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4623d71443
Applying pg_freespacemap() to a relation lacking storage (such as a view) caused an assertion failure, although there was no ill effect in non-assert builds. Add an error check for that case. Bug: #18866 Reported-by: Robins Tharakan <tharakan@gmail.com> Author: Tender Wang <tndrwang@gmail.com> Reviewed-by: Euler Taveira <euler@eulerto.com> Discussion: https://postgr.es/m/18866-d68926d0f1c72d44@postgresql.org Backpatch-through: 13
54 lines
1.3 KiB
C
54 lines
1.3 KiB
C
/*-------------------------------------------------------------------------
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*
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* pg_freespacemap.c
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* display contents of a free space map
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*
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* contrib/pg_freespacemap/pg_freespacemap.c
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/relation.h"
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#include "fmgr.h"
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#include "storage/freespace.h"
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#include "utils/rel.h"
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PG_MODULE_MAGIC_EXT(
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.name = "pg_freespacemap",
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.version = PG_VERSION
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);
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/*
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* Returns the amount of free space on a given page, according to the
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* free space map.
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*/
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PG_FUNCTION_INFO_V1(pg_freespace);
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Datum
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pg_freespace(PG_FUNCTION_ARGS)
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{
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Oid relid = PG_GETARG_OID(0);
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int64 blkno = PG_GETARG_INT64(1);
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int16 freespace;
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Relation rel;
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rel = relation_open(relid, AccessShareLock);
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if (!RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
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ereport(ERROR,
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(errcode(ERRCODE_WRONG_OBJECT_TYPE),
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errmsg("relation \"%s\" does not have storage",
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RelationGetRelationName(rel)),
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errdetail_relkind_not_supported(rel->rd_rel->relkind)));
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if (blkno < 0 || blkno > MaxBlockNumber)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("invalid block number")));
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freespace = GetRecordedFreeSpace(rel, blkno);
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relation_close(rel, AccessShareLock);
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PG_RETURN_INT16(freespace);
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}
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