Add a hook to let loadable modules get control at ProcessUtility execution,

and use it to extend contrib/pg_stat_statements to track utility commands.

Itagaki Takahiro, reviewed by Euler Taveira de Oliveira.

diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index 01e4b5e5938c21dfffb5fc10a26fa9839f1318c6..e2b3afa4b6f36419013a892b58607d0d329a0bf6 100644 (file)
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -14,7 +14,7 @@
  * Copyright (c) 2008-2009, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/contrib/pg_stat_statements/pg_stat_statements.c,v 1.8 2009/12/15 04:57:46 rhaas Exp $
+ *       $PostgreSQL: pgsql/contrib/pg_stat_statements/pg_stat_statements.c,v 1.9 2009/12/15 20:04:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -32,6 +32,7 @@
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/spin.h"
+#include "tcop/utility.h"
 #include "utils/builtins.h"
 #include "utils/hsearch.h"
 #include "utils/guc.h"
@@ -113,6 +114,7 @@ static shmem_startup_hook_type prev_shmem_startup_hook = NULL;
 static ExecutorStart_hook_type prev_ExecutorStart = NULL;
 static ExecutorRun_hook_type prev_ExecutorRun = NULL;
 static ExecutorEnd_hook_type prev_ExecutorEnd = NULL;
+static ProcessUtility_hook_type prev_ProcessUtility = NULL;
 
 /* Links to shared memory state */
 static pgssSharedState *pgss = NULL;
@@ -124,7 +126,7 @@ typedef enum
 {
        PGSS_TRACK_NONE,                        /* track no statements */
        PGSS_TRACK_TOP,                         /* only top level statements */
-       PGSS_TRACK_ALL,                         /* all statements, including nested ones */
+       PGSS_TRACK_ALL                          /* all statements, including nested ones */
 } PGSSTrackLevel;
 
 static const struct config_enum_entry track_options[] = {
@@ -136,6 +138,7 @@ static const struct config_enum_entry track_options[] = {
 
 static int     pgss_max;                       /* max # statements to track */
 static int     pgss_track;                     /* tracking level */
+static bool pgss_track_utility;        /* whether to track utility commands */
 static bool pgss_save;                 /* whether to save stats across shutdown */
 
 
@@ -161,10 +164,12 @@ static void pgss_ExecutorRun(QueryDesc *queryDesc,
                                 ScanDirection direction,
                                 long count);
 static void pgss_ExecutorEnd(QueryDesc *queryDesc);
+static void pgss_ProcessUtility(Node *parsetree,
+                          const char *queryString, ParamListInfo params, bool isTopLevel,
+                          DestReceiver *dest, char *completionTag);
 static uint32 pgss_hash_fn(const void *key, Size keysize);
 static int     pgss_match_fn(const void *key1, const void *key2, Size keysize);
-static void pgss_store(const char *query,
-                  const Instrumentation *instr, uint32 rows);
+static void pgss_store(const char *query, double total_time, uint64 rows);
 static Size pgss_memsize(void);
 static pgssEntry *entry_alloc(pgssHashKey *key);
 static void entry_dealloc(void);
@@ -214,6 +219,16 @@ _PG_init(void)
                                                         NULL,
                                                         NULL);
 
+       DefineCustomBoolVariable("pg_stat_statements.track_utility",
+                          "Selects whether utility commands are tracked by pg_stat_statements.",
+                                                        NULL,
+                                                        &pgss_track_utility,
+                                                        true,
+                                                        PGC_SUSET,
+                                                        0,
+                                                        NULL,
+                                                        NULL);
+
        DefineCustomBoolVariable("pg_stat_statements.save",
                           "Save pg_stat_statements statistics across server shutdowns.",
                                                         NULL,
@@ -245,6 +260,8 @@ _PG_init(void)
        ExecutorRun_hook = pgss_ExecutorRun;
        prev_ExecutorEnd = ExecutorEnd_hook;
        ExecutorEnd_hook = pgss_ExecutorEnd;
+       prev_ProcessUtility = ProcessUtility_hook;
+       ProcessUtility_hook = pgss_ProcessUtility;
 }
 
 /*
@@ -254,10 +271,11 @@ void
 _PG_fini(void)
 {
        /* Uninstall hooks. */
+       shmem_startup_hook = prev_shmem_startup_hook;
        ExecutorStart_hook = prev_ExecutorStart;
        ExecutorRun_hook = prev_ExecutorRun;
        ExecutorEnd_hook = prev_ExecutorEnd;
-       shmem_startup_hook = prev_shmem_startup_hook;
+       ProcessUtility_hook = prev_ProcessUtility;
 }
 
 /*
@@ -539,7 +557,7 @@ pgss_ExecutorEnd(QueryDesc *queryDesc)
                InstrEndLoop(queryDesc->totaltime);
 
                pgss_store(queryDesc->sourceText,
-                                  queryDesc->totaltime,
+                                  queryDesc->totaltime->total,
                                   queryDesc->estate->es_processed);
        }
 
@@ -549,6 +567,61 @@ pgss_ExecutorEnd(QueryDesc *queryDesc)
                standard_ExecutorEnd(queryDesc);
 }
 
+/*
+ * ProcessUtility hook
+ */
+static void
+pgss_ProcessUtility(Node *parsetree, const char *queryString,
+                                       ParamListInfo params, bool isTopLevel,
+                                       DestReceiver *dest, char *completionTag)
+{
+       if (pgss_track_utility && pgss_enabled())
+       {
+               instr_time      start;
+               instr_time      duration;
+               uint64          rows = 0;
+
+               INSTR_TIME_SET_CURRENT(start);
+
+               nested_level++;
+               PG_TRY();
+               {
+                       if (prev_ProcessUtility)
+                               prev_ProcessUtility(parsetree, queryString, params,
+                                                                       isTopLevel, dest, completionTag);
+                       else
+                               standard_ProcessUtility(parsetree, queryString, params,
+                                                                               isTopLevel, dest, completionTag);
+                       nested_level--;
+               }
+               PG_CATCH();
+               {
+                       nested_level--;
+                       PG_RE_THROW();
+               }
+               PG_END_TRY();
+
+               INSTR_TIME_SET_CURRENT(duration);
+               INSTR_TIME_SUBTRACT(duration, start);
+
+               /* parse command tag to retrieve the number of affected rows. */
+               if (completionTag &&
+                       sscanf(completionTag, "COPY " UINT64_FORMAT, &rows) != 1)
+                       rows = 0;
+
+               pgss_store(queryString, INSTR_TIME_GET_DOUBLE(duration), rows);
+       }
+       else
+       {
+               if (prev_ProcessUtility)
+                       prev_ProcessUtility(parsetree, queryString, params,
+                                                               isTopLevel, dest, completionTag);
+               else
+                       standard_ProcessUtility(parsetree, queryString, params,
+                                                                       isTopLevel, dest, completionTag);
+       }
+}
+
 /*
  * Calculate hash value for a key
  */
@@ -587,7 +660,7 @@ pgss_match_fn(const void *key1, const void *key2, Size keysize)
  * Store some statistics for a statement.
  */
 static void
-pgss_store(const char *query, const Instrumentation *instr, uint32 rows)
+pgss_store(const char *query, double total_time, uint64 rows)
 {
        pgssHashKey key;
        double          usage;
@@ -631,7 +704,7 @@ pgss_store(const char *query, const Instrumentation *instr, uint32 rows)
 
                SpinLockAcquire(&e->mutex);
                e->counters.calls += 1;
-               e->counters.total_time += instr->total;
+               e->counters.total_time += total_time;
                e->counters.rows += rows;
                e->counters.usage += usage;
                SpinLockRelease(&e->mutex);

diff --git a/doc/src/sgml/pgstatstatements.sgml b/doc/src/sgml/pgstatstatements.sgml
index 7a98d3a07640ec30038d86b0a335270123bc9106..470902152fff437296726c76c29b702799ae212c 100644 (file)
--- a/doc/src/sgml/pgstatstatements.sgml
+++ b/doc/src/sgml/pgstatstatements.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/pgstatstatements.sgml,v 1.4 2009/12/01 02:31:11 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/pgstatstatements.sgml,v 1.5 2009/12/15 20:04:49 tgl Exp $ -->
 
 <sect1 id="pgstatstatements">
  <title>pg_stat_statements</title>
@@ -174,6 +174,23 @@
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <varname>pg_stat_statements.track_utility</varname> (<type>boolean</type>)
+    </term>
+
+    <listitem>
+     <para>
+      <varname>pg_stat_statements.track_utility</varname> controls whether
+      utility commands are tracked by the module.  Utility commands are
+      all those other than <command>SELECT</>, <command>INSERT</>,
+      <command>UPDATE</> and <command>DELETE</>.
+      The default value is <literal>on</>.
+      Only superusers can change this setting.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term>
      <varname>pg_stat_statements.save</varname> (<type>boolean</type>)

diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 2fd4b9923f5434d6713e213f02ecf7cbfd5e0e1b..10fb728fc792273a6428cb4c06b15a5f00ed4557 100644 (file)
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.323 2009/12/11 03:34:55 itagaki Exp $
+ *       $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.324 2009/12/15 20:04:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -58,6 +58,10 @@
 #include "utils/syscache.h"
 
 
+/* Hook for plugins to get control in ProcessUtility() */
+ProcessUtility_hook_type ProcessUtility_hook = NULL;
+
+
 /*
  * Verify user has ownership of specified relation, else ereport.
  *
@@ -274,6 +278,27 @@ ProcessUtility(Node *parsetree,
 {
        Assert(queryString != NULL);    /* required as of 8.4 */
 
+       /*
+        * We provide a function hook variable that lets loadable plugins
+        * get control when ProcessUtility is called.  Such a plugin would
+        * normally call standard_ProcessUtility().
+        */
+       if (ProcessUtility_hook)
+               (*ProcessUtility_hook) (parsetree, queryString, params,
+                                                               isTopLevel, dest, completionTag);
+       else
+               standard_ProcessUtility(parsetree, queryString, params,
+                                                               isTopLevel, dest, completionTag);
+}
+
+void
+standard_ProcessUtility(Node *parsetree,
+                                               const char *queryString,
+                                               ParamListInfo params,
+                                               bool isTopLevel,
+                                               DestReceiver *dest,
+                                               char *completionTag)
+{
        check_xact_readonly(parsetree);
 
        if (completionTag)

diff --git a/src/include/tcop/utility.h b/src/include/tcop/utility.h
index 271a97d690a7f3fe7c6c9ff44eebad813adbb6d8..8db35f6a01abf2331b5a8395ab544c7c26d824d5 100644 (file)
--- a/src/include/tcop/utility.h
+++ b/src/include/tcop/utility.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/tcop/utility.h,v 1.37 2009/12/01 02:31:13 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/tcop/utility.h,v 1.38 2009/12/15 20:04:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,9 +17,18 @@
 #include "tcop/tcopprot.h"
 
 
+/* Hook for plugins to get control in ProcessUtility() */
+typedef void (*ProcessUtility_hook_type) (Node *parsetree,
+                          const char *queryString, ParamListInfo params, bool isTopLevel,
+                          DestReceiver *dest, char *completionTag);
+extern PGDLLIMPORT ProcessUtility_hook_type ProcessUtility_hook;
+
 extern void ProcessUtility(Node *parsetree, const char *queryString,
                           ParamListInfo params, bool isTopLevel,
                           DestReceiver *dest, char *completionTag);
+extern void standard_ProcessUtility(Node *parsetree, const char *queryString,
+                          ParamListInfo params, bool isTopLevel,
+                          DestReceiver *dest, char *completionTag);
 
 extern bool UtilityReturnsTuples(Node *parsetree);