Add pg_stat_reset_shared('bgwriter') to reset the cluster-wide shared

statistics of the bgwriter.

Greg Smith

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index f56fd214ae4a0278344a4c5506c019f8fa90197d..940b8b79ffe5940a0a8b9a9b38136d69c276d6c4 100644 (file)
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/monitoring.sgml,v 1.73 2009/11/29 18:14:30 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/monitoring.sgml,v 1.74 2010/01/19 14:11:30 mha Exp $ -->
 
 <chapter id="monitoring">
  <title>Monitoring Database Activity</title>
@@ -918,6 +918,17 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
        (requires superuser privileges)
       </entry>
      </row>
+
+     <row>
+      <entry><literal><function>pg_stat_reset_shared</function>(text)</literal></entry>
+      <entry><type>void</type></entry>
+      <entry>
+       Reset some of the shared statistics counters for the database cluster to
+       zero (requires superuser privileges).  Calling
+       <literal>pg_stat_reset_shared('bgwriter')</> will zero all the values shown by
+       <structname>pg_stat_bgwriter</>.
+      </entry>
+     </row>
     </tbody>
    </tgroup>
   </table>

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index e45cdaa8e8d1d8f197a1160ecfbea1b3774d8e13..2d716d8576382ba5141fc07cb1be315191a52fd6 100644 (file)
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -13,7 +13,7 @@
  *
  *     Copyright (c) 2001-2010, PostgreSQL Global Development Group
  *
- *     $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.197 2010/01/10 14:16:07 mha Exp $
+ *     $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.198 2010/01/19 14:11:30 mha Exp $
  * ----------
  */
 #include "postgres.h"
@@ -270,6 +270,7 @@ static void pgstat_recv_tabstat(PgStat_MsgTabstat *msg, int len);
 static void pgstat_recv_tabpurge(PgStat_MsgTabpurge *msg, int len);
 static void pgstat_recv_dropdb(PgStat_MsgDropdb *msg, int len);
 static void pgstat_recv_resetcounter(PgStat_MsgResetcounter *msg, int len);
+static void pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len);
 static void pgstat_recv_autovac(PgStat_MsgAutovacStart *msg, int len);
 static void pgstat_recv_vacuum(PgStat_MsgVacuum *msg, int len);
 static void pgstat_recv_analyze(PgStat_MsgAnalyze *msg, int len);
@@ -1153,6 +1154,38 @@ pgstat_reset_counters(void)
        pgstat_send(&msg, sizeof(msg));
 }
 
+/* ----------
+ * pgstat_reset_shared_counters() -
+ *
+ *     Tell the statistics collector to reset cluster-wide shared counters.
+ * ----------
+ */
+void
+pgstat_reset_shared_counters(const char *target)
+{
+       PgStat_MsgResetsharedcounter msg;
+
+       if (pgStatSock < 0)
+               return;
+
+       if (!superuser())
+               ereport(ERROR,
+                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                                errmsg("must be superuser to reset statistics counters")));
+
+       if (strcmp(target, "bgwriter") == 0)
+               msg.m_resettarget = RESET_BGWRITER;
+       else
+       {
+               ereport(ERROR,
+                               (errcode(ERRCODE_SYNTAX_ERROR),
+                                errmsg("unrecognized reset target: '%s'", target),
+                                errhint("allowed targets are 'bgwriter'.")));
+       }
+
+       pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
+       pgstat_send(&msg, sizeof(msg));
+}
 
 /* ----------
  * pgstat_report_autovac() -
@@ -2915,6 +2948,12 @@ PgstatCollectorMain(int argc, char *argv[])
                                                                                         len);
                                        break;
 
+                               case PGSTAT_MTYPE_RESETSHAREDCOUNTER:
+                                       pgstat_recv_resetsharedcounter(
+                                                                                        (PgStat_MsgResetsharedcounter *) &msg,
+                                                                                        len);
+                                       break;
+
                                case PGSTAT_MTYPE_AUTOVAC_START:
                                        pgstat_recv_autovac((PgStat_MsgAutovacStart *) &msg, len);
                                        break;
@@ -3868,6 +3907,27 @@ pgstat_recv_resetcounter(PgStat_MsgResetcounter *msg, int len)
                                                                         HASH_ELEM | HASH_FUNCTION);
 }
 
+/* ----------
+ * pgstat_recv_resetshared() -
+ *
+ *     Reset some shared statistics of the cluster.
+ * ----------
+ */
+static void
+pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
+{
+    if (msg->m_resettarget==RESET_BGWRITER)
+       {
+               /* Reset the global background writer statistics for the cluster. */
+               memset(&globalStats, 0, sizeof(globalStats));
+       }
+
+       /*
+        * Presumably the sender of this message validated the target, don't
+        * complain here if it's not valid
+        */
+}
+
 /* ----------
  * pgstat_recv_autovac() -
  *

diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 16fa10f2cd95d589ad2c1ee436f8978207bbfc60..06dfd3bc93bfe3a9d61a1aab0dd5d2fe7e7e5965 100644 (file)
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/adt/pgstatfuncs.c,v 1.57 2010/01/02 16:57:54 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/adt/pgstatfuncs.c,v 1.58 2010/01/19 14:11:31 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -78,6 +78,7 @@ extern Datum pg_stat_get_buf_alloc(PG_FUNCTION_ARGS);
 
 extern Datum pg_stat_clear_snapshot(PG_FUNCTION_ARGS);
 extern Datum pg_stat_reset(PG_FUNCTION_ARGS);
+extern Datum pg_stat_reset_shared(PG_FUNCTION_ARGS);
 
 /* Global bgwriter statistics, from bgwriter.c */
 extern PgStat_MsgBgWriter bgwriterStats;
@@ -1108,3 +1109,14 @@ pg_stat_reset(PG_FUNCTION_ARGS)
 
        PG_RETURN_VOID();
 }
+
+/* Reset some shared cluster-wide counters */
+Datum
+pg_stat_reset_shared(PG_FUNCTION_ARGS)
+{
+       char    *target = text_to_cstring(PG_GETARG_TEXT_PP(0));
+
+       pgstat_reset_shared_counters(target);
+
+       PG_RETURN_VOID();
+}

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 9b36997499a80ee7136af70eaf5bb5c702907069..f37b9077a9be9d9d58a8d989c267d75812cf07cb 100644 (file)
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.575 2010/01/19 05:50:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.576 2010/01/19 14:11:32 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*                                                     yyyymmddN */
-#define CATALOG_VERSION_NO     201001181
+#define CATALOG_VERSION_NO     201001191
 
 #endif

diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e5d6b402b70781475a22b20a288e48d0b6a5b82d..9b910317a20864f32dc318220acae527dac1b270 100644 (file)
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.563 2010/01/19 05:50:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.564 2010/01/19 14:11:32 mha Exp $
  *
  * NOTES
  *       The script catalog/genbki.pl reads this file and generates .bki
@@ -3073,6 +3073,8 @@ DATA(insert OID = 2230 (  pg_stat_clear_snapshot          PGNSP PGUID 12 1 0 0 f f f f f
 DESCR("statistics: discard current transaction's statistics snapshot");
 DATA(insert OID = 2274 (  pg_stat_reset                                        PGNSP PGUID 12 1 0 0 f f f f f v 0 0 2278 "" _null_ _null_ _null_ _null_        pg_stat_reset _null_ _null_ _null_ ));
 DESCR("statistics: reset collected statistics for current database");
+DATA(insert OID = 3775 (  pg_stat_reset_shared                 PGNSP PGUID 12 1 0 0 f f f f f v 1 0 2278 "25" _null_ _null_ _null_ _null_      pg_stat_reset_shared _null_ _null_ _null_ ));
+DESCR("statistics: reset collected statistics shared across the cluster");
 
 DATA(insert OID = 1946 (  encode                                               PGNSP PGUID 12 1 0 0 f f f t f i 2 0 25 "17 25" _null_ _null_ _null_ _null_ binary_encode _null_ _null_ _null_ ));
 DESCR("convert bytea value into some ascii-only text string");

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index edd544944b6c60d3df82209137176a4e25106600..acadef35a201e506c1336a17c367a1a68553fb55 100644 (file)
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -5,7 +5,7 @@
  *
  *     Copyright (c) 2001-2010, PostgreSQL Global Development Group
  *
- *     $PostgreSQL: pgsql/src/include/pgstat.h,v 1.86 2010/01/02 16:58:00 momjian Exp $
+ *     $PostgreSQL: pgsql/src/include/pgstat.h,v 1.87 2010/01/19 14:11:31 mha Exp $
  * ----------
  */
 #ifndef PGSTAT_H
@@ -38,6 +38,7 @@ typedef enum StatMsgType
        PGSTAT_MTYPE_TABPURGE,
        PGSTAT_MTYPE_DROPDB,
        PGSTAT_MTYPE_RESETCOUNTER,
+       PGSTAT_MTYPE_RESETSHAREDCOUNTER,
        PGSTAT_MTYPE_AUTOVAC_START,
        PGSTAT_MTYPE_VACUUM,
        PGSTAT_MTYPE_ANALYZE,
@@ -93,6 +94,12 @@ typedef struct PgStat_TableCounts
        PgStat_Counter t_blocks_hit;
 } PgStat_TableCounts;
 
+/* Possible targets for resetting cluster-wide shared values */
+typedef enum PgStat_Shared_Reset_Target
+{
+    RESET_BGWRITER
+} PgStat_Shared_Reset_Target;
+
 
 /* ------------------------------------------------------------
  * Structures kept in backend local memory while accumulating counts
@@ -260,6 +267,16 @@ typedef struct PgStat_MsgResetcounter
        Oid                     m_databaseid;
 } PgStat_MsgResetcounter;
 
+/* ----------
+ * PgStat_MsgResetsharedcounter        Sent by the backend to tell the collector
+ *                                                             to reset a shared counter
+ * ----------
+ */
+typedef struct PgStat_MsgResetsharedcounter
+{
+       PgStat_MsgHdr m_hdr;
+       PgStat_Shared_Reset_Target m_resettarget;
+} PgStat_MsgResetsharedcounter;
 
 /* ----------
  * PgStat_MsgAutovacStart              Sent by the autovacuum daemon to signal
@@ -414,6 +431,7 @@ typedef union PgStat_Msg
        PgStat_MsgTabpurge msg_tabpurge;
        PgStat_MsgDropdb msg_dropdb;
        PgStat_MsgResetcounter msg_resetcounter;
+       PgStat_MsgResetsharedcounter msg_resetsharedcounter;
        PgStat_MsgAutovacStart msg_autovacuum;
        PgStat_MsgVacuum msg_vacuum;
        PgStat_MsgAnalyze msg_analyze;
@@ -635,6 +653,7 @@ extern void pgstat_drop_database(Oid databaseid);
 
 extern void pgstat_clear_snapshot(void);
 extern void pgstat_reset_counters(void);
+extern void pgstat_reset_shared_counters(const char *);
 
 extern void pgstat_report_autovac(Oid dboid);
 extern void pgstat_report_vacuum(Oid tableoid, bool shared, bool adopt_counts,