Prevent auto_explain from changing the output of a user's EXPLAIN.

Commit af7914c6627bcf0b0ca614e9ce95d3f8056602bf, which introduced the
EXPLAIN (TIMING) option, for some reason coded explain.c to look at
planstate->instrument->need_timer rather than es->timing to decide
whether to print timing info.  However, the former flag might get set
as a result of contrib/auto_explain wanting timing information.  We
certainly don't want activation of auto_explain to change user-visible
statement behavior, so fix that.

Also fix an independent bug introduced in the same patch: in the code
path for a never-executed node with a machine-friendly output format,
if timing was selected, it would fail to print the Actual Rows and Actual
Loops items.

Per bug #10404 from Tomonari Katsumata.  Back-patch to 9.2 where the
faulty code was introduced.

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index e51c08b85dd5cb5fc4ade77cc7c65b54d662846d..fe43942f3b7ed839a3ed586b3a16730ba1da116f 100644 (file)
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1145,11 +1145,18 @@ ExplainNode(PlanState *planstate, List *ancestors,
    /*
     * We have to forcibly clean up the instrumentation state because we
     * haven't done ExecutorEnd yet.  This is pretty grotty ...
+    *
+    * Note: contrib/auto_explain could cause instrumentation to be set up
+    * even though we didn't ask for it here.  Be careful not to print any
+    * instrumentation results the user didn't ask for.  But we do the
+    * InstrEndLoop call anyway, if possible, to reduce the number of cases
+    * auto_explain has to contend with.
     */
    if (planstate->instrument)
        InstrEndLoop(planstate->instrument);
 
-   if (planstate->instrument && planstate->instrument->nloops > 0)
+   if (es->analyze &&
+       planstate->instrument && planstate->instrument->nloops > 0)
    {
        double      nloops = planstate->instrument->nloops;
        double      startup_sec = 1000.0 * planstate->instrument->startup / nloops;
@@ -1158,7 +1165,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 
        if (es->format == EXPLAIN_FORMAT_TEXT)
        {
-           if (planstate->instrument->need_timer)
+           if (es->timing)
                appendStringInfo(es->str,
                            " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
                                 startup_sec, total_sec, rows, nloops);
@@ -1169,7 +1176,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
        }
        else
        {
-           if (planstate->instrument->need_timer)
+           if (es->timing)
            {
                ExplainPropertyFloat("Actual Startup Time", startup_sec, 3, es);
                ExplainPropertyFloat("Actual Total Time", total_sec, 3, es);
@@ -1180,20 +1187,18 @@ ExplainNode(PlanState *planstate, List *ancestors,
    }
    else if (es->analyze)
    {
-
        if (es->format == EXPLAIN_FORMAT_TEXT)
            appendStringInfo(es->str, " (never executed)");
-       else if (planstate->instrument->need_timer)
-       {
-           ExplainPropertyFloat("Actual Startup Time", 0.0, 3, es);
-           ExplainPropertyFloat("Actual Total Time", 0.0, 3, es);
-       }
        else
        {
+           if (es->timing)
+           {
+               ExplainPropertyFloat("Actual Startup Time", 0.0, 3, es);
+               ExplainPropertyFloat("Actual Total Time", 0.0, 3, es);
+           }
            ExplainPropertyFloat("Actual Rows", 0.0, 0, es);
            ExplainPropertyFloat("Actual Loops", 0.0, 0, es);
        }
-
    }
 
    /* in text format, first line ends here */
@@ -1362,7 +1367,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
    }
 
    /* Show buffer usage */
-   if (es->buffers)
+   if (es->buffers && planstate->instrument)
    {
        const BufferUsage *usage = &planstate->instrument->bufusage;