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)