Add a trace_sort option to help with measuring resource usage of external

sort operations.  Per recent discussion.  Simon Riggs and Tom Lane.

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d239654b47b570394348afb448ebf93ce157f183..710605ca7002263a5f6ae52a0b1fe2d3326e5e46 100644 (file)
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1,5 +1,5 @@
 
 
   Run-time Configuration
@@ -4071,6 +4071,21 @@ plruby.use_strict = true        # generates error: unknown class name
       
      
 
+     
+      trace_sort (boolean)
+      
+       trace_sort configuration parameter
+      
+      
+       
+        If on, emit information about resource usage during sort operations.
+        This option is only available if the TRACE_SORT macro
+        was defined when PostgreSQL was compiled.
+        (However, TRACE_SORT is currently defined by default.)
+       
+      
+     
+
      
       trace_locks (boolean)
       trace_lwlocks (boolean)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 1315afff0c2b006336ef25865c753e1b5a919f03..d9932e05177c9585e94a4e795ae30904dfcaacb2 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut .
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.289 2005/09/24 22:54:39 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.290 2005/10/03 22:55:51 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -92,6 +92,9 @@ extern int    CommitDelay;
 extern int CommitSiblings;
 extern char *default_tablespace;
 extern bool    fullPageWrites;
+#ifdef TRACE_SORT
+extern bool    trace_sort;
+#endif
 
 static const char *assign_log_destination(const char *value,
                       bool doit, GucSource source);
@@ -891,6 +894,18 @@ static struct config_bool ConfigureNamesBool[] =
        false, NULL, NULL
    },
 
+#ifdef TRACE_SORT
+   {
+       {"trace_sort", PGC_USERSET, DEVELOPER_OPTIONS,
+           gettext_noop("Emit information about resource usage in sorting."),
+           NULL,
+           GUC_NOT_IN_SAMPLE
+       },
+       &trace_sort,
+       false, NULL, NULL
+   },
+#endif
+
 #ifdef WAL_DEBUG
    {
        {"wal_debug", PGC_SUSET, DEVELOPER_OPTIONS,

diff --git a/src/backend/utils/sort/tuplesort.c b/src/backend/utils/sort/tuplesort.c
index 3ec1cf127f3cf3cc3a53da90a4c994b7dd3c6f19..53f2b546f462480cb59a5c4f80dde584976a53f9 100644 (file)
--- a/src/backend/utils/sort/tuplesort.c
+++ b/src/backend/utils/sort/tuplesort.c
@@ -78,7 +78,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/utils/sort/tuplesort.c,v 1.50 2005/09/23 15:36:57 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/utils/sort/tuplesort.c,v 1.51 2005/10/03 22:55:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -95,10 +95,17 @@
 #include "utils/logtape.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
+#include "utils/pg_rusage.h"
 #include "utils/syscache.h"
 #include "utils/tuplesort.h"
 
 
+/* GUC variable */
+#ifdef TRACE_SORT
+bool           trace_sort = false;
+#endif
+
+
 /*
  * Possible states of a Tuplesort object.  These denote the states that
  * persist between calls of Tuplesort routines.
@@ -283,6 +290,13 @@ struct Tuplesortstate
    /* we need typelen and byval in order to know how to copy the Datums. */
    int         datumTypeLen;
    bool        datumTypeByVal;
+
+   /*
+    * Resource snapshot for time of sort start.
+    */
+#ifdef TRACE_SORT
+   PGRUsage    ru_start;
+#endif
 };
 
 #define COMPARETUP(state,a,b)  ((*(state)->comparetup) (state, a, b))
@@ -422,6 +436,11 @@ tuplesort_begin_common(int workMem, bool randomAccess)
 
    state = (Tuplesortstate *) palloc0(sizeof(Tuplesortstate));
 
+#ifdef TRACE_SORT
+   if (trace_sort)
+       pg_rusage_init(&state->ru_start);
+#endif
+
    state->status = TSS_INITIAL;
    state->randomAccess = randomAccess;
    state->availMem = workMem * 1024L;
@@ -456,6 +475,13 @@ tuplesort_begin_heap(TupleDesc tupDesc,
 
    AssertArg(nkeys > 0);
 
+#ifdef TRACE_SORT
+   if (trace_sort)
+       elog(NOTICE,
+            "begin tuple sort: nkeys = %d, workMem = %d, randomAccess = %c",
+            nkeys, workMem, randomAccess ? 't' : 'f');
+#endif
+
    state->comparetup = comparetup_heap;
    state->copytup = copytup_heap;
    state->writetup = writetup_heap;
@@ -499,6 +525,14 @@ tuplesort_begin_index(Relation indexRel,
 {
    Tuplesortstate *state = tuplesort_begin_common(workMem, randomAccess);
 
+#ifdef TRACE_SORT
+   if (trace_sort)
+       elog(NOTICE,
+            "begin index sort: unique = %c, workMem = %d, randomAccess = %c",
+            enforceUnique ? 't' : 'f',
+            workMem, randomAccess ? 't' : 'f');
+#endif
+
    state->comparetup = comparetup_index;
    state->copytup = copytup_index;
    state->writetup = writetup_index;
@@ -522,6 +556,13 @@ tuplesort_begin_datum(Oid datumType,
    int16       typlen;
    bool        typbyval;
 
+#ifdef TRACE_SORT
+   if (trace_sort)
+       elog(NOTICE,
+            "begin datum sort: workMem = %d, randomAccess = %c",
+            workMem, randomAccess ? 't' : 'f');
+#endif
+
    state->comparetup = comparetup_datum;
    state->copytup = copytup_datum;
    state->writetup = writetup_datum;
@@ -573,6 +614,12 @@ tuplesort_end(Tuplesortstate *state)
    if (state->sortFnKinds)
        pfree(state->sortFnKinds);
 
+#ifdef TRACE_SORT
+   if (trace_sort)
+       elog(NOTICE, "sort ended: %s",
+            pg_rusage_show(&state->ru_start));
+#endif
+
    pfree(state);
 }
 
@@ -712,6 +759,12 @@ puttuple_common(Tuplesortstate *state, void *tuple)
 void
 tuplesort_performsort(Tuplesortstate *state)
 {
+#ifdef TRACE_SORT
+   if (trace_sort)
+       elog(NOTICE, "performsort starting: %s",
+            pg_rusage_show(&state->ru_start));
+#endif
+
    switch (state->status)
    {
        case TSS_INITIAL:
@@ -751,6 +804,13 @@ tuplesort_performsort(Tuplesortstate *state)
            elog(ERROR, "invalid tuplesort state");
            break;
    }
+
+#ifdef TRACE_SORT
+   if (trace_sort)
+       elog(NOTICE, "performsort done%s: %s",
+            (state->status == TSS_FINALMERGE) ? " (except final merge)" : "",
+            pg_rusage_show(&state->ru_start));
+#endif
 }
 
 /*
@@ -986,6 +1046,12 @@ inittapes(Tuplesortstate *state)
    int         ntuples,
                j;
 
+#ifdef TRACE_SORT
+   if (trace_sort)
+       elog(NOTICE, "switching to external sort: %s",
+            pg_rusage_show(&state->ru_start));
+#endif
+
    state->tapeset = LogicalTapeSetCreate(MAXTAPES);
 
    /*
@@ -1243,6 +1309,12 @@ mergeonerun(Tuplesortstate *state)
     */
    markrunend(state, destTape);
    state->tp_runs[TAPERANGE]++;
+
+#ifdef TRACE_SORT
+   if (trace_sort)
+       elog(NOTICE, "finished merge step: %s",
+            pg_rusage_show(&state->ru_start));
+#endif
 }
 
 /*
@@ -1456,6 +1528,14 @@ dumptuples(Tuplesortstate *state, bool alltuples)
            state->tp_runs[state->destTape]++;
            state->tp_dummy[state->destTape]--; /* per Alg D step D2 */
 
+#ifdef TRACE_SORT
+           if (trace_sort)
+               elog(NOTICE, "finished writing%s run %d: %s",
+                    (state->memtupcount == 0) ? " final" : "",
+                    state->currentRun,
+                    pg_rusage_show(&state->ru_start));
+#endif
+
            /*
             * Done if heap is empty, else prepare for new run.
             */

diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index b36714b87bd2e03b5e3011e6b492aff36f977b35..bf82771d45c90380ba308dc4d7a634aaf124fd4a 100644 (file)
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -6,7 +6,7 @@
  * for developers. If you edit any of these, be sure to do a *full*
  * rebuild (and an initdb if noted).
  *
- * $PostgreSQL: pgsql/src/include/pg_config_manual.h,v 1.16 2005/03/29 03:01:32 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/pg_config_manual.h,v 1.17 2005/10/03 22:55:56 tgl Exp $
  *------------------------------------------------------------------------
  */
 
@@ -229,11 +229,15 @@
  */
 /* #define WAL_DEBUG */
 
+/*
+ * Enable tracing of resource consumption during sort operations;
+ * see also the trace_sort GUC var.  For 8.1 this is enabled by default.
+ */
+#define TRACE_SORT 1
+
 /*
  * Other debug #defines (documentation, anyone?)
  */
-/* #define IPORTAL_DEBUG  */
-/* #define HEAPDEBUGALL  */
+/* #define HEAPDEBUGALL */
 /* #define ACLDEBUG */
 /* #define RTDEBUG */
-/* #define GISTDEBUG */