Adjust error-handling logic in libpq. For the first time, libpq copes

sanely with running out of memory for a query result.

diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index 7d0eb39f96cbe22cb638b0a9a24053ea91cf5379..df43f2cad2bc7c3738841e7a8513535d18264df0 100644 (file)
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.135 2003/05/08 18:16:37 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.136 2003/05/26 20:05:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -55,7 +55,7 @@ static void parseInput(PGconn *conn);
 static void handleSendFailure(PGconn *conn);
 static void handleSyncLoss(PGconn *conn, char id, int msgLength);
 static int getRowDescriptions(PGconn *conn);
-static int getAnotherTuple(PGconn *conn);
+static int getAnotherTuple(PGconn *conn, int msgLength);
 static int getParameterStatus(PGconn *conn);
 static int getNotify(PGconn *conn);
 
@@ -835,17 +835,28 @@ parseInput(PGconn *conn)
                    }
                    break;
                case 'D':       /* Data Row */
-                   if (conn->result != NULL)
+                   if (conn->result != NULL &&
+                       conn->result->resultStatus == PGRES_TUPLES_OK)
                    {
                        /* Read another tuple of a normal query response */
-                       if (getAnotherTuple(conn))
+                       if (getAnotherTuple(conn, msgLength))
                            return;
                    }
+                   else if (conn->result != NULL &&
+                            conn->result->resultStatus == PGRES_FATAL_ERROR)
+                   {
+                       /*
+                        * We've already choked for some reason.  Just discard
+                        * tuples till we get to the end of the query.
+                        */
+                       conn->inCursor += msgLength;
+                   }
                    else
                    {
-                       snprintf(noticeWorkspace, sizeof(noticeWorkspace),
+                       /* Set up to report error at end of query */
+                       printfPQExpBuffer(&conn->errorMessage,
                                 libpq_gettext("server sent data (\"D\" message) without prior row description (\"T\" message)\n"));
-                       DONOTICE(conn, noticeWorkspace);
+                       saveErrorResult(conn);
                        /* Discard the unexpected message */
                        conn->inCursor += msgLength;
                    }
@@ -888,6 +899,7 @@ parseInput(PGconn *conn)
                                      id);
                    /* build an error result holding the error message */
                    saveErrorResult(conn);
+                   /* not sure if we will see more, so go to ready state */
                    conn->asyncStatus = PGASYNC_READY;
                    /* Discard the unexpected message */
                    conn->inCursor += msgLength;
@@ -931,6 +943,7 @@ handleSyncLoss(PGconn *conn, char id, int msgLength)
    pqsecure_close(conn);
    closesocket(conn->sock);
    conn->sock = -1;
+   conn->asyncStatus = PGASYNC_READY; /* drop out of GetResult wait loop */
 }
 
 /*
@@ -1023,7 +1036,7 @@ getRowDescriptions(PGconn *conn)
  */
 
 static int
-getAnotherTuple(PGconn *conn)
+getAnotherTuple(PGconn *conn, int msgLength)
 {
    PGresult   *result = conn->result;
    int         nfields = result->numAttributes;
@@ -1050,12 +1063,11 @@ getAnotherTuple(PGconn *conn)
    if (tupnfields != nfields)
    {
        /* Replace partially constructed result with an error result */
-       pqClearAsyncResult(conn);
        printfPQExpBuffer(&conn->errorMessage,
                          libpq_gettext("unexpected field count in D message\n"));
        saveErrorResult(conn);
-       conn->asyncStatus = PGASYNC_READY;
        /* Discard the failed message by pretending we read it */
+       conn->inCursor = conn->inStart + 5 + msgLength;
        return 0;
    }
 
@@ -1102,14 +1114,15 @@ outOfMemory:
 
    /*
     * we do NOT use saveErrorResult() here, because of the likelihood
-    * that there's not enough memory to concatenate messages...
+    * that there's not enough memory to concatenate messages.  Instead,
+    * discard the old result first to try to win back some memory.
     */
    pqClearAsyncResult(conn);
    printfPQExpBuffer(&conn->errorMessage,
-                     libpq_gettext("out of memory\n"));
+                     libpq_gettext("out of memory for query result\n"));
    conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
-   conn->asyncStatus = PGASYNC_READY;
    /* Discard the failed message by pretending we read it */
+   conn->inCursor = conn->inStart + 5 + msgLength;
    return 0;
 }