*

*

* IDENTIFICATION

* $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.56 1999/10/11 06:28:27 inoue Exp $

* $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.57 1999/10/30 23:10:21 tgl Exp $

*

*

* INTERFACE ROUTINES

unsigned nkeys,

ScanKey key)

{

if (!RelationGetNumberOfBlocks(relation))

/* ----------------

*Make sure we have up-to-date idea of number of blocks in relation.

*It is sufficient to do this once at scan start, since any tuples

*added while the scan is in progress will be invisible to my

*transaction anyway...

* ----------------

*/

relation->rd_nblocks = RelationGetNumberOfBlocks(relation);

if (relation->rd_nblocks == 0)

{

/* ----------------

*relation is empty

*/

scan = (HeapScanDesc) palloc(sizeof(HeapScanDescData));

relation->rd_nblocks = smgrnblocks(DEFAULT_SMGR, relation);

scan->rs_rd = relation;

scan->rs_atend = atend;

scan->rs_snapshot = snapshot;

scan->rs_nkeys = (short) nkeys;

if (nkeys)

/*

* we do this here instead of in initscan() because heap_rescan

* also calls initscan() and we don't want to allocate memory

initscan(scan, relation, atend, nkeys, key);

scan->rs_atend = atend;

scan->rs_snapshot = snapshot;

scan->rs_nkeys = (short) nkeys;

return scan;

}

*reinitialize scan descriptor

* ----------------

*/

initscan(scan, scan->rs_rd, scanFromEnd, scan->rs_nkeys, key);

scan->rs_atend = (bool) scanFromEnd;

initscan(scan, scan->rs_rd, scanFromEnd, scan->rs_nkeys, key);

}

/* ----------------

Snapshot snapshot,

ItemPointer tid)

{

ItemIdlp;

ItemIdlp = NULL;

Bufferbuffer;

PageHeaderdp;

OffsetNumberoffnum;