Fix core dump in duration logging for a V3-protocol Execute message

when what's being executed is a COMMIT or ROLLBACK.  Per report from
Sergey Koposov.  Backpatch to 8.1; 8.0 and before don't have the bug
due to lack of any logging at all here.

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index e2d5829d0b4151e278fbb987655ee22f05bfcb02..945eee571f26378986d7cba549742f210135383c 100644 (file)
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.468.2.5 2006/06/11 15:49:36 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.468.2.6 2006/08/13 22:18:22 tgl Exp $
  *
  * NOTES
  *       this is the "main" module of the postgres backend and
@@ -1642,12 +1642,14 @@ exec_execute_message(const char *portal_name, long max_rows)
        Portal          portal;
        bool            completed;
        char            completionTag[COMPLETION_TAG_BUFSIZE];
+       const char *sourceText = NULL;
        struct timeval start_t,
                                stop_t;
        bool            save_log_duration = log_duration;
        int                     save_log_min_duration_statement = log_min_duration_statement;
        bool            save_log_statement_stats = log_statement_stats;
-       bool            execute_is_fetch = false;
+       bool            is_xact_command;
+       bool            execute_is_fetch;
 
        /* Adjust destination to tell printtup.c what to do */
        dest = whereToSendOutput;
@@ -1660,15 +1662,6 @@ exec_execute_message(const char *portal_name, long max_rows)
                                (errcode(ERRCODE_UNDEFINED_CURSOR),
                                 errmsg("portal \"%s\" does not exist", portal_name)));
 
-       /*
-        * If we re-issue an Execute protocol request against an existing portal,
-        * then we are only fetching more rows rather than completely re-executing
-        * the query from the start. atStart is never reset for a v3 portal, so we
-        * are safe to use this check.
-        */
-       if (!portal->atStart)
-               execute_is_fetch = true;
-
        /*
         * If the original query was a null string, just return
         * EmptyQueryResponse.
@@ -1680,6 +1673,17 @@ exec_execute_message(const char *portal_name, long max_rows)
                return;
        }
 
+       /* Does the portal contain a transaction command? */
+       is_xact_command = IsTransactionStmtList(portal->parseTrees);
+
+       /*
+        * If we re-issue an Execute protocol request against an existing portal,
+        * then we are only fetching more rows rather than completely re-executing
+        * the query from the start. atStart is never reset for a v3 portal, so we
+        * are safe to use this check.
+        */
+       execute_is_fetch = !portal->atStart;
+
        /* Should we display the portal names here? */
        if (execute_is_fetch)
        {
@@ -1688,8 +1692,18 @@ exec_execute_message(const char *portal_name, long max_rows)
        }
        else if (portal->sourceText)
        {
-               debug_query_string = portal->sourceText;
-               pgstat_report_activity(portal->sourceText);
+               /*
+                * We must copy the sourceText into MessageContext in case the
+                * portal is destroyed during finish_xact_command.  Can avoid
+                * the copy if it's not an xact command, though.
+                */
+               if (is_xact_command)
+                       sourceText = pstrdup(portal->sourceText);
+               else
+                       sourceText = portal->sourceText;
+
+               debug_query_string = sourceText;
+               pgstat_report_activity(sourceText);
        }
        else
        {
@@ -1712,12 +1726,11 @@ exec_execute_message(const char *portal_name, long max_rows)
                ResetUsage();
 
        if (log_statement == LOGSTMT_ALL)
-               /* We have the portal, so output the source query. */
                ereport(LOG,
                                (errmsg("statement: %sEXECUTE %s  [PREPARE:  %s]",
                                                (execute_is_fetch) ? "FETCH from " : "",
                                                (*portal_name != '\0') ? portal_name : "<unnamed>",
-                                               portal->sourceText ? portal->sourceText : "")));
+                                               sourceText ? sourceText : "")));
 
        BeginCommand(portal->commandTag, dest);
 
@@ -1763,7 +1776,7 @@ exec_execute_message(const char *portal_name, long max_rows)
 
        if (completed)
        {
-               if (IsTransactionStmtList(portal->parseTrees))
+               if (is_xact_command)
                {
                        /*
                         * If this was a transaction control statement, commit it.      We
@@ -1828,8 +1841,8 @@ exec_execute_message(const char *portal_name, long max_rows)
                                                                  (stop_t.tv_usec - start_t.tv_usec) / 1000),
                                                        (long) (stop_t.tv_usec - start_t.tv_usec) % 1000,
                                                        (execute_is_fetch) ? "FETCH from " : "",
-                                                 (*portal_name != '\0') ? portal_name : "<unnamed>",
-                                                       portal->sourceText ? portal->sourceText : "")));
+                                                       (*portal_name != '\0') ? portal_name : "<unnamed>",
+                                                       sourceText ? sourceText : "")));
        }
 
        if (save_log_statement_stats)