* doesn't actually run the executor for them.
*
*
- * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.79 2005/05/11 18:05:37 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.101 2007/04/12 06:53:48 neilc Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
-#include "miscadmin.h"
+#include "access/heapam.h"
+#include "access/xact.h"
+#include "catalog/pg_type.h"
#include "commands/portalcmds.h"
-#include "executor/executor.h"
-#include "utils/hsearch.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "utils/builtins.h"
#include "utils/memutils.h"
-#include "utils/portal.h"
/*
* Estimate of the maximum number of open portals a user would have,
#define PortalHashTableLookup(NAME, PORTAL) \
do { \
- PortalHashEnt *hentry; char key[MAX_PORTALNAME_LEN]; \
+ PortalHashEnt *hentry; \
\
- MemSet(key, 0, MAX_PORTALNAME_LEN); \
- StrNCpy(key, NAME, MAX_PORTALNAME_LEN); \
- hentry = (PortalHashEnt*)hash_search(PortalHashTable, \
- key, HASH_FIND, NULL); \
+ hentry = (PortalHashEnt *) hash_search(PortalHashTable, \
+ (NAME), HASH_FIND, NULL); \
if (hentry) \
PORTAL = hentry->portal; \
else \
#define PortalHashTableInsert(PORTAL, NAME) \
do { \
- PortalHashEnt *hentry; bool found; char key[MAX_PORTALNAME_LEN]; \
+ PortalHashEnt *hentry; bool found; \
\
- MemSet(key, 0, MAX_PORTALNAME_LEN); \
- StrNCpy(key, NAME, MAX_PORTALNAME_LEN); \
- hentry = (PortalHashEnt*)hash_search(PortalHashTable, \
- key, HASH_ENTER, &found); \
- if (hentry == NULL) \
- ereport(ERROR, \
- (errcode(ERRCODE_OUT_OF_MEMORY), \
- errmsg("out of memory"))); \
+ hentry = (PortalHashEnt *) hash_search(PortalHashTable, \
+ (NAME), HASH_ENTER, &found); \
if (found) \
elog(ERROR, "duplicate portal name"); \
hentry->portal = PORTAL; \
#define PortalHashTableDelete(PORTAL) \
do { \
- PortalHashEnt *hentry; char key[MAX_PORTALNAME_LEN]; \
+ PortalHashEnt *hentry; \
\
- MemSet(key, 0, MAX_PORTALNAME_LEN); \
- StrNCpy(key, PORTAL->name, MAX_PORTALNAME_LEN); \
- hentry = (PortalHashEnt*)hash_search(PortalHashTable, \
- key, HASH_REMOVE, NULL); \
+ hentry = (PortalHashEnt *) hash_search(PortalHashTable, \
+ PORTAL->name, HASH_REMOVE, NULL); \
if (hentry == NULL) \
elog(WARNING, "trying to delete portal name that does not exist"); \
} while(0)
return portal;
}
+/*
+ * PortalListGetPrimaryStmt
+ * Get the "primary" stmt within a portal, ie, the one marked canSetTag.
+ *
+ * Returns NULL if no such stmt. If multiple PlannedStmt structs within the
+ * portal are marked canSetTag, returns the first one. Neither of these
+ * cases should occur in present usages of this function.
+ *
+ * Copes if given a list of Querys --- can't happen in a portal, but this
+ * code also supports plancache.c, which needs both cases.
+ *
+ * Note: the reason this is just handed a List is so that plancache.c
+ * can share the code. For use with a portal, use PortalGetPrimaryStmt
+ * rather than calling this directly.
+ */
+Node *
+PortalListGetPrimaryStmt(List *stmts)
+{
+ ListCell *lc;
+
+ foreach(lc, stmts)
+ {
+ Node *stmt = (Node *) lfirst(lc);
+
+ if (IsA(stmt, PlannedStmt))
+ {
+ if (((PlannedStmt *) stmt)->canSetTag)
+ return stmt;
+ }
+ else if (IsA(stmt, Query))
+ {
+ if (((Query *) stmt)->canSetTag)
+ return stmt;
+ }
+ else
+ {
+ /* Utility stmts are assumed canSetTag if they're the only stmt */
+ if (list_length(stmts) == 1)
+ return stmt;
+ }
+ }
+ return NULL;
+}
+
/*
* CreatePortal
* Returns a new portal given a name.
"Portal");
/* initialize portal fields that don't start off zero */
+ portal->status = PORTAL_NEW;
portal->cleanup = PortalCleanup;
portal->createSubid = GetCurrentSubTransactionId();
portal->strategy = PORTAL_MULTI_QUERY;
portal->cursorOptions = CURSOR_OPT_NO_SCROLL;
portal->atStart = true;
portal->atEnd = true; /* disallow fetches until query is set */
+ portal->visible = true;
+ portal->creation_time = GetCurrentStatementStartTimestamp();
/* put portal in table (sets portal->name) */
PortalHashTableInsert(portal, name);
*
* Notes: commandTag shall be NULL if and only if the original query string
* (before rewriting) was an empty string. Also, the passed commandTag must
- * be a pointer to a constant string, since it is not copied. The caller is
- * responsible for ensuring that the passed sourceText (if any), parse and
- * plan trees have adequate lifetime. Also, queryContext must accurately
- * describe the location of the parse and plan trees.
+ * be a pointer to a constant string, since it is not copied. However,
+ * prepStmtName and sourceText, if provided, are copied into the portal's
+ * heap context for safekeeping.
+ *
+ * If cplan is provided, then it is a cached plan containing the stmts,
+ * and the caller must have done RevalidateCachedPlan(), causing a refcount
+ * increment. The refcount will be released when the portal is destroyed.
+ *
+ * If cplan is NULL, then it is the caller's responsibility to ensure that
+ * the passed plan trees have adequate lifetime. Typically this is done by
+ * copying them into the portal's heap context.
*/
void
PortalDefineQuery(Portal portal,
+ const char *prepStmtName,
const char *sourceText,
const char *commandTag,
- List *parseTrees,
- List *planTrees,
- MemoryContext queryContext)
+ List *stmts,
+ CachedPlan *cplan)
{
AssertArg(PortalIsValid(portal));
- AssertState(portal->queryContext == NULL); /* else defined already */
+ AssertState(portal->status == PORTAL_NEW);
- Assert(list_length(parseTrees) == list_length(planTrees));
+ Assert(commandTag != NULL || stmts == NIL);
- Assert(commandTag != NULL || parseTrees == NIL);
-
- portal->sourceText = sourceText;
+ portal->prepStmtName = prepStmtName ?
+ MemoryContextStrdup(PortalGetHeapMemory(portal), prepStmtName) : NULL;
+ portal->sourceText = sourceText ?
+ MemoryContextStrdup(PortalGetHeapMemory(portal), sourceText) : NULL;
portal->commandTag = commandTag;
- portal->parseTrees = parseTrees;
- portal->planTrees = planTrees;
- portal->queryContext = queryContext;
+ portal->stmts = stmts;
+ portal->cplan = cplan;
+ portal->status = PORTAL_DEFINED;
+}
+
+/*
+ * PortalReleaseCachedPlan
+ * Release a portal's reference to its cached plan, if any.
+ */
+static void
+PortalReleaseCachedPlan(Portal portal)
+{
+ if (portal->cplan)
+ {
+ ReleaseCachedPlan(portal->cplan, false);
+ portal->cplan = NULL;
+ }
}
/*
Assert(portal->holdStore == NULL);
/*
- * Create the memory context that is used for storage of the tuple
- * set. Note this is NOT a child of the portal's heap memory.
+ * Create the memory context that is used for storage of the tuple set.
+ * Note this is NOT a child of the portal's heap memory.
*/
portal->holdContext =
AllocSetContextCreate(PortalMemory,
elog(ERROR, "cannot drop active portal");
/*
- * Remove portal from hash table. Because we do this first, we will
- * not come back to try to remove the portal again if there's any
- * error in the subsequent steps. Better to leak a little memory than
- * to get into an infinite error-recovery loop.
+ * Remove portal from hash table. Because we do this first, we will not
+ * come back to try to remove the portal again if there's any error in the
+ * subsequent steps. Better to leak a little memory than to get into an
+ * infinite error-recovery loop.
*/
PortalHashTableDelete(portal);
if (PointerIsValid(portal->cleanup))
(*portal->cleanup) (portal);
+ /* drop cached plan reference, if any */
+ if (portal->cplan)
+ PortalReleaseCachedPlan(portal);
+
/*
- * Release any resources still attached to the portal. There are
- * several cases being covered here:
+ * Release any resources still attached to the portal. There are several
+ * cases being covered here:
*
* Top transaction commit (indicated by isTopCommit): normally we should
* do nothing here and let the regular end-of-transaction resource
- * releasing mechanism handle these resources too. However, if we
- * have a FAILED portal (eg, a cursor that got an error), we'd better
- * clean up its resources to avoid resource-leakage warning messages.
+ * releasing mechanism handle these resources too. However, if we have a
+ * FAILED portal (eg, a cursor that got an error), we'd better clean up
+ * its resources to avoid resource-leakage warning messages.
*
* Sub transaction commit: never comes here at all, since we don't kill
* any portals in AtSubCommit_Portals().
* cleaned up in transaction abort.
*
* Ordinary portal drop: must release resources. However, if the portal
- * is not FAILED then we do not release its locks. The locks become
- * the responsibility of the transaction's ResourceOwner (since it is
- * the parent of the portal's owner) and will be released when the
- * transaction eventually ends.
+ * is not FAILED then we do not release its locks. The locks become the
+ * responsibility of the transaction's ResourceOwner (since it is the
+ * parent of the portal's owner) and will be released when the transaction
+ * eventually ends.
*/
if (portal->resowner &&
(!isTopCommit || portal->status == PORTAL_FAILED))
}
/*
- * DropDependentPortals
- * Drop any portals using the specified context as queryContext.
+ * Delete all declared cursors.
*
- * This is normally used to make sure we can safely drop a prepared statement.
+ * Used by commands: CLOSE ALL, RESET SESSION
*/
void
-DropDependentPortals(MemoryContext queryContext)
+PortalHashTableDeleteAll(void)
{
HASH_SEQ_STATUS status;
PortalHashEnt *hentry;
- hash_seq_init(&status, PortalHashTable);
+ if (PortalHashTable == NULL)
+ return;
- while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL)
+ hash_seq_init(&status, PortalHashTable);
+ while ((hentry = hash_seq_search(&status)) != NULL)
{
- Portal portal = hentry->portal;
-
- if (portal->queryContext == queryContext)
+ Portal portal = hentry->portal;
+ if (portal->status != PORTAL_ACTIVE)
PortalDrop(portal, false);
}
}
bool
CommitHoldablePortals(void)
{
- bool result = false;
+ bool result = false;
HASH_SEQ_STATUS status;
PortalHashEnt *hentry;
portal->status == PORTAL_READY)
{
/*
- * We are exiting the transaction that created a holdable
- * cursor. Instead of dropping the portal, prepare it for
- * access by later transactions.
+ * We are exiting the transaction that created a holdable cursor.
+ * Instead of dropping the portal, prepare it for access by later
+ * transactions.
*
* Note that PersistHoldablePortal() must release all resources
- * used by the portal that are local to the creating
- * transaction.
+ * used by the portal that are local to the creating transaction.
*/
PortalCreateHoldStore(portal);
PersistHoldablePortal(portal);
+ /* drop cached plan reference, if any */
+ if (portal->cplan)
+ PortalReleaseCachedPlan(portal);
+
/*
- * Any resources belonging to the portal will be released in
- * the upcoming transaction-wide cleanup; the portal will no
- * longer have its own resources.
+ * Any resources belonging to the portal will be released in the
+ * upcoming transaction-wide cleanup; the portal will no longer
+ * have its own resources.
*/
portal->resowner = NULL;
/*
- * Having successfully exported the holdable cursor, mark it
- * as not belonging to this transaction.
+ * Having successfully exported the holdable cursor, mark it as
+ * not belonging to this transaction.
*/
portal->createSubid = InvalidSubTransactionId;
return result;
}
+/*
+ * Pre-prepare processing for portals.
+ *
+ * Currently we refuse PREPARE if the transaction created any holdable
+ * cursors, since it's quite unclear what to do with one. However, this
+ * has the same API as CommitHoldablePortals and is invoked in the same
+ * way by xact.c, so that we can easily do something reasonable if anyone
+ * comes up with something reasonable to do.
+ *
+ * Returns TRUE if any holdable cursors were processed, FALSE if not.
+ */
+bool
+PrepareHoldablePortals(void)
+{
+ bool result = false;
+ HASH_SEQ_STATUS status;
+ PortalHashEnt *hentry;
+
+ hash_seq_init(&status, PortalHashTable);
+
+ while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL)
+ {
+ Portal portal = hentry->portal;
+
+ /* Is it a holdable portal created in the current xact? */
+ if ((portal->cursorOptions & CURSOR_OPT_HOLD) &&
+ portal->createSubid != InvalidSubTransactionId &&
+ portal->status == PORTAL_READY)
+ {
+ /*
+ * We are exiting the transaction that created a holdable cursor.
+ * Can't do PREPARE.
+ */
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot PREPARE a transaction that has created a cursor WITH HOLD")));
+ }
+ }
+
+ return result;
+}
+
/*
* Pre-commit processing for portals.
*
Portal portal = hentry->portal;
/*
- * Do not touch active portals --- this can only happen in the
- * case of a multi-transaction utility command, such as VACUUM.
+ * Do not touch active portals --- this can only happen in the case of
+ * a multi-transaction utility command, such as VACUUM.
*
* Note however that any resource owner attached to such a portal is
* still going to go away, so don't leave a dangling pointer.
* Abort processing for portals.
*
* At this point we reset "active" status and run the cleanup hook if
- * present, but we can't release memory until the cleanup call.
+ * present, but we can't release the portal's memory until the cleanup call.
*
* The reason we need to reset active is so that we can replace the unnamed
* portal, else we'll fail to execute ROLLBACK when it arrives.
portal->status = PORTAL_FAILED;
/*
- * Do nothing else to cursors held over from a previous
- * transaction.
+ * Do nothing else to cursors held over from a previous transaction.
*/
if (portal->createSubid == InvalidSubTransactionId)
continue;
portal->cleanup = NULL;
}
+ /* drop cached plan reference, if any */
+ if (portal->cplan)
+ PortalReleaseCachedPlan(portal);
+
/*
* Any resources belonging to the portal will be released in the
- * upcoming transaction-wide cleanup; they will be gone before we
- * run PortalDrop.
+ * upcoming transaction-wide cleanup; they will be gone before we run
+ * PortalDrop.
*/
portal->resowner = NULL;
+
+ /*
+ * Although we can't delete the portal data structure proper, we can
+ * release any memory in subsidiary contexts, such as executor state.
+ * The cleanup hook was the last thing that might have needed data
+ * there.
+ */
+ MemoryContextDeleteChildren(PortalGetHeapMemory(portal));
}
}
continue;
/*
- * Force any active portals of my own transaction into FAILED
- * state. This is mostly to ensure that a portal running a FETCH
- * will go FAILED if the underlying cursor fails. (Note we do NOT
- * want to do this to upper-level portals, since they may be able
- * to continue.)
+ * Force any active portals of my own transaction into FAILED state.
+ * This is mostly to ensure that a portal running a FETCH will go
+ * FAILED if the underlying cursor fails. (Note we do NOT want to do
+ * this to upper-level portals, since they may be able to continue.)
*
* This is only needed to dodge the sanity check in PortalDrop.
*/
*
* Currently, we can't actually support that because the portal's
* query might refer to objects created or changed in the failed
- * subtransaction, leading to crashes if execution is resumed.
- * So, even READY portals are deleted. It would be nice to detect
- * whether the query actually depends on any such object, instead.
+ * subtransaction, leading to crashes if execution is resumed. So,
+ * even READY portals are deleted. It would be nice to detect whether
+ * the query actually depends on any such object, instead.
*/
#ifdef NOT_USED
if (portal->status == PORTAL_READY)
portal->cleanup = NULL;
}
+ /* drop cached plan reference, if any */
+ if (portal->cplan)
+ PortalReleaseCachedPlan(portal);
+
/*
- * Any resources belonging to the portal will be released in
- * the upcoming transaction-wide cleanup; they will be gone
- * before we run PortalDrop.
+ * Any resources belonging to the portal will be released in the
+ * upcoming transaction-wide cleanup; they will be gone before we
+ * run PortalDrop.
*/
portal->resowner = NULL;
+
+ /*
+ * Although we can't delete the portal data structure proper, we
+ * can release any memory in subsidiary contexts, such as executor
+ * state. The cleanup hook was the last thing that might have
+ * needed data there.
+ */
+ MemoryContextDeleteChildren(PortalGetHeapMemory(portal));
}
}
}
PortalDrop(portal, false);
}
}
+
+/* Find all available cursors */
+Datum
+pg_cursor(PG_FUNCTION_ARGS)
+{
+ FuncCallContext *funcctx;
+ HASH_SEQ_STATUS *hash_seq;
+ PortalHashEnt *hentry;
+
+ /* stuff done only on the first call of the function */
+ if (SRF_IS_FIRSTCALL())
+ {
+ MemoryContext oldcontext;
+ TupleDesc tupdesc;
+
+ /* create a function context for cross-call persistence */
+ funcctx = SRF_FIRSTCALL_INIT();
+
+ /*
+ * switch to memory context appropriate for multiple function calls
+ */
+ oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+
+ if (PortalHashTable)
+ {
+ hash_seq = (HASH_SEQ_STATUS *) palloc(sizeof(HASH_SEQ_STATUS));
+ hash_seq_init(hash_seq, PortalHashTable);
+ funcctx->user_fctx = (void *) hash_seq;
+ }
+ else
+ funcctx->user_fctx = NULL;
+
+ /*
+ * build tupdesc for result tuples. This must match the definition of
+ * the pg_cursors view in system_views.sql
+ */
+ tupdesc = CreateTemplateTupleDesc(6, false);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 1, "name",
+ TEXTOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 2, "statement",
+ TEXTOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 3, "is_holdable",
+ BOOLOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 4, "is_binary",
+ BOOLOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 5, "is_scrollable",
+ BOOLOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 6, "creation_time",
+ TIMESTAMPTZOID, -1, 0);
+
+ funcctx->tuple_desc = BlessTupleDesc(tupdesc);
+ MemoryContextSwitchTo(oldcontext);
+ }
+
+ /* stuff done on every call of the function */
+ funcctx = SRF_PERCALL_SETUP();
+ hash_seq = (HASH_SEQ_STATUS *) funcctx->user_fctx;
+
+ /* if the hash table is uninitialized, we're done */
+ if (hash_seq == NULL)
+ SRF_RETURN_DONE(funcctx);
+
+ /* loop until we find a visible portal or hit the end of the list */
+ while ((hentry = hash_seq_search(hash_seq)) != NULL)
+ {
+ if (hentry->portal->visible)
+ break;
+ }
+
+ if (hentry)
+ {
+ Portal portal;
+ Datum result;
+ HeapTuple tuple;
+ Datum values[6];
+ bool nulls[6];
+
+ portal = hentry->portal;
+ MemSet(nulls, 0, sizeof(nulls));
+
+ values[0] = DirectFunctionCall1(textin, CStringGetDatum(portal->name));
+ if (!portal->sourceText)
+ nulls[1] = true;
+ else
+ values[1] = DirectFunctionCall1(textin,
+ CStringGetDatum(portal->sourceText));
+ values[2] = BoolGetDatum(portal->cursorOptions & CURSOR_OPT_HOLD);
+ values[3] = BoolGetDatum(portal->cursorOptions & CURSOR_OPT_BINARY);
+ values[4] = BoolGetDatum(portal->cursorOptions & CURSOR_OPT_SCROLL);
+ values[5] = TimestampTzGetDatum(portal->creation_time);
+
+ tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
+ result = HeapTupleGetDatum(tuple);
+ SRF_RETURN_NEXT(funcctx, result);
+ }
+
+ SRF_RETURN_DONE(funcctx);
+}
projects / postgresql / blobdiff