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Clean up BeginCommand and related routines. BeginCommand and EndCommand

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are now both invoked once per received SQL command (raw parsetree) from
pg_exec_query_string.  BeginCommand is actually just an empty routine
at the moment --- all its former operations have been pushed into tuple
receiver setup routines in printtup.c.  This makes for a clean distinction
between BeginCommand/EndCommand (once per command) and the tuple receiver
setup/teardown routines (once per ExecutorRun call), whereas the old code
was quite ad hoc.  Along the way, clean up the calling conventions for
ExecutorRun a little bit.
This commit is contained in:
Tom Lane
2002-02-27 19:36:13 +00:00
parent e22c9c4475
commit 6779c55c22
15 changed files with 266 additions and 361 deletions
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80
src/backend/commands/command.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.155 2002/02/26 22:47:04 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.156 2002/02/27 19:34:38 tgl Exp $
*
* NOTES
* The PerformAddAttribute() code, like most of the relation
@@ -113,6 +113,7 @@ PerformPortalFetch(char *name,
QueryDesc *queryDesc;
EState *estate;
MemoryContext oldcontext;
ScanDirection direction;
CommandId savedId;
bool temp_desc = false;
@@ -145,6 +146,9 @@ PerformPortalFetch(char *name,
*/
oldcontext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
queryDesc = PortalGetQueryDesc(portal);
estate = PortalGetState(portal);
/*
* If the requested destination is not the same as the query's
* original destination, make a temporary QueryDesc with the proper
@@ -156,9 +160,6 @@ PerformPortalFetch(char *name,
* original dest. This is necessary since a FETCH command will pass
* dest = Remote, not knowing whether the cursor is binary or not.
*/
queryDesc = PortalGetQueryDesc(portal);
estate = PortalGetState(portal);
if (dest != queryDesc->dest &&
!(queryDesc->dest == RemoteInternal && dest == Remote))
{
@@ -170,19 +171,6 @@ PerformPortalFetch(char *name,
temp_desc = true;
}
/*
* Tell the destination to prepare to receive some tuples.
*/
BeginCommand(name,
queryDesc->operation,
PortalGetTupleDesc(portal),
false, /* portal fetches don't end up in
* relations */
false, /* this is a portal fetch, not a "retrieve
* portal" */
NULL, /* not used */
queryDesc->dest);
/*
* Restore the scanCommandId that was current when the cursor was
* opened. This ensures that we see the same tuples throughout the
@@ -194,47 +182,49 @@ PerformPortalFetch(char *name,
/*
* Determine which direction to go in, and check to see if we're
* already at the end of the available tuples in that direction. If
* so, do nothing. (This check exists because not all plan node types
* so, set the direction to NoMovement to avoid trying to fetch any
* tuples. (This check exists because not all plan node types
* are robust about being called again if they've already returned
* NULL once.) If it's OK to do the fetch, call the executor. Then,
* update the atStart/atEnd state depending on the number of tuples
* that were retrieved.
* NULL once.) Then call the executor (we must not skip this, because
* the destination needs to see a setup and shutdown even if no tuples
* are available). Finally, update the atStart/atEnd state depending
* on the number of tuples that were retrieved.
*/
if (forward)
{
if (!portal->atEnd)
{
ExecutorRun(queryDesc, estate, EXEC_FOR, (long) count);
if (portal->atEnd)
direction = NoMovementScanDirection;
else
direction = ForwardScanDirection;
if (estate->es_processed > 0)
portal->atStart = false; /* OK to back up now */
if (count <= 0 || (int) estate->es_processed < count)
portal->atEnd = true; /* we retrieved 'em all */
ExecutorRun(queryDesc, estate, direction, (long) count);
if (completionTag)
snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s %u",
(dest == None) ? "MOVE" : "FETCH",
estate->es_processed);
}
if (estate->es_processed > 0)
portal->atStart = false; /* OK to back up now */
if (count <= 0 || (int) estate->es_processed < count)
portal->atEnd = true; /* we retrieved 'em all */
}
else
{
if (!portal->atStart)
{
ExecutorRun(queryDesc, estate, EXEC_BACK, (long) count);
if (portal->atStart)
direction = NoMovementScanDirection;
else
direction = BackwardScanDirection;
if (estate->es_processed > 0)
portal->atEnd = false; /* OK to go forward now */
if (count <= 0 || (int) estate->es_processed < count)
portal->atStart = true; /* we retrieved 'em all */
ExecutorRun(queryDesc, estate, direction, (long) count);
if (completionTag)
snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s %u",
(dest == None) ? "MOVE" : "FETCH",
estate->es_processed);
}
if (estate->es_processed > 0)
portal->atEnd = false; /* OK to go forward now */
if (count <= 0 || (int) estate->es_processed < count)
portal->atStart = true; /* we retrieved 'em all */
}
/* Return command status if wanted */
if (completionTag)
snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s %u",
(dest == None) ? "MOVE" : "FETCH",
estate->es_processed);
/*
* Restore outer command ID.
*/