/*------------------------------------------------------------------------- * * portalmem.c * backend portal memory management * * Portals are objects representing the execution state of a query. * This module provides memory management services for portals, but it * doesn't actually run the executor for them. * * * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION * src/backend/utils/mmgr/portalmem.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/xact.h" #include "catalog/pg_type.h" #include "commands/portalcmds.h" #include "miscadmin.h" #include "utils/builtins.h" #include "utils/memutils.h" #include "utils/timestamp.h" /* * Estimate of the maximum number of open portals a user would have, * used in initially sizing the PortalHashTable in EnablePortalManager(). * Since the hash table can expand, there's no need to make this overly * generous, and keeping it small avoids unnecessary overhead in the * hash_seq_search() calls executed during transaction end. */ #define PORTALS_PER_USER 16 /* ---------------- * Global state * ---------------- */ #define MAX_PORTALNAME_LEN NAMEDATALEN typedef struct portalhashent { char portalname[MAX_PORTALNAME_LEN]; Portal portal; } PortalHashEnt; static HTAB *PortalHashTable = NULL; #define PortalHashTableLookup(NAME, PORTAL) \ do { \ PortalHashEnt *hentry; \ \ hentry = (PortalHashEnt *) hash_search(PortalHashTable, \ (NAME), HASH_FIND, NULL); \ if (hentry) \ PORTAL = hentry->portal; \ else \ PORTAL = NULL; \ } while(0) #define PortalHashTableInsert(PORTAL, NAME) \ do { \ PortalHashEnt *hentry; bool found; \ \ hentry = (PortalHashEnt *) hash_search(PortalHashTable, \ (NAME), HASH_ENTER, &found); \ if (found) \ elog(ERROR, "duplicate portal name"); \ hentry->portal = PORTAL; \ /* To avoid duplicate storage, make PORTAL->name point to htab entry */ \ PORTAL->name = hentry->portalname; \ } while(0) #define PortalHashTableDelete(PORTAL) \ do { \ PortalHashEnt *hentry; \ \ 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) static MemoryContext PortalMemory = NULL; /* ---------------------------------------------------------------- * public portal interface functions * ---------------------------------------------------------------- */ /* * EnablePortalManager * Enables the portal management module at backend startup. */ void EnablePortalManager(void) { HASHCTL ctl; Assert(PortalMemory == NULL); PortalMemory = AllocSetContextCreate(TopMemoryContext, "PortalMemory", ALLOCSET_DEFAULT_MINSIZE, ALLOCSET_DEFAULT_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE); ctl.keysize = MAX_PORTALNAME_LEN; ctl.entrysize = sizeof(PortalHashEnt); /* * use PORTALS_PER_USER as a guess of how many hash table entries to * create, initially */ PortalHashTable = hash_create("Portal hash", PORTALS_PER_USER, &ctl, HASH_ELEM); } /* * GetPortalByName * Returns a portal given a portal name, or NULL if name not found. */ Portal GetPortalByName(const char *name) { Portal portal; if (PointerIsValid(name)) PortalHashTableLookup(name, portal); else portal = NULL; 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. * * allowDup: if true, automatically drop any pre-existing portal of the * same name (if false, an error is raised). * * dupSilent: if true, don't even emit a WARNING. */ Portal CreatePortal(const char *name, bool allowDup, bool dupSilent) { Portal portal; AssertArg(PointerIsValid(name)); portal = GetPortalByName(name); if (PortalIsValid(portal)) { if (!allowDup) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_CURSOR), errmsg("cursor \"%s\" already exists", name))); if (!dupSilent) ereport(WARNING, (errcode(ERRCODE_DUPLICATE_CURSOR), errmsg("closing existing cursor \"%s\"", name))); PortalDrop(portal, false); } /* make new portal structure */ portal = (Portal) MemoryContextAllocZero(PortalMemory, sizeof *portal); /* initialize portal heap context; typically it won't store much */ portal->heap = AllocSetContextCreate(PortalMemory, "PortalHeapMemory", ALLOCSET_SMALL_MINSIZE, ALLOCSET_SMALL_INITSIZE, ALLOCSET_SMALL_MAXSIZE); /* create a resource owner for the portal */ portal->resowner = ResourceOwnerCreate(CurTransactionResourceOwner, "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); return portal; } /* * CreateNewPortal * Create a new portal, assigning it a random nonconflicting name. */ Portal CreateNewPortal(void) { static unsigned int unnamed_portal_count = 0; char portalname[MAX_PORTALNAME_LEN]; /* Select a nonconflicting name */ for (;;) { unnamed_portal_count++; sprintf(portalname, "", unnamed_portal_count); if (GetPortalByName(portalname) == NULL) break; } return CreatePortal(portalname, false, false); } /* * PortalDefineQuery * A simple subroutine to establish a portal's query. * * Notes: as of PG 8.4, caller MUST supply a sourceText string; it is not * allowed anymore to pass NULL. (If you really don't have source text, * you can pass a constant string, perhaps "(query not available)".) * * 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. * * If cplan is provided, then it is a cached plan containing the stmts, and * the caller must have done GetCachedPlan(), 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. * * The caller is also responsible for ensuring that the passed prepStmtName * (if not NULL) and sourceText have adequate lifetime. * * NB: this function mustn't do much beyond storing the passed values; in * particular don't do anything that risks elog(ERROR). If that were to * happen here before storing the cplan reference, we'd leak the plancache * refcount that the caller is trying to hand off to us. */ void PortalDefineQuery(Portal portal, const char *prepStmtName, const char *sourceText, const char *commandTag, List *stmts, CachedPlan *cplan) { AssertArg(PortalIsValid(portal)); AssertState(portal->status == PORTAL_NEW); AssertArg(sourceText != NULL); AssertArg(commandTag != NULL || stmts == NIL); portal->prepStmtName = prepStmtName; portal->sourceText = sourceText; portal->commandTag = commandTag; 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; /* * We must also clear portal->stmts which is now a dangling reference * to the cached plan's plan list. This protects any code that might * try to examine the Portal later. */ portal->stmts = NIL; } } /* * PortalCreateHoldStore * Create the tuplestore for a portal. */ void PortalCreateHoldStore(Portal portal) { MemoryContext oldcxt; Assert(portal->holdContext == 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. */ portal->holdContext = AllocSetContextCreate(PortalMemory, "PortalHoldContext", ALLOCSET_DEFAULT_MINSIZE, ALLOCSET_DEFAULT_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE); /* * Create the tuple store, selecting cross-transaction temp files, and * enabling random access only if cursor requires scrolling. * * XXX: Should maintenance_work_mem be used for the portal size? */ oldcxt = MemoryContextSwitchTo(portal->holdContext); portal->holdStore = tuplestore_begin_heap(portal->cursorOptions & CURSOR_OPT_SCROLL, true, work_mem); MemoryContextSwitchTo(oldcxt); } /* * PinPortal * Protect a portal from dropping. * * A pinned portal is still unpinned and dropped at transaction or * subtransaction abort. */ void PinPortal(Portal portal) { if (portal->portalPinned) elog(ERROR, "portal already pinned"); portal->portalPinned = true; } void UnpinPortal(Portal portal) { if (!portal->portalPinned) elog(ERROR, "portal not pinned"); portal->portalPinned = false; } /* * MarkPortalDone * Transition a portal from ACTIVE to DONE state. * * NOTE: never set portal->status = PORTAL_DONE directly; call this instead. */ void MarkPortalDone(Portal portal) { /* Perform the state transition */ Assert(portal->status == PORTAL_ACTIVE); portal->status = PORTAL_DONE; /* * Allow portalcmds.c to clean up the state it knows about. We might as * well do that now, since the portal can't be executed any more. * * In some cases involving execution of a ROLLBACK command in an already * aborted transaction, this prevents an assertion failure caused by * reaching AtCleanup_Portals with the cleanup hook still unexecuted. */ if (PointerIsValid(portal->cleanup)) { (*portal->cleanup) (portal); portal->cleanup = NULL; } } /* * MarkPortalFailed * Transition a portal into FAILED state. * * NOTE: never set portal->status = PORTAL_FAILED directly; call this instead. */ void MarkPortalFailed(Portal portal) { /* Perform the state transition */ Assert(portal->status != PORTAL_DONE); portal->status = PORTAL_FAILED; /* * Allow portalcmds.c to clean up the state it knows about. We might as * well do that now, since the portal can't be executed any more. * * In some cases involving cleanup of an already aborted transaction, this * prevents an assertion failure caused by reaching AtCleanup_Portals with * the cleanup hook still unexecuted. */ if (PointerIsValid(portal->cleanup)) { (*portal->cleanup) (portal); portal->cleanup = NULL; } } /* * PortalDrop * Destroy the portal. */ void PortalDrop(Portal portal, bool isTopCommit) { AssertArg(PortalIsValid(portal)); /* * Don't allow dropping a pinned portal, it's still needed by whoever * pinned it. Not sure if the PORTAL_ACTIVE case can validly happen or * not... */ if (portal->portalPinned || portal->status == PORTAL_ACTIVE) ereport(ERROR, (errcode(ERRCODE_INVALID_CURSOR_STATE), errmsg("cannot drop active portal \"%s\"", portal->name))); /* * Allow portalcmds.c to clean up the state it knows about, in particular * shutting down the executor if still active. This step potentially runs * user-defined code so failure has to be expected. It's the cleanup * hook's responsibility to not try to do that more than once, in the case * that failure occurs and then we come back to drop the portal again * during transaction abort. * * Note: in most paths of control, this will have been done already in * MarkPortalDone or MarkPortalFailed. We're just making sure. */ if (PointerIsValid(portal->cleanup)) { (*portal->cleanup) (portal); portal->cleanup = NULL; } /* * Remove portal from hash table. Because we do this here, 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); /* drop cached plan reference, if any */ PortalReleaseCachedPlan(portal); /* * 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. * * Sub transaction commit: never comes here at all, since we don't kill * any portals in AtSubCommit_Portals(). * * Main or sub transaction abort: we will do nothing here because * portal->resowner was already set NULL; the resources were already * 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. */ if (portal->resowner && (!isTopCommit || portal->status == PORTAL_FAILED)) { bool isCommit = (portal->status != PORTAL_FAILED); ResourceOwnerRelease(portal->resowner, RESOURCE_RELEASE_BEFORE_LOCKS, isCommit, false); ResourceOwnerRelease(portal->resowner, RESOURCE_RELEASE_LOCKS, isCommit, false); ResourceOwnerRelease(portal->resowner, RESOURCE_RELEASE_AFTER_LOCKS, isCommit, false); ResourceOwnerDelete(portal->resowner); } portal->resowner = NULL; /* * Delete tuplestore if present. We should do this even under error * conditions; since the tuplestore would have been using cross- * transaction storage, its temp files need to be explicitly deleted. */ if (portal->holdStore) { MemoryContext oldcontext; oldcontext = MemoryContextSwitchTo(portal->holdContext); tuplestore_end(portal->holdStore); MemoryContextSwitchTo(oldcontext); portal->holdStore = NULL; } /* delete tuplestore storage, if any */ if (portal->holdContext) MemoryContextDelete(portal->holdContext); /* release subsidiary storage */ MemoryContextDelete(PortalGetHeapMemory(portal)); /* release portal struct (it's in PortalMemory) */ pfree(portal); } /* * Delete all declared cursors. * * Used by commands: CLOSE ALL, DISCARD ALL */ void PortalHashTableDeleteAll(void) { HASH_SEQ_STATUS status; PortalHashEnt *hentry; if (PortalHashTable == NULL) return; hash_seq_init(&status, PortalHashTable); while ((hentry = hash_seq_search(&status)) != NULL) { Portal portal = hentry->portal; /* Can't close the active portal (the one running the command) */ if (portal->status == PORTAL_ACTIVE) continue; PortalDrop(portal, false); /* Restart the iteration in case that led to other drops */ hash_seq_term(&status); hash_seq_init(&status, PortalHashTable); } } /* * Pre-commit processing for portals. * * Holdable cursors created in this transaction need to be converted to * materialized form, since we are going to close down the executor and * release locks. Non-holdable portals created in this transaction are * simply removed. Portals remaining from prior transactions should be * left untouched. * * Returns TRUE if any portals changed state (possibly causing user-defined * code to be run), FALSE if not. */ bool PreCommit_Portals(bool isPrepare) { 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; /* * There should be no pinned portals anymore. Complain if someone * leaked one. */ if (portal->portalPinned) elog(ERROR, "cannot commit while a portal is pinned"); /* * 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. */ if (portal->status == PORTAL_ACTIVE) { portal->resowner = NULL; continue; } /* 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. * Instead of dropping the portal, prepare it for access by later * transactions. * * However, if this is PREPARE TRANSACTION rather than COMMIT, * refuse PREPARE, because the semantics seem pretty unclear. */ if (isPrepare) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot PREPARE a transaction that has created a cursor WITH HOLD"))); /* * Note that PersistHoldablePortal() must release all resources * used by the portal that are local to the creating transaction. */ PortalCreateHoldStore(portal); PersistHoldablePortal(portal); /* drop cached plan reference, if any */ 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. */ portal->resowner = NULL; /* * Having successfully exported the holdable cursor, mark it as * not belonging to this transaction. */ portal->createSubid = InvalidSubTransactionId; /* Report we changed state */ result = true; } else if (portal->createSubid == InvalidSubTransactionId) { /* * Do nothing to cursors held over from a previous transaction * (including ones we just froze in a previous cycle of this loop) */ continue; } else { /* Zap all non-holdable portals */ PortalDrop(portal, true); /* Report we changed state */ result = true; } /* * After either freezing or dropping a portal, we have to restart the * iteration, because we could have invoked user-defined code that * caused a drop of the next portal in the hash chain. */ hash_seq_term(&status); hash_seq_init(&status, PortalHashTable); } return result; } /* * Abort processing for portals. * * At this point we reset "active" status and run the cleanup hook if * 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. */ void AtAbort_Portals(void) { HASH_SEQ_STATUS status; PortalHashEnt *hentry; hash_seq_init(&status, PortalHashTable); while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL) { Portal portal = hentry->portal; /* Any portal that was actually running has to be considered broken */ if (portal->status == PORTAL_ACTIVE) MarkPortalFailed(portal); /* * Do nothing else to cursors held over from a previous transaction. */ if (portal->createSubid == InvalidSubTransactionId) continue; /* * If it was created in the current transaction, we can't do normal * shutdown on a READY portal either; it might refer to objects * created in the failed transaction. See comments in * AtSubAbort_Portals. */ if (portal->status == PORTAL_READY) MarkPortalFailed(portal); /* * Allow portalcmds.c to clean up the state it knows about, if we * haven't already. */ if (PointerIsValid(portal->cleanup)) { (*portal->cleanup) (portal); portal->cleanup = NULL; } /* drop cached plan reference, if any */ 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. */ 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)); } } /* * Post-abort cleanup for portals. * * Delete all portals not held over from prior transactions. */ void AtCleanup_Portals(void) { HASH_SEQ_STATUS status; PortalHashEnt *hentry; hash_seq_init(&status, PortalHashTable); while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL) { Portal portal = hentry->portal; /* Do nothing to cursors held over from a previous transaction */ if (portal->createSubid == InvalidSubTransactionId) { Assert(portal->status != PORTAL_ACTIVE); Assert(portal->resowner == NULL); continue; } /* * If a portal is still pinned, forcibly unpin it. PortalDrop will not * let us drop the portal otherwise. Whoever pinned the portal was * interrupted by the abort too and won't try to use it anymore. */ if (portal->portalPinned) portal->portalPinned = false; /* We had better not be calling any user-defined code here */ Assert(portal->cleanup == NULL); /* Zap it. */ PortalDrop(portal, false); } } /* * Pre-subcommit processing for portals. * * Reassign the portals created in the current subtransaction to the parent * subtransaction. */ void AtSubCommit_Portals(SubTransactionId mySubid, SubTransactionId parentSubid, ResourceOwner parentXactOwner) { HASH_SEQ_STATUS status; PortalHashEnt *hentry; hash_seq_init(&status, PortalHashTable); while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL) { Portal portal = hentry->portal; if (portal->createSubid == mySubid) { portal->createSubid = parentSubid; if (portal->resowner) ResourceOwnerNewParent(portal->resowner, parentXactOwner); } } } /* * Subtransaction abort handling for portals. * * Deactivate portals created during the failed subtransaction. * Note that per AtSubCommit_Portals, this will catch portals created * in descendants of the subtransaction too. * * We don't destroy any portals here; that's done in AtSubCleanup_Portals. */ void AtSubAbort_Portals(SubTransactionId mySubid, SubTransactionId parentSubid, ResourceOwner parentXactOwner) { HASH_SEQ_STATUS status; PortalHashEnt *hentry; hash_seq_init(&status, PortalHashTable); while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL) { Portal portal = hentry->portal; if (portal->createSubid != mySubid) continue; /* * Force any live portals of my own subtransaction into FAILED state. * We have to do this because they might refer to objects created or * changed in the failed subtransaction, leading to crashes if * execution is resumed, or even if we just try to run ExecutorEnd. * (Note we do NOT do this to upper-level portals, since they cannot * have such references and hence may be able to continue.) */ if (portal->status == PORTAL_READY || portal->status == PORTAL_ACTIVE) MarkPortalFailed(portal); /* * Allow portalcmds.c to clean up the state it knows about, if we * haven't already. */ if (PointerIsValid(portal->cleanup)) { (*portal->cleanup) (portal); portal->cleanup = NULL; } /* drop cached plan reference, if any */ 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. */ 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)); } } /* * Post-subabort cleanup for portals. * * Drop all portals created in the failed subtransaction (but note that * we will not drop any that were reassigned to the parent above). */ void AtSubCleanup_Portals(SubTransactionId mySubid) { HASH_SEQ_STATUS status; PortalHashEnt *hentry; hash_seq_init(&status, PortalHashTable); while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL) { Portal portal = hentry->portal; if (portal->createSubid != mySubid) continue; /* * If a portal is still pinned, forcibly unpin it. PortalDrop will not * let us drop the portal otherwise. Whoever pinned the portal was * interrupted by the abort too and won't try to use it anymore. */ if (portal->portalPinned) portal->portalPinned = false; /* We had better not be calling any user-defined code here */ Assert(portal->cleanup == NULL); /* Zap it. */ PortalDrop(portal, false); } } /* Find all available cursors */ Datum pg_cursor(PG_FUNCTION_ARGS) { ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; TupleDesc tupdesc; Tuplestorestate *tupstore; MemoryContext per_query_ctx; MemoryContext oldcontext; HASH_SEQ_STATUS hash_seq; PortalHashEnt *hentry; /* check to see if caller supports us returning a tuplestore */ if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("set-valued function called in context that cannot accept a set"))); if (!(rsinfo->allowedModes & SFRM_Materialize)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("materialize mode required, but it is not " \ "allowed in this context"))); /* need to build tuplestore in query context */ per_query_ctx = rsinfo->econtext->ecxt_per_query_memory; oldcontext = MemoryContextSwitchTo(per_query_ctx); /* * 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); /* * We put all the tuples into a tuplestore in one scan of the hashtable. * This avoids any issue of the hashtable possibly changing between calls. */ tupstore = tuplestore_begin_heap(rsinfo->allowedModes & SFRM_Materialize_Random, false, work_mem); /* generate junk in short-term context */ MemoryContextSwitchTo(oldcontext); hash_seq_init(&hash_seq, PortalHashTable); while ((hentry = hash_seq_search(&hash_seq)) != NULL) { Portal portal = hentry->portal; Datum values[6]; bool nulls[6]; /* report only "visible" entries */ if (!portal->visible) continue; MemSet(nulls, 0, sizeof(nulls)); values[0] = CStringGetTextDatum(portal->name); values[1] = CStringGetTextDatum(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); tuplestore_putvalues(tupstore, tupdesc, values, nulls); } /* clean up and return the tuplestore */ tuplestore_donestoring(tupstore); rsinfo->returnMode = SFRM_Materialize; rsinfo->setResult = tupstore; rsinfo->setDesc = tupdesc; return (Datum) 0; } bool ThereAreNoReadyPortals(void) { HASH_SEQ_STATUS status; PortalHashEnt *hentry; hash_seq_init(&status, PortalHashTable); while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL) { Portal portal = hentry->portal; if (portal->status == PORTAL_READY) return false; } return true; }