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Create core infrastructure for KNNGIST.

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This is a heavily revised version of builtin_knngist_core-0.9.  The
ordering operators are no longer mixed in with actual quals, which would
have confused not only humans but significant parts of the planner.
Instead, ordering operators are carried separately throughout planning and
execution.

Since the API for ambeginscan and amrescan functions had to be changed
anyway, this commit takes the opportunity to rationalize that a bit.
RelationGetIndexScan no longer forces a premature index_rescan call;
instead, callers of index_beginscan must call index_rescan too.  Aside from
making the AM-side initialization logic a bit less peculiar, this has the
advantage that we do not make a useless extra am_rescan call when there are
runtime key values.  AMs formerly could not assume that the key values
passed to amrescan were actually valid; now they can.

Teodor Sigaev and Tom Lane
This commit is contained in:
Tom Lane
2010-12-02 20:50:48 -05:00
parent d7e5d151da
commit d583f10b7e
40 changed files with 786 additions and 310 deletions
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40
src/backend/access/hash/hash.c
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@@ -366,12 +366,16 @@ Datum
hashbeginscan(PG_FUNCTION_ARGS)
{
Relation rel = (Relation) PG_GETARG_POINTER(0);
int keysz = PG_GETARG_INT32(1);
ScanKey scankey = (ScanKey) PG_GETARG_POINTER(2);
int nkeys = PG_GETARG_INT32(1);
int norderbys = PG_GETARG_INT32(2);
IndexScanDesc scan;
HashScanOpaque so;
scan = RelationGetIndexScan(rel, keysz, scankey);
/* no order by operators allowed */
Assert(norderbys == 0);
scan = RelationGetIndexScan(rel, nkeys, norderbys);
so = (HashScanOpaque) palloc(sizeof(HashScanOpaqueData));
so->hashso_bucket_valid = false;
so->hashso_bucket_blkno = 0;
@@ -396,26 +400,23 @@ hashrescan(PG_FUNCTION_ARGS)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
ScanKey scankey = (ScanKey) PG_GETARG_POINTER(1);
/* remaining arguments are ignored */
HashScanOpaque so = (HashScanOpaque) scan->opaque;
Relation rel = scan->indexRelation;
/* if we are called from beginscan, so is still NULL */
if (so)
{
/* release any pin we still hold */
if (BufferIsValid(so->hashso_curbuf))
_hash_dropbuf(rel, so->hashso_curbuf);
so->hashso_curbuf = InvalidBuffer;
/* release any pin we still hold */
if (BufferIsValid(so->hashso_curbuf))
_hash_dropbuf(rel, so->hashso_curbuf);
so->hashso_curbuf = InvalidBuffer;
/* release lock on bucket, too */
if (so->hashso_bucket_blkno)
_hash_droplock(rel, so->hashso_bucket_blkno, HASH_SHARE);
so->hashso_bucket_blkno = 0;
/* release lock on bucket, too */
if (so->hashso_bucket_blkno)
_hash_droplock(rel, so->hashso_bucket_blkno, HASH_SHARE);
so->hashso_bucket_blkno = 0;
/* set position invalid (this will cause _hash_first call) */
ItemPointerSetInvalid(&(so->hashso_curpos));
ItemPointerSetInvalid(&(so->hashso_heappos));
}
/* set position invalid (this will cause _hash_first call) */
ItemPointerSetInvalid(&(so->hashso_curpos));
ItemPointerSetInvalid(&(so->hashso_heappos));
/* Update scan key, if a new one is given */
if (scankey && scan->numberOfKeys > 0)
@@ -423,8 +424,7 @@ hashrescan(PG_FUNCTION_ARGS)
memmove(scan->keyData,
scankey,
scan->numberOfKeys * sizeof(ScanKeyData));
if (so)
so->hashso_bucket_valid = false;
so->hashso_bucket_valid = false;
}
PG_RETURN_VOID();