database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-29 10:41:53 +03:00
Code Activity

Ensure that a cursor is scanned under the same scanCommandId it was

Browse Source 
originally created with, so that the set of visible tuples does not
change as a result of other activity.  This essentially makes PG cursors
INSENSITIVE per the SQL92 definition.  See bug report of 13-Feb-02.
This commit is contained in:
Tom Lane
2002-02-14 15:24:10 +00:00
parent 1392042346
commit 3576820e78
4 changed files with 48 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
src/backend/executor/spi.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.64 2002/01/03 20:30:47 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.65 2002/02/14 15:24:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -740,9 +740,9 @@ SPI_cursor_open(char *name, void *plan, Datum *Values, char *Nulls)
_SPI_current->processed = 0;
_SPI_current->tuptable = NULL;
/* Make up a portal name if none given */
if (name == NULL)
{
/* Make up a portal name if none given */
for (;;)
{
unnamed_portal_count++;
@ -755,11 +755,13 @@ SPI_cursor_open(char *name, void *plan, Datum *Values, char *Nulls)
name = portalname;
}
/* Ensure the portal doesn't exist already */
portal = GetPortalByName(name);
if (portal != NULL)
elog(ERROR, "cursor \"%s\" already in use", name);
else
{
/* Ensure the portal doesn't exist already */
portal = GetPortalByName(name);
if (portal != NULL)
elog(ERROR, "cursor \"%s\" already in use", name);
}
/* Create the portal */
portal = CreatePortal(name);
@ -1228,6 +1230,7 @@ _SPI_cursor_operation(Portal portal, bool forward, int count,
QueryDesc *querydesc;
EState *estate;
MemoryContext oldcontext;
CommandId savedId;
CommandDest olddest;
/* Check that the portal is valid */
@ -1245,6 +1248,7 @@ _SPI_cursor_operation(Portal portal, bool forward, int count,
/* Switch to the portals memory context */
oldcontext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
querydesc = PortalGetQueryDesc(portal);
estate = PortalGetState(portal);
@ -1253,6 +1257,14 @@ _SPI_cursor_operation(Portal portal, bool forward, int count,
olddest = querydesc->dest;
querydesc->dest = dest;
/*
* Restore the scanCommandId that was current when the cursor was
* opened. This ensures that we see the same tuples throughout the
* execution of the cursor.
*/
savedId = GetScanCommandId();
SetScanCommandId(PortalGetCommandId(portal));
/* Run the executor like PerformPortalFetch and remember states */
if (forward)
{
@ -1279,6 +1291,11 @@ _SPI_cursor_operation(Portal portal, bool forward, int count,
}
}
/*
* Restore outer command ID.
*/
SetScanCommandId(savedId);
/* Restore the old command destination and switch back to callers */
/* memory context */
querydesc->dest = olddest;