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First phase of plan-invalidation project: create a plan cache management

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module and teach PREPARE and protocol-level prepared statements to use it.
In service of this, rearrange utility-statement processing so that parse
analysis does not assume table schemas can't change before execution for
utility statements (necessary because we don't attempt to re-acquire locks
for utility statements when reusing a stored plan).  This requires some
refactoring of the ProcessUtility API, but it ends up cleaner anyway,
for instance we can get rid of the QueryContext global.

Still to do: fix up SPI and related code to use the plan cache; I'm tempted to
try to make SQL functions use it too.  Also, there are at least some aspects
of system state that we want to ensure remain the same during a replan as in
the original processing; search_path certainly ought to behave that way for
instance, and perhaps there are others.
This commit is contained in:
Tom Lane
2007-03-13 00:33:44 +00:00
parent f84308f195
commit b9527e9840
61 changed files with 2478 additions and 1354 deletions
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74
src/backend/tcop/pquery.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.114 2007/02/20 17:32:16 tgl Exp $
* $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.115 2007/03/13 00:33:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -36,14 +36,14 @@ static void ProcessQuery(PlannedStmt *plan,
ParamListInfo params,
DestReceiver *dest,
char *completionTag);
static void FillPortalStore(Portal portal);
static void FillPortalStore(Portal portal, bool isTopLevel);
static uint32 RunFromStore(Portal portal, ScanDirection direction, long count,
DestReceiver *dest);
static long PortalRunSelect(Portal portal, bool forward, long count,
DestReceiver *dest);
static void PortalRunUtility(Portal portal, Node *utilityStmt,
static void PortalRunUtility(Portal portal, Node *utilityStmt, bool isTopLevel,
DestReceiver *dest, char *completionTag);
static void PortalRunMulti(Portal portal,
static void PortalRunMulti(Portal portal, bool isTopLevel,
DestReceiver *dest, DestReceiver *altdest,
char *completionTag);
static long DoPortalRunFetch(Portal portal,
@ -148,8 +148,7 @@ ProcessQuery(PlannedStmt *plan,
{
QueryDesc *queryDesc;
ereport(DEBUG3,
(errmsg_internal("ProcessQuery")));
elog(DEBUG3, "ProcessQuery");
/*
* Must always set snapshot for plannable queries. Note we assume that
@ -232,8 +231,7 @@ ProcessQuery(PlannedStmt *plan,
* Select portal execution strategy given the intended statement list.
*
* The list elements can be Querys, PlannedStmts, or utility statements.
* That's more general than portals need, but we use this for prepared
* statements as well.
* That's more general than portals need, but plancache.c uses this too.
*
* See the comments in portal.h.
*/
@ -358,8 +356,7 @@ FetchPortalTargetList(Portal portal)
* Returns NIL if the statement doesn't have a determinable targetlist.
*
* This can be applied to a Query, a PlannedStmt, or a utility statement.
* That's more general than portals need, but we use this for prepared
* statements as well.
* That's more general than portals need, but plancache.c uses this too.
*
* Note: do not modify the result.
*
@ -452,11 +449,10 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot)
int eflags;
AssertArg(PortalIsValid(portal));
AssertState(portal->queryContext != NULL); /* query defined? */
AssertState(portal->status == PORTAL_NEW); /* else extra PortalStart */
AssertState(portal->status == PORTAL_DEFINED);
/*
* Set up global portal context pointers. (Should we set QueryContext?)
* Set up global portal context pointers.
*/
saveActivePortal = ActivePortal;
saveActiveSnapshot = ActiveSnapshot;
@ -683,6 +679,9 @@ PortalSetResultFormat(Portal portal, int nFormats, int16 *formats)
* interpreted as "all rows". Note that count is ignored in multi-query
* situations, where we always run the portal to completion.
*
* isTopLevel: true if query is being executed at backend "top level"
* (that is, directly from a client command message)
*
* dest: where to send output of primary (canSetTag) query
*
* altdest: where to send output of non-primary queries
@ -695,7 +694,7 @@ PortalSetResultFormat(Portal portal, int nFormats, int16 *formats)
* suspended due to exhaustion of the count parameter.
*/
bool
PortalRun(Portal portal, long count,
PortalRun(Portal portal, long count, bool isTopLevel,
DestReceiver *dest, DestReceiver *altdest,
char *completionTag)
{
@ -706,7 +705,6 @@ PortalRun(Portal portal, long count,
Snapshot saveActiveSnapshot;
ResourceOwner saveResourceOwner;
MemoryContext savePortalContext;
MemoryContext saveQueryContext;
MemoryContext saveMemoryContext;
AssertArg(PortalIsValid(portal));
@ -717,8 +715,7 @@ PortalRun(Portal portal, long count,
if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
{
ereport(DEBUG3,
(errmsg_internal("PortalRun")));
elog(DEBUG3, "PortalRun");
/* PORTAL_MULTI_QUERY logs its own stats per query */
ResetUsage();
}
@ -752,7 +749,6 @@ PortalRun(Portal portal, long count,
saveActiveSnapshot = ActiveSnapshot;
saveResourceOwner = CurrentResourceOwner;
savePortalContext = PortalContext;
saveQueryContext = QueryContext;
saveMemoryContext = CurrentMemoryContext;
PG_TRY();
{
@ -760,7 +756,6 @@ PortalRun(Portal portal, long count,
ActiveSnapshot = NULL; /* will be set later */
CurrentResourceOwner = portal->resowner;
PortalContext = PortalGetHeapMemory(portal);
QueryContext = portal->queryContext;
MemoryContextSwitchTo(PortalContext);
@ -790,7 +785,7 @@ PortalRun(Portal portal, long count,
* results in the portal's tuplestore.
*/
if (!portal->holdStore)
FillPortalStore(portal);
FillPortalStore(portal, isTopLevel);
/*
* Now fetch desired portion of results.
@ -811,7 +806,8 @@ PortalRun(Portal portal, long count,
break;
case PORTAL_MULTI_QUERY:
PortalRunMulti(portal, dest, altdest, completionTag);
PortalRunMulti(portal, isTopLevel,
dest, altdest, completionTag);
/* Prevent portal's commands from being re-executed */
portal->status = PORTAL_DONE;
@ -844,7 +840,6 @@ PortalRun(Portal portal, long count,
else
CurrentResourceOwner = saveResourceOwner;
PortalContext = savePortalContext;
QueryContext = saveQueryContext;
PG_RE_THROW();
}
@ -861,7 +856,6 @@ PortalRun(Portal portal, long count,
else
CurrentResourceOwner = saveResourceOwner;
PortalContext = savePortalContext;
QueryContext = saveQueryContext;
if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
ShowUsage("EXECUTOR STATISTICS");
@ -1025,7 +1019,7 @@ PortalRunSelect(Portal portal,
* This is used for PORTAL_ONE_RETURNING and PORTAL_UTIL_SELECT cases only.
*/
static void
FillPortalStore(Portal portal)
FillPortalStore(Portal portal, bool isTopLevel)
{
DestReceiver *treceiver;
char completionTag[COMPLETION_TAG_BUFSIZE];
@ -1044,12 +1038,13 @@ FillPortalStore(Portal portal)
* MULTI_QUERY case, but send the primary query's output to the
* tuplestore. Auxiliary query outputs are discarded.
*/
PortalRunMulti(portal, treceiver, None_Receiver, completionTag);
PortalRunMulti(portal, isTopLevel,
treceiver, None_Receiver, completionTag);
break;
case PORTAL_UTIL_SELECT:
PortalRunUtility(portal, (Node *) linitial(portal->stmts),
treceiver, completionTag);
isTopLevel, treceiver, completionTag);
break;
default:
@ -1137,11 +1132,10 @@ RunFromStore(Portal portal, ScanDirection direction, long count,
* Execute a utility statement inside a portal.
*/
static void
PortalRunUtility(Portal portal, Node *utilityStmt,
PortalRunUtility(Portal portal, Node *utilityStmt, bool isTopLevel,
DestReceiver *dest, char *completionTag)
{
ereport(DEBUG3,
(errmsg_internal("ProcessUtility")));
elog(DEBUG3, "ProcessUtility");
/*
* Set snapshot if utility stmt needs one. Most reliable way to do this
@ -1173,7 +1167,12 @@ PortalRunUtility(Portal portal, Node *utilityStmt,
else
ActiveSnapshot = NULL;
ProcessUtility(utilityStmt, portal->portalParams, dest, completionTag);
ProcessUtility(utilityStmt,
portal->sourceText,
portal->portalParams,
isTopLevel,
dest,
completionTag);
/* Some utility statements may change context on us */
MemoryContextSwitchTo(PortalGetHeapMemory(portal));
@ -1189,7 +1188,7 @@ PortalRunUtility(Portal portal, Node *utilityStmt,
* or non-SELECT-like queries)
*/
static void
PortalRunMulti(Portal portal,
PortalRunMulti(Portal portal, bool isTopLevel,
DestReceiver *dest, DestReceiver *altdest,
char *completionTag)
{
@ -1260,9 +1259,9 @@ PortalRunMulti(Portal portal,
* portal.
*/
if (list_length(portal->stmts) == 1)
PortalRunUtility(portal, stmt, dest, completionTag);
PortalRunUtility(portal, stmt, isTopLevel, dest, completionTag);
else
PortalRunUtility(portal, stmt, altdest, NULL);
PortalRunUtility(portal, stmt, isTopLevel, altdest, NULL);
}
/*
@ -1305,6 +1304,8 @@ PortalRunMulti(Portal portal,
* PortalRunFetch
* Variant form of PortalRun that supports SQL FETCH directions.
*
* Note: we presently assume that no callers of this want isTopLevel = true.
*
* Returns number of rows processed (suitable for use in result tag)
*/
long
@ -1318,7 +1319,6 @@ PortalRunFetch(Portal portal,
Snapshot saveActiveSnapshot;
ResourceOwner saveResourceOwner;
MemoryContext savePortalContext;
MemoryContext saveQueryContext;
MemoryContext oldContext;
AssertArg(PortalIsValid(portal));
@ -1339,14 +1339,12 @@ PortalRunFetch(Portal portal,
saveActiveSnapshot = ActiveSnapshot;
saveResourceOwner = CurrentResourceOwner;
savePortalContext = PortalContext;
saveQueryContext = QueryContext;
PG_TRY();
{
ActivePortal = portal;
ActiveSnapshot = NULL; /* will be set later */
CurrentResourceOwner = portal->resowner;
PortalContext = PortalGetHeapMemory(portal);
QueryContext = portal->queryContext;
oldContext = MemoryContextSwitchTo(PortalContext);
@ -1364,7 +1362,7 @@ PortalRunFetch(Portal portal,
* results in the portal's tuplestore.
*/
if (!portal->holdStore)
FillPortalStore(portal);
FillPortalStore(portal, false /* isTopLevel */);
/*
* Now fetch desired portion of results.
@ -1388,7 +1386,6 @@ PortalRunFetch(Portal portal,
ActiveSnapshot = saveActiveSnapshot;
CurrentResourceOwner = saveResourceOwner;
PortalContext = savePortalContext;
QueryContext = saveQueryContext;
PG_RE_THROW();
}
@ -1403,7 +1400,6 @@ PortalRunFetch(Portal portal,
ActiveSnapshot = saveActiveSnapshot;
CurrentResourceOwner = saveResourceOwner;
PortalContext = savePortalContext;
QueryContext = saveQueryContext;
return result;
}