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Invent ResourceOwner mechanism as per my recent proposal, and use it to

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keep track of portal-related resources separately from transaction-related
resources.  This allows cursors to work in a somewhat sane fashion with
nested transactions.  For now, cursor behavior is non-subtransactional,
that is a cursor's state does not roll back if you abort a subtransaction
that fetched from the cursor.  We might want to change that later.
This commit is contained in:
Tom Lane
2004-07-17 03:32:14 +00:00
parent f4c069ca8f
commit fe548629c5
41 changed files with 2086 additions and 1192 deletions
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43
src/backend/access/hash/hashscan.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashscan.c,v 1.34 2004/07/01 00:49:29 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashscan.c,v 1.35 2004/07/17 03:27:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -16,12 +16,13 @@
#include "postgres.h"
#include "access/hash.h"
#include "utils/resowner.h"
typedef struct HashScanListData
{
IndexScanDesc hashsl_scan;
TransactionId hashsl_creatingXid;
ResourceOwner hashsl_owner;
struct HashScanListData *hashsl_next;
} HashScanListData;
@@ -31,52 +32,28 @@ static HashScanList HashScans = NULL;
/*
* AtEOXact_hash() --- clean up hash subsystem at xact abort or commit.
* ReleaseResources_hash() --- clean up hash subsystem resources.
*
* This is here because it needs to touch this module's static var HashScans.
*/
void
AtEOXact_hash(void)
{
/*
* Note: these actions should only be necessary during xact abort; but
* they can't hurt during a commit.
*/
/*
* Reset the active-scans list to empty. We do not need to free the
* list elements, because they're all palloc()'d, so they'll go away
* at end of transaction anyway.
*/
HashScans = NULL;
}
/*
* AtEOSubXact_hash() --- clean up hash subsystem at subxact abort or commit.
*
* This is here because it needs to touch this module's static var HashScans.
*/
void
AtEOSubXact_hash(TransactionId childXid)
ReleaseResources_hash(void)
{
HashScanList l;
HashScanList prev;
HashScanList next;
/*
* Note: these actions should only be necessary during xact abort; but
* they can't hurt during a commit.
*/
/*
* Forget active scans that were started in this subtransaction.
* Note: this should be a no-op during normal query shutdown.
* However, in an abort situation ExecutorEnd is not called and so
* there may be open index scans to clean up.
*/
prev = NULL;
for (l = HashScans; l != NULL; l = next)
{
next = l->hashsl_next;
if (l->hashsl_creatingXid == childXid)
if (l->hashsl_owner == CurrentResourceOwner)
{
if (prev == NULL)
HashScans = next;
@@ -101,7 +78,7 @@ _hash_regscan(IndexScanDesc scan)
new_el = (HashScanList) palloc(sizeof(HashScanListData));
new_el->hashsl_scan = scan;
new_el->hashsl_creatingXid = GetCurrentTransactionId();
new_el->hashsl_owner = CurrentResourceOwner;
new_el->hashsl_next = HashScans;
HashScans = new_el;
}