PageGetSpecialSize(page) == MAXALIGN(sizeof(HashPageOpaqueData)))
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{
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HashPageOpaque opaque;
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opaque = (HashPageOpaque) PageGetSpecialPointer(page);
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switch (opaque->hasho_flag & LH_PAGE_TYPE)
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{
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case LH_UNUSED_PAGE:
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stat->free_space += BLCKSZ;
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break;
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case LH_BUCKET_PAGE:
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case LH_OVERFLOW_PAGE:
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pgstat_index_page(stat, page, FirstOffsetNumber,
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PageGetMaxOffsetNumber(page));
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break;
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case LH_BITMAP_PAGE:
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case LH_META_PAGE:
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default:
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break;
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}
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}
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else
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{
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/* maybe corrupted */
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}
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_hash_relbuf(rel, buf);
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}
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/*
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* pgstat_gist_page -- check tuples in a gist page
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*/
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static void
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pgstat_gist_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno,
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BufferAccessStrategy bstrategy)
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{
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Buffer buf;
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Page page;
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buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy);
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LockBuffer(buf, GIST_SHARE);
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gistcheckpage(rel, buf);
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page = BufferGetPage(buf);
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if (GistPageIsLeaf(page))
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{
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pgstat_index_page(stat, page, FirstOffsetNumber,
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PageGetMaxOffsetNumber(page));
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}
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else
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{
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/* root or node */
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}
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UnlockReleaseBuffer(buf);
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}
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/*
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* pgstat_index -- returns live/dead tuples info in a generic index
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*/
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static Datum
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pgstat_index(Relation rel, BlockNumber start, pgstat_page pagefn,
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FunctionCallInfo fcinfo)
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{
|
|
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);
|
|
}
|
|
}
|
|
}
|