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 7d0eb39..df43f2c 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;
 }