diff options
Diffstat (limited to 'src/backend/tcop/pquery.c')
| -rw-r--r-- | src/backend/tcop/pquery.c | 220 |
1 files changed, 107 insertions, 113 deletions
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c index 75eb75f6de7..edf2ba44aeb 100644 --- a/src/backend/tcop/pquery.c +++ b/src/backend/tcop/pquery.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.94 2005/06/22 17:45:46 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.95 2005/10/15 02:49:27 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -72,7 +72,7 @@ CreateQueryDesc(Query *parsetree, qd->parsetree = parsetree; /* parse tree */ qd->plantree = plantree; /* plan */ qd->snapshot = snapshot; /* snapshot */ - qd->crosscheck_snapshot = crosscheck_snapshot; /* RI check snapshot */ + qd->crosscheck_snapshot = crosscheck_snapshot; /* RI check snapshot */ qd->dest = dest; /* output dest */ qd->params = params; /* parameter values passed into query */ qd->doInstrument = doInstrument; /* instrumentation wanted? */ @@ -138,16 +138,16 @@ ProcessQuery(Query *parsetree, * SELECT INTO table (a/k/a CREATE AS ... SELECT). * * Override the normal communication destination; execMain.c - * special-cases this case. (Perhaps would be cleaner to have - * an additional destination type?) + * special-cases this case. (Perhaps would be cleaner to have an + * additional destination type?) */ dest = None_Receiver; } } /* - * Must always set snapshot for plannable queries. Note we assume - * that caller will take care of restoring ActiveSnapshot on exit/error. + * Must always set snapshot for plannable queries. Note we assume that + * caller will take care of restoring ActiveSnapshot on exit/error. */ ActiveSnapshot = CopySnapshot(GetTransactionSnapshot()); @@ -191,7 +191,7 @@ ProcessQuery(Query *parsetree, else lastOid = InvalidOid; snprintf(completionTag, COMPLETION_TAG_BUFSIZE, - "INSERT %u %u", lastOid, queryDesc->estate->es_processed); + "INSERT %u %u", lastOid, queryDesc->estate->es_processed); break; case CMD_UPDATE: snprintf(completionTag, COMPLETION_TAG_BUFSIZE, @@ -270,31 +270,31 @@ FetchPortalTargetList(Portal portal) return ((Query *) linitial(portal->parseTrees))->targetList; if (portal->strategy == PORTAL_UTIL_SELECT) { - Node *utilityStmt; + Node *utilityStmt; utilityStmt = ((Query *) linitial(portal->parseTrees))->utilityStmt; switch (nodeTag(utilityStmt)) { case T_FetchStmt: - { - FetchStmt *substmt = (FetchStmt *) utilityStmt; - Portal subportal; + { + FetchStmt *substmt = (FetchStmt *) utilityStmt; + Portal subportal; - Assert(!substmt->ismove); - subportal = GetPortalByName(substmt->portalname); - Assert(PortalIsValid(subportal)); - return FetchPortalTargetList(subportal); - } + Assert(!substmt->ismove); + subportal = GetPortalByName(substmt->portalname); + Assert(PortalIsValid(subportal)); + return FetchPortalTargetList(subportal); + } case T_ExecuteStmt: - { - ExecuteStmt *substmt = (ExecuteStmt *) utilityStmt; - PreparedStatement *entry; + { + ExecuteStmt *substmt = (ExecuteStmt *) utilityStmt; + PreparedStatement *entry; - Assert(!substmt->into); - entry = FetchPreparedStatement(substmt->name, true); - return FetchPreparedStatementTargetList(entry); - } + Assert(!substmt->into); + entry = FetchPreparedStatement(substmt->name, true); + return FetchPreparedStatementTargetList(entry); + } default: break; @@ -335,8 +335,7 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot) AssertState(portal->status == PORTAL_NEW); /* else extra PortalStart */ /* - * Set up global portal context pointers. (Should we set - * QueryContext?) + * Set up global portal context pointers. (Should we set QueryContext?) */ saveActivePortal = ActivePortal; saveActiveSnapshot = ActiveSnapshot; @@ -345,7 +344,7 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot) PG_TRY(); { ActivePortal = portal; - ActiveSnapshot = NULL; /* will be set later */ + ActiveSnapshot = NULL; /* will be set later */ CurrentResourceOwner = portal->resowner; PortalContext = PortalGetHeapMemory(portal); @@ -367,7 +366,7 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot) case PORTAL_ONE_SELECT: /* - * Must set snapshot before starting executor. Be sure to + * Must set snapshot before starting executor. Be sure to * copy it into the portal's context. */ if (snapshot) @@ -376,11 +375,11 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot) ActiveSnapshot = CopySnapshot(GetTransactionSnapshot()); /* - * Create QueryDesc in portal's context; for the moment, - * set the destination to None. + * Create QueryDesc in portal's context; for the moment, set + * the destination to None. */ queryDesc = CreateQueryDesc((Query *) linitial(portal->parseTrees), - (Plan *) linitial(portal->planTrees), + (Plan *) linitial(portal->planTrees), ActiveSnapshot, InvalidSnapshot, None_Receiver, @@ -388,10 +387,10 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot) false); /* - * We do *not* call AfterTriggerBeginQuery() here. We - * assume that a SELECT cannot queue any triggers. It - * would be messy to support triggers since the execution - * of the portal may be interleaved with other queries. + * We do *not* call AfterTriggerBeginQuery() here. We assume + * that a SELECT cannot queue any triggers. It would be messy + * to support triggers since the execution of the portal may + * be interleaved with other queries. */ /* @@ -421,8 +420,8 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot) case PORTAL_UTIL_SELECT: /* - * We don't set snapshot here, because - * PortalRunUtility will take care of it if needed. + * We don't set snapshot here, because PortalRunUtility will + * take care of it if needed. */ portal->tupDesc = UtilityTupleDescriptor(((Query *) linitial(portal->parseTrees))->utilityStmt); @@ -579,14 +578,14 @@ PortalRun(Portal portal, long count, * * We have to play a special game here to support utility commands like * VACUUM and CLUSTER, which internally start and commit transactions. - * When we are called to execute such a command, CurrentResourceOwner - * will be pointing to the TopTransactionResourceOwner --- which will - * be destroyed and replaced in the course of the internal commit and - * restart. So we need to be prepared to restore it as pointing to - * the exit-time TopTransactionResourceOwner. (Ain't that ugly? This - * idea of internally starting whole new transactions is not good.) - * CurrentMemoryContext has a similar problem, but the other pointers - * we save here will be NULL or pointing to longer-lived objects. + * When we are called to execute such a command, CurrentResourceOwner will + * be pointing to the TopTransactionResourceOwner --- which will be + * destroyed and replaced in the course of the internal commit and + * restart. So we need to be prepared to restore it as pointing to the + * exit-time TopTransactionResourceOwner. (Ain't that ugly? This idea of + * internally starting whole new transactions is not good.) + * CurrentMemoryContext has a similar problem, but the other pointers we + * save here will be NULL or pointing to longer-lived objects. */ saveTopTransactionResourceOwner = TopTransactionResourceOwner; saveTopTransactionContext = TopTransactionContext; @@ -599,7 +598,7 @@ PortalRun(Portal portal, long count, PG_TRY(); { ActivePortal = portal; - ActiveSnapshot = NULL; /* will be set later */ + ActiveSnapshot = NULL; /* will be set later */ CurrentResourceOwner = portal->resowner; PortalContext = PortalGetHeapMemory(portal); QueryContext = portal->queryContext; @@ -618,8 +617,7 @@ PortalRun(Portal portal, long count, portal->status = PORTAL_READY; /* - * Since it's a forward fetch, say DONE iff atEnd is now - * true. + * Since it's a forward fetch, say DONE iff atEnd is now true. */ result = portal->atEnd; break; @@ -658,8 +656,7 @@ PortalRun(Portal portal, long count, portal->status = PORTAL_READY; /* - * Since it's a forward fetch, say DONE iff atEnd is now - * true. + * Since it's a forward fetch, say DONE iff atEnd is now true. */ result = portal->atEnd; break; @@ -750,8 +747,8 @@ PortalRunSelect(Portal portal, uint32 nprocessed; /* - * NB: queryDesc will be NULL if we are fetching from a held cursor or - * a completed utility query; can't use it in that path. + * NB: queryDesc will be NULL if we are fetching from a held cursor or a + * completed utility query; can't use it in that path. */ queryDesc = PortalGetQueryDesc(portal); @@ -768,15 +765,15 @@ PortalRunSelect(Portal portal, queryDesc->dest = dest; /* - * 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, 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.) 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 portal position state depending on - * the number of tuples that were retrieved. + * 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, 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.) 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 portal position state depending on the number of tuples that were + * retrieved. */ if (forward) { @@ -924,9 +921,9 @@ RunFromStore(Portal portal, ScanDirection direction, long count, ExecClearTuple(slot); /* - * check our tuple count.. if we've processed the proper - * number then quit, else loop again and process more tuples. - * Zero count means no limit. + * check our tuple count.. if we've processed the proper number + * then quit, else loop again and process more tuples. Zero count + * means no limit. */ current_tuple_count++; if (count && count == current_tuple_count) @@ -955,19 +952,18 @@ PortalRunUtility(Portal portal, Query *query, (errmsg_internal("ProcessUtility"))); /* - * Set snapshot if utility stmt needs one. Most reliable way to do - * this seems to be to enumerate those that do not need one; this is a - * short list. Transaction control, LOCK, and SET must *not* set a - * snapshot since they need to be executable at the start of a - * serializable transaction without freezing a snapshot. By extension - * we allow SHOW not to set a snapshot. The other stmts listed are - * just efficiency hacks. Beware of listing anything that can modify - * the database --- if, say, it has to update an index with - * expressions that invoke user-defined functions, then it had better - * have a snapshot. + * Set snapshot if utility stmt needs one. Most reliable way to do this + * seems to be to enumerate those that do not need one; this is a short + * list. Transaction control, LOCK, and SET must *not* set a snapshot + * since they need to be executable at the start of a serializable + * transaction without freezing a snapshot. By extension we allow SHOW + * not to set a snapshot. The other stmts listed are just efficiency + * hacks. Beware of listing anything that can modify the database --- if, + * say, it has to update an index with expressions that invoke + * user-defined functions, then it had better have a snapshot. * - * Note we assume that caller will take care of restoring ActiveSnapshot - * on exit/error. + * Note we assume that caller will take care of restoring ActiveSnapshot on + * exit/error. */ if (!(IsA(utilityStmt, TransactionStmt) || IsA(utilityStmt, LockStmt) || @@ -1020,13 +1016,13 @@ PortalRunMulti(Portal portal, /* * If the destination is RemoteExecute, change to None. The reason is - * that the client won't be expecting any tuples, and indeed has no - * way to know what they are, since there is no provision for Describe - * to send a RowDescription message when this portal execution - * strategy is in effect. This presently will only affect SELECT - * commands added to non-SELECT queries by rewrite rules: such - * commands will be executed, but the results will be discarded unless - * you use "simple Query" protocol. + * that the client won't be expecting any tuples, and indeed has no way to + * know what they are, since there is no provision for Describe to send a + * RowDescription message when this portal execution strategy is in + * effect. This presently will only affect SELECT commands added to + * non-SELECT queries by rewrite rules: such commands will be executed, + * but the results will be discarded unless you use "simple Query" + * protocol. */ if (dest->mydest == RemoteExecute) dest = None_Receiver; @@ -1034,8 +1030,8 @@ PortalRunMulti(Portal portal, altdest = None_Receiver; /* - * Loop to handle the individual queries generated from a single - * parsetree by analysis and rewrite. + * Loop to handle the individual queries generated from a single parsetree + * by analysis and rewrite. */ forboth(querylist_item, portal->parseTrees, planlist_item, portal->planTrees) @@ -1087,8 +1083,8 @@ PortalRunMulti(Portal portal, } /* - * Increment command counter between queries, but not after the - * last one. + * Increment command counter between queries, but not after the last + * one. */ if (lnext(planlist_item) != NULL) CommandCounterIncrement(); @@ -1102,12 +1098,12 @@ PortalRunMulti(Portal portal, } /* - * If a command completion tag was supplied, use it. Otherwise use - * the portal's commandTag as the default completion tag. + * If a command completion tag was supplied, use it. Otherwise use the + * portal's commandTag as the default completion tag. * - * Exception: clients will expect INSERT/UPDATE/DELETE tags to have - * counts, so fake something up if necessary. (This could happen if - * the original query was replaced by a DO INSTEAD rule.) + * Exception: clients will expect INSERT/UPDATE/DELETE tags to have counts, + * so fake something up if necessary. (This could happen if the original + * query was replaced by a DO INSTEAD rule.) */ if (completionTag && completionTag[0] == '\0') { @@ -1164,7 +1160,7 @@ PortalRunFetch(Portal portal, PG_TRY(); { ActivePortal = portal; - ActiveSnapshot = NULL; /* will be set later */ + ActiveSnapshot = NULL; /* will be set later */ CurrentResourceOwner = portal->resowner; PortalContext = PortalGetHeapMemory(portal); QueryContext = portal->queryContext; @@ -1276,11 +1272,11 @@ DoPortalRunFetch(Portal portal, if (count > 0) { /* - * Definition: Rewind to start, advance count-1 rows, - * return next row (if any). In practice, if the goal is - * less than halfway back to the start, it's better to - * scan from where we are. In any case, we arrange to - * fetch the target row going forwards. + * Definition: Rewind to start, advance count-1 rows, return + * next row (if any). In practice, if the goal is less than + * halfway back to the start, it's better to scan from where + * we are. In any case, we arrange to fetch the target row + * going forwards. */ if (portal->posOverflow || portal->portalPos == LONG_MAX || count - 1 <= portal->portalPos / 2) @@ -1309,11 +1305,10 @@ DoPortalRunFetch(Portal portal, { /* * Definition: Advance to end, back up abs(count)-1 rows, - * return prior row (if any). We could optimize this if - * we knew in advance where the end was, but typically we - * won't. (Is it worth considering case where count > half - * of size of query? We could rewind once we know the - * size ...) + * return prior row (if any). We could optimize this if we + * knew in advance where the end was, but typically we won't. + * (Is it worth considering case where count > half of size of + * query? We could rewind once we know the size ...) */ PortalRunSelect(portal, true, FETCH_ALL, None_Receiver); if (count < -1) @@ -1332,8 +1327,7 @@ DoPortalRunFetch(Portal portal, if (count > 0) { /* - * Definition: advance count-1 rows, return next row (if - * any). + * Definition: advance count-1 rows, return next row (if any). */ if (count > 1) PortalRunSelect(portal, true, count - 1, None_Receiver); @@ -1342,8 +1336,8 @@ DoPortalRunFetch(Portal portal, else if (count < 0) { /* - * Definition: back up abs(count)-1 rows, return prior row - * (if any). + * Definition: back up abs(count)-1 rows, return prior row (if + * any). */ if (count < -1) PortalRunSelect(portal, false, -count - 1, None_Receiver); @@ -1362,8 +1356,8 @@ DoPortalRunFetch(Portal portal, } /* - * Get here with fdirection == FETCH_FORWARD or FETCH_BACKWARD, and - * count >= 0. + * Get here with fdirection == FETCH_FORWARD or FETCH_BACKWARD, and count + * >= 0. */ forward = (fdirection == FETCH_FORWARD); @@ -1385,11 +1379,11 @@ DoPortalRunFetch(Portal portal, else { /* - * If we are sitting on a row, back up one so we can re-fetch - * it. If we are not sitting on a row, we still have to start - * up and shut down the executor so that the destination is - * initialized and shut down correctly; so keep going. To - * PortalRunSelect, count == 0 means we will retrieve no row. + * If we are sitting on a row, back up one so we can re-fetch it. + * If we are not sitting on a row, we still have to start up and + * shut down the executor so that the destination is initialized + * and shut down correctly; so keep going. To PortalRunSelect, + * count == 0 means we will retrieve no row. */ if (on_row) { |