Show shared object statistics in pg_stat_database

This adds a row to the pg_stat_database view with datoid 0 and datname
NULL for those objects that are not in a database. This was added
particularly for checksums, but we were already tracking more satistics
for these objects, just not returning it.

Also add a checksum_last_failure column that holds the timestamptz of
the last checksum failure that occurred in a database (or in a
non-dataabase file), if any.

Author: Julien Rouhaud <rjuju123@gmail.com>

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 9cc332b6ad11c6246e1e9016ca302e5db6bdf4c9..547fe4cce934a9acebe723898ca706d766ecdee8 100644 (file)
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -2498,20 +2498,22 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
     <row>
      <entry><structfield>datid</structfield></entry>
      <entry><type>oid</type></entry>
-     <entry>OID of a database</entry>
+     <entry>OID of this database, or 0 for objects belonging to a shared
+     relation</entry>
     </row>
     <row>
      <entry><structfield>datname</structfield></entry>
      <entry><type>name</type></entry>
-     <entry>Name of this database</entry>
+     <entry>Name of this database, or <literal>NULL</literal> for the shared
+     objects.</entry>
     </row>
     <row>
      <entry><structfield>numbackends</structfield></entry>
      <entry><type>integer</type></entry>
-     <entry>Number of backends currently connected to this database.
-     This is the only column in this view that returns a value reflecting
-     current state; all other columns return the accumulated values since
-     the last reset.</entry>
+     <entry>Number of backends currently connected to this database, or
+     <literal>NULL</literal> for the shared objects.  This is the only column
+     in this view that returns a value reflecting current state; all other
+     columns return the accumulated values since the last reset.</entry>
     </row>
     <row>
      <entry><structfield>xact_commit</structfield></entry>
@@ -2597,7 +2599,14 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
     <row>
      <entry><structfield>checksum_failures</structfield></entry>
      <entry><type>bigint</type></entry>
-     <entry>Number of data page checksum failures detected in this database</entry>
+     <entry>Number of data page checksum failures detected in this
+     database</entry>
+    </row>
+    <row>
+     <entry><structfield>checksum_last_failure</structfield></entry>
+     <entry><type>timestamp with time zone</type></entry>
+     <entry>Time at which the last data page checksum failure was detected in
+     this database, or on a shared object.</entry>
     </row>
     <row>
      <entry><structfield>blk_read_time</structfield></entry>
@@ -2622,7 +2631,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
 
   <para>
    The <structname>pg_stat_database</structname> view will contain one row
-   for each database in the cluster, showing database-wide statistics.
+   for each database in the cluster, plus one for the shared objects, showing
+   database-wide statistics.
   </para>
 
   <table id="pg-stat-database-conflicts-view" xreflabel="pg_stat_database_conflicts">

diff --git a/doc/src/sgml/ref/initdb.sgml b/doc/src/sgml/ref/initdb.sgml
index 7f323103084b056f0e819e4e9d8d9a4103eca244..7fc3152c6d3c83418c29aebe7aeba07afa7076e3 100644 (file)
--- a/doc/src/sgml/ref/initdb.sgml
+++ b/doc/src/sgml/ref/initdb.sgml
@@ -218,7 +218,9 @@ PostgreSQL documentation
         I/O system that would otherwise be silent. Enabling checksums
         may incur a noticeable performance penalty. This option can only
         be set during initialization, and cannot be changed later. If
-        set, checksums are calculated for all objects, in all databases.
+        set, checksums are calculated for all objects, in all databases. All
+        checksum failures will be reported in the <xref
+        linkend="pg-stat-database-view"/> view.
        </para>
       </listitem>
      </varlistentry>

diff --git a/doc/src/sgml/ref/pg_basebackup.sgml b/doc/src/sgml/ref/pg_basebackup.sgml
index 830e87fc6ae7020c926020abbe003a98961a4c55..fc9e222f8d0b8dec3cdf9c747d1b6c0ec097415e 100644 (file)
--- a/doc/src/sgml/ref/pg_basebackup.sgml
+++ b/doc/src/sgml/ref/pg_basebackup.sgml
@@ -531,7 +531,8 @@ PostgreSQL documentation
         By default, checksums are verified and checksum failures will result
         in a non-zero exit status. However, the base backup will not be
         removed in such a case, as if the <option>--no-clean</option> option
-        had been used.
+        had been used.  Checksum verifications failures will also be reported
+        in the <xref linkend="pg-stat-database-view"/> view.
        </para>
       </listitem>
      </varlistentry>

diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 22cbb0e51fa41acea75c1e42779b91dee4bb11c7..161bad6c900f1877aa8f4742797e1607c93ba9df 100644 (file)
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -816,7 +816,10 @@ CREATE VIEW pg_stat_database AS
     SELECT
             D.oid AS datid,
             D.datname AS datname,
-            pg_stat_get_db_numbackends(D.oid) AS numbackends,
+                CASE
+                    WHEN (D.oid = (0)::oid) THEN NULL::integer
+                    ELSE pg_stat_get_db_numbackends(D.oid)
+                END AS numbackends,
             pg_stat_get_db_xact_commit(D.oid) AS xact_commit,
             pg_stat_get_db_xact_rollback(D.oid) AS xact_rollback,
             pg_stat_get_db_blocks_fetched(D.oid) -
@@ -832,10 +835,15 @@ CREATE VIEW pg_stat_database AS
             pg_stat_get_db_temp_bytes(D.oid) AS temp_bytes,
             pg_stat_get_db_deadlocks(D.oid) AS deadlocks,
             pg_stat_get_db_checksum_failures(D.oid) AS checksum_failures,
+            pg_stat_get_db_checksum_last_failure(D.oid) AS checksum_last_failure,
             pg_stat_get_db_blk_read_time(D.oid) AS blk_read_time,
             pg_stat_get_db_blk_write_time(D.oid) AS blk_write_time,
             pg_stat_get_db_stat_reset_time(D.oid) AS stats_reset
-    FROM pg_database D;
+    FROM (
+        SELECT 0 AS oid, NULL::name AS datname
+        UNION ALL
+        SELECT oid, datname FROM pg_database
+    ) D;
 
 CREATE VIEW pg_stat_database_conflicts AS
     SELECT

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 7c0b24a16fa6b15dcae035677ea2e9ec3154f84e..cdf87bae327e704ee030ece4041ab9db49f176b7 100644 (file)
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -1523,7 +1523,7 @@ pgstat_report_deadlock(void)
 
 
 /* --------
- * pgstat_report_checksum_failures_in_db(dboid, failure_count) -
+ * pgstat_report_checksum_failures_in_db() -
  *
  *     Tell the collector about one or more checksum failures.
  * --------
@@ -1539,6 +1539,8 @@ pgstat_report_checksum_failures_in_db(Oid dboid, int failurecount)
        pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_CHECKSUMFAILURE);
        msg.m_databaseid = dboid;
        msg.m_failurecount = failurecount;
+       msg.m_failure_time = GetCurrentTimestamp();
+
        pgstat_send(&msg, sizeof(msg));
 }
 
@@ -4651,6 +4653,7 @@ reset_dbentry_counters(PgStat_StatDBEntry *dbentry)
        dbentry->n_temp_bytes = 0;
        dbentry->n_deadlocks = 0;
        dbentry->n_checksum_failures = 0;
+       dbentry->last_checksum_failure = 0;
        dbentry->n_block_read_time = 0;
        dbentry->n_block_write_time = 0;
 
@@ -6307,6 +6310,7 @@ pgstat_recv_checksum_failure(PgStat_MsgChecksumFailure *msg, int len)
        dbentry = pgstat_get_db_entry(msg->m_databaseid, true);
 
        dbentry->n_checksum_failures += msg->m_failurecount;
+       dbentry->last_checksum_failure = msg->m_failure_time;
 }
 
 /* ----------

diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index 537f09e34299f77a3190e584ed2c370483688d25..36dcb2875408304c7b86fed2348a181d7518c53b 100644 (file)
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1584,9 +1584,9 @@ sendFile(const char *readfilename, const char *tarfilename, struct stat *statbuf
                                (errmsg("file \"%s\" has a total of %d checksum verification "
                                                "failures", readfilename, checksum_failures)));
 
-               if (dboid != InvalidOid)
-                       pgstat_report_checksum_failures_in_db(dboid, checksum_failures);
+               pgstat_report_checksum_failures_in_db(dboid, checksum_failures);
        }
+
        total_checksum_failures += checksum_failures;
 
        return true;

diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 9a1d07bee3304c9f80abdeb31379ba40005a2842..97f41fb46c171c1019bfaa309c9f5600a7803810 100644 (file)
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1534,6 +1534,24 @@ pg_stat_get_db_checksum_failures(PG_FUNCTION_ARGS)
        PG_RETURN_INT64(result);
 }
 
+Datum
+pg_stat_get_db_checksum_last_failure(PG_FUNCTION_ARGS)
+{
+       Oid                     dbid = PG_GETARG_OID(0);
+       TimestampTz result;
+       PgStat_StatDBEntry *dbentry;
+
+       if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
+               result = 0;
+       else
+               result = dbentry->last_checksum_failure;
+
+       if (result == 0)
+               PG_RETURN_NULL();
+       else
+               PG_RETURN_TIMESTAMPTZ(result);
+}
+
 Datum
 pg_stat_get_db_blk_read_time(PG_FUNCTION_ARGS)
 {

diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index ad4519e0011c847bfca1239d1ebbf0e4d6d89000..73ebfdf970967ed7486234116b0250841347815a 100644 (file)
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5285,6 +5285,11 @@
   proname => 'pg_stat_get_db_checksum_failures', provolatile => 's',
   proparallel => 'r', prorettype => 'int8', proargtypes => 'oid',
   prosrc => 'pg_stat_get_db_checksum_failures' },
+{ oid => '8394',
+  descr => 'statistics: when last checksum failure was detected in database',
+  proname => 'pg_stat_get_db_checksum_last_failure', provolatile => 's',
+  proparallel => 'r', prorettype => 'timestamptz', proargtypes => 'oid',
+  prosrc => 'pg_stat_get_db_checksum_last_failure' },
 { oid => '3074', descr => 'statistics: last reset for a database',
   proname => 'pg_stat_get_db_stat_reset_time', provolatile => 's',
   proparallel => 'r', prorettype => 'timestamptz', proargtypes => 'oid',

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index a68927b57a28a865a5ff6aae657a8e17c2b87603..fa5dca3b87edd33865bbb51ad064f0c698d31dfa 100644 (file)
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -541,6 +541,7 @@ typedef struct PgStat_MsgChecksumFailure
        PgStat_MsgHdr m_hdr;
        Oid                     m_databaseid;
        int                     m_failurecount;
+       TimestampTz     m_failure_time;
 } PgStat_MsgChecksumFailure;
 
 
@@ -607,6 +608,7 @@ typedef struct PgStat_StatDBEntry
        PgStat_Counter n_temp_bytes;
        PgStat_Counter n_deadlocks;
        PgStat_Counter n_checksum_failures;
+       TimestampTz last_checksum_failure;
        PgStat_Counter n_block_read_time;       /* times in microseconds */
        PgStat_Counter n_block_write_time;
 

diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 2f048f3bdc0cd5d53be4a1770cac4166a73eb59b..30973904c55482d896b016143e6f3f1b60a9e485 100644 (file)
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1805,7 +1805,10 @@ pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_timed_checkpoints() AS checkpoints
     pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 pg_stat_database| SELECT d.oid AS datid,
     d.datname,
-    pg_stat_get_db_numbackends(d.oid) AS numbackends,
+        CASE
+            WHEN (d.oid = (0)::oid) THEN NULL::integer
+            ELSE pg_stat_get_db_numbackends(d.oid)
+        END AS numbackends,
     pg_stat_get_db_xact_commit(d.oid) AS xact_commit,
     pg_stat_get_db_xact_rollback(d.oid) AS xact_rollback,
     (pg_stat_get_db_blocks_fetched(d.oid) - pg_stat_get_db_blocks_hit(d.oid)) AS blks_read,
@@ -1820,10 +1823,16 @@ pg_stat_database| SELECT d.oid AS datid,
     pg_stat_get_db_temp_bytes(d.oid) AS temp_bytes,
     pg_stat_get_db_deadlocks(d.oid) AS deadlocks,
     pg_stat_get_db_checksum_failures(d.oid) AS checksum_failures,
+    pg_stat_get_db_checksum_last_failure(d.oid) AS checksum_last_failure,
     pg_stat_get_db_blk_read_time(d.oid) AS blk_read_time,
     pg_stat_get_db_blk_write_time(d.oid) AS blk_write_time,
     pg_stat_get_db_stat_reset_time(d.oid) AS stats_reset
-   FROM pg_database d;
+   FROM ( SELECT 0 AS oid,
+            NULL::name AS datname
+        UNION ALL
+         SELECT pg_database.oid,
+            pg_database.datname
+           FROM pg_database) d;
 pg_stat_database_conflicts| SELECT d.oid AS datid,
     d.datname,
     pg_stat_get_db_conflict_tablespace(d.oid) AS confl_tablespace,