Fix dblink and tablefunc to not return with the wrong CurrentMemoryContext.

Per buildfarm results.

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index e09d6f16f6973c037ad4f544566f51ee1efcb17d..9c92ee51760e8bad5e1f85ea195ca8f3e87b336a 100644 (file)
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -8,7 +8,7 @@
  * Darko Prenosil <Darko.Prenosil@finteh.hr>
  * Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
  *
- * $PostgreSQL: pgsql/contrib/dblink/dblink.c,v 1.69 2008/01/14 02:49:47 tgl Exp $
+ * $PostgreSQL: pgsql/contrib/dblink/dblink.c,v 1.69.2.1 2008/11/30 23:24:01 tgl Exp $
  * Copyright (c) 2001-2008, PostgreSQL Global Development Group
  * ALL RIGHTS RESERVED;
  *
@@ -226,7 +226,6 @@ dblink_connect(PG_FUNCTION_ARGS)
        char       *connstr = NULL;
        char       *connname = NULL;
        char       *msg;
-       MemoryContext oldcontext;
        PGconn     *conn = NULL;
        remoteConn *rconn = NULL;
 
@@ -240,13 +239,11 @@ dblink_connect(PG_FUNCTION_ARGS)
        else if (PG_NARGS() == 1)
                connstr = GET_STR(PG_GETARG_TEXT_P(0));
 
-       oldcontext = MemoryContextSwitchTo(TopMemoryContext);
-
        if (connname)
-               rconn = (remoteConn *) palloc(sizeof(remoteConn));
-       conn = PQconnectdb(connstr);
+               rconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext,
+                                                                                                 sizeof(remoteConn));
 
-       MemoryContextSwitchTo(oldcontext);
+       conn = PQconnectdb(connstr);
 
        if (PQstatus(conn) == CONNECTION_BAD)
        {
@@ -583,10 +580,10 @@ dblink_fetch(PG_FUNCTION_ARGS)
                funcctx = SRF_FIRSTCALL_INIT();
 
                /*
-                * switch to memory context appropriate for multiple function calls
+                * Try to execute the query.  Note that since libpq uses malloc,
+                * the PGresult will be long-lived even though we are still in
+                * a short-lived memory context.
                 */
-               oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
-
                res = PQexec(conn, buf.data);
                if (!res ||
                        (PQresultStatus(res) != PGRES_COMMAND_OK &&
@@ -633,9 +630,6 @@ dblink_fetch(PG_FUNCTION_ARGS)
                                break;
                }
 
-               /* make sure we have a persistent copy of the tupdesc */
-               tupdesc = CreateTupleDescCopy(tupdesc);
-
                /* check result and tuple descriptor have the same number of columns */
                if (PQnfields(res) != tupdesc->natts)
                        ereport(ERROR,
@@ -643,14 +637,25 @@ dblink_fetch(PG_FUNCTION_ARGS)
                                         errmsg("remote query result rowtype does not match "
                                                        "the specified FROM clause rowtype")));
 
-               /* fast track when no results */
+               /*
+                * fast track when no results.  We could exit earlier, but then
+                * we'd not report error if the result tuple type is wrong.
+                */
                if (funcctx->max_calls < 1)
                {
-                       if (res)
-                               PQclear(res);
+                       PQclear(res);
                        SRF_RETURN_DONE(funcctx);
                }
 
+               /*
+                * switch to memory context appropriate for multiple function calls,
+                * so we can make long-lived copy of tupdesc etc
+                */
+               oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+
+               /* make sure we have a persistent copy of the tupdesc */
+               tupdesc = CreateTupleDescCopy(tupdesc);
+
                /* store needed metadata for subsequent calls */
                attinmeta = TupleDescGetAttInMetadata(tupdesc);
                funcctx->attinmeta = attinmeta;
@@ -841,7 +846,10 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async, bool do_get)
                                res = PQgetResult(conn);
                                /* NULL means we're all done with the async results */
                                if (!res)
+                               {
+                                       MemoryContextSwitchTo(oldcontext);
                                        SRF_RETURN_DONE(funcctx);
+                               }
                        }
 
                        if (!res ||
@@ -855,6 +863,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async, bool do_get)
                                        DBLINK_RES_ERROR_AS_NOTICE("sql error");
                                        if (freeconn)
                                                PQfinish(conn);
+                                       MemoryContextSwitchTo(oldcontext);
                                        SRF_RETURN_DONE(funcctx);
                                }
                        }
@@ -925,6 +934,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async, bool do_get)
                        {
                                if (res)
                                        PQclear(res);
+                               MemoryContextSwitchTo(oldcontext);
                                SRF_RETURN_DONE(funcctx);
                        }
 
@@ -1296,8 +1306,11 @@ dblink_get_pkey(PG_FUNCTION_ARGS)
                        funcctx->user_fctx = results;
                }
                else
+               {
                        /* fast track when no results */
+                       MemoryContextSwitchTo(oldcontext);
                        SRF_RETURN_DONE(funcctx);
+               }
 
                MemoryContextSwitchTo(oldcontext);
        }

diff --git a/contrib/tablefunc/tablefunc.c b/contrib/tablefunc/tablefunc.c
index bfac89e4146b1344675b3e00de2e311b72f7b348..9c9d0aa7a29f499bea7fae2517a4da6561d7f691 100644 (file)
--- a/contrib/tablefunc/tablefunc.c
+++ b/contrib/tablefunc/tablefunc.c
@@ -378,11 +378,6 @@ crosstab(PG_FUNCTION_ARGS)
                /* 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);
-
                /* Connect to SPI manager */
                if ((ret = SPI_connect()) < 0)
                        /* internal error */
@@ -423,9 +418,6 @@ crosstab(PG_FUNCTION_ARGS)
                        SRF_RETURN_DONE(funcctx);
                }
 
-               /* SPI switches context on us, so reset it */
-               MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
-
                /* get a tuple descriptor for our result type */
                switch (get_call_result_type(fcinfo, NULL, &tupdesc))
                {
@@ -445,9 +437,6 @@ crosstab(PG_FUNCTION_ARGS)
                                break;
                }
 
-               /* make sure we have a persistent copy of the tupdesc */
-               tupdesc = CreateTupleDescCopy(tupdesc);
-
                /*
                 * Check that return tupdesc is compatible with the data we got from
                 * SPI, at least based on number and type of attributes
@@ -458,6 +447,14 @@ crosstab(PG_FUNCTION_ARGS)
                                         errmsg("return and sql tuple descriptions are " \
                                                        "incompatible")));
 
+               /*
+                * switch to memory context appropriate for multiple function calls
+                */
+               oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+
+               /* make sure we have a persistent copy of the tupdesc */
+               tupdesc = CreateTupleDescCopy(tupdesc);
+
                /*
                 * Generate attribute metadata needed later to produce tuples from raw
                 * C strings