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Postgres FD Implementation
Commit aebe9894 authored by Tom Lane's avatar Tom Lane
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Make a copy-editing pass over the new documentation for statistics views. 

Fix a bunch of typos, improve markup, make wording more uniform, rearrange
some material.  No substantive changes.
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doc/src/sgml/monitoring.sgml
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......@@ -140,13 +140,13 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
</para>
<para>
The parameter <xref linkend="guc-track-counts"> controls whether
statistics are collected about table and index accesses.
The parameter <xref linkend="guc-track-activities"> enables monitoring
of the current command being executed by any server process.
</para>
<para>
The parameter <xref linkend="guc-track-iotiming"> enables monitoring
of block read and write times.
The parameter <xref linkend="guc-track-counts"> controls whether
statistics are collected about table and index accesses.
</para>
<para>
......@@ -155,8 +155,8 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
</para>
<para>
The parameter <xref linkend="guc-track-activities"> enables monitoring
of the current command being executed by any server process.
The parameter <xref linkend="guc-track-iotiming"> enables monitoring
of block read and write times.
</para>
<para>
......@@ -170,13 +170,16 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
</para>
<para>
The statistics collector transmits the collected
information to backends (including autovacuum) through temporary files.
These files are stored in the <filename>pg_stat_tmp</filename> subdirectory.
When the postmaster shuts down, a permanent copy of the statistics
data is stored in the <filename>global</filename> subdirectory. For increased
performance, the parameter <xref linkend="guc-stats-temp-directory"> can
be pointed at a RAM-based file system, decreasing physical I/O requirements.
The statistics collector transmits the collected information to other
<productname>PostgreSQL</productname> processes through temporary files.
These files are stored in the directory named by the
<xref linkend="guc-stats-temp-directory"> parameter,
<filename>pg_stat_tmp</filename> by default.
For better performance, <varname>stats_temp_directory</> can be
pointed at a RAM-based file system, decreasing physical I/O requirements.
When the server shuts down, a permanent copy of the statistics
data is stored in the <filename>global</filename> subdirectory, so that
statistics can be retained across server restarts.
</para>
</sect2>
......@@ -188,7 +191,8 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
Several predefined views, listed in <xref
linkend="monitoring-stats-views-table">, are available to show the results
of statistics collection. Alternatively, one can
build custom views using the underlying statistics functions.
build custom views using the underlying statistics functions, as discussed
in <xref linkend="monitoring-stats-functions">.
</para>
<para>
......@@ -198,7 +202,7 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
the collector just before going idle; so a query or transaction still in
progress does not affect the displayed totals. Also, the collector itself
emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname>
milliseconds (500 unless altered while building the server). So the
milliseconds (500 msec unless altered while building the server). So the
displayed information lags behind actual activity. However, current-query
information collected by <varname>track_activities</varname> is
always up-to-date.
......@@ -229,10 +233,8 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
collector) in the views <structname>pg_stat_xact_all_tables</>,
<structname>pg_stat_xact_sys_tables</>,
<structname>pg_stat_xact_user_tables</>, and
<structname>pg_stat_xact_user_functions</>, or via these views' underlying
functions (named the same as the standard statistics functions but with the
prefix <function>pg_stat_get_xact_</function>). These numbers do not act
as stated above; instead they update continuously throughout the transaction.
<structname>pg_stat_xact_user_functions</>. These numbers do not act as
stated above; instead they update continuously throughout the transaction.
</para>
<table id="monitoring-stats-views-table">
......@@ -253,58 +255,33 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
<indexterm><primary>pg_stat_activity</primary></indexterm>
</entry>
<entry>
<para>One row per server process, showing information related to
each connection to the server. Unless the
<xref linkend="guc-track-activities"> parameter has been turned
off, it is possible to monitor state and query information of
all running processes.
</para>
<para>
See <xref linkend="pg-stat-activity-view"> for more details.
</para>
</entry>
One row per server process, showing information related to
the current activity of that process, such as state and current query.
See <xref linkend="pg-stat-activity-view"> for details.
</entry>
</row>
<row>
<entry><structname>pg_stat_bgwriter</><indexterm><primary>pg_stat_bgwriter</primary></indexterm></entry>
<entry>One row only, showing cluster-wide statistics. See
<xref linkend="pg-stat-bgwriter-view"> for more details.
<entry>One row only, showing statistics about the
background writer process's activity. See
<xref linkend="pg-stat-bgwriter-view"> for details.
</entry>
</row>
<row>
<entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
<entry>One row per database, showing database-wide statistics. See
<xref linkend="pg-stat-database-view"> for more details.
<xref linkend="pg-stat-database-view"> for details.
</entry>
</row>
<row>
<entry><structname>pg_stat_database_conflicts</><indexterm><primary>pg_stat_database_conflicts</primary></indexterm></entry>
<entry>
One row per database showing database-wide statistics about
query cancels due to conflict with recovery on standby servers.
Will only contain information on standby servers, since
conflicts do not occur on master servers.
See <xref linkend="pg-stat-database-conflicts-view"> for more details.
</entry>
</row>
<row>
<entry><structname>pg_stat_replication</><indexterm><primary>pg_stat_replication</primary></indexterm></entry>
<entry>One row per WAL sender process, showing statistics about the
replication to this slave. See <xref linkend="pg-stat-replication-view">
for more details. Only directly connected standbys are listed; no
information about downstream standby servers is recorded.
</entry>
</row>
<row>
<entry><structname>pg_stat_all_tables</><indexterm><primary>pg_stat_all_tables</primary></indexterm></entry>
<entry>
One row for each table in the current database (including TOAST
tables) with information about accesses to this specific table.
See <xref linkend="pg-stat-all-tables-view"> for more details.
One row for each table in the current database, showing statistics
about accesses to that specific table.
See <xref linkend="pg-stat-all-tables-view"> for details.
</entry>
</row>
......@@ -344,9 +321,9 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
<row>
<entry><structname>pg_stat_all_indexes</><indexterm><primary>pg_stat_all_indexes</primary></indexterm></entry>
<entry>
One row for each index in the current database with information
about accesses to this specific index.
See <xref linkend="pg-stat-all-indexes-view"> for more details.
One row for each index in the current database, showing statistics
about accesses to that specific index.
See <xref linkend="pg-stat-all-indexes-view"> for details.
</entry>
</row>
......@@ -365,9 +342,9 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
<row>
<entry><structname>pg_statio_all_tables</><indexterm><primary>pg_statio_all_tables</primary></indexterm></entry>
<entry>
One row for each table in the current database (including TOAST
tables) with information about I/O on this specific table.
See <xref linkend="pg-statio-all-tables-view"> for more details.
One row for each table in the current database, showing statistics
about I/O on that specific table.
See <xref linkend="pg-statio-all-tables-view"> for details.
</entry>
</row>
......@@ -386,9 +363,9 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
<row>
<entry><structname>pg_statio_all_indexes</><indexterm><primary>pg_statio_all_indexes</primary></indexterm></entry>
<entry>
One row for each index in the current database
with information about I/O on this specific index.
See <xref linkend="pg-statio-all-indexes-view"> for more details.
One row for each index in the current database,
showing statistics about I/O on that specific index.
See <xref linkend="pg-statio-all-indexes-view"> for details.
</entry>
</row>
......@@ -407,9 +384,9 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
<row>
<entry><structname>pg_statio_all_sequences</><indexterm><primary>pg_statio_all_sequences</primary></indexterm></entry>
<entry>
One row for each sequence in the current database
with information about I/O on this specific sequence.
See <xref linkend="pg-statio-all-sequences-view"> for more details.
One row for each sequence in the current database,
showing statistics about I/O on that specific sequence.
See <xref linkend="pg-statio-all-sequences-view"> for details.
</entry>
</row>
......@@ -429,9 +406,9 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
<row>
<entry><structname>pg_stat_user_functions</><indexterm><primary>pg_stat_user_functions</primary></indexterm></entry>
<entry>
One row for each tracked function (as specified by the
<xref linkend="guc-track-functions"> parameter). See
<xref linkend="pg-stat-user-functions-view"> for more details.
One row for each tracked function, showing statistics
about executions of that function. See
<xref linkend="pg-stat-user-functions-view"> for details.
</entry>
</row>
......@@ -442,6 +419,23 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
yet included in <structname>pg_stat_user_functions</>).</entry>
</row>
<row>
<entry><structname>pg_stat_replication</><indexterm><primary>pg_stat_replication</primary></indexterm></entry>
<entry>One row per WAL sender process, showing statistics about
replication to that sender's connected standby server.
See <xref linkend="pg-stat-replication-view"> for details.
</entry>
</row>
<row>
<entry><structname>pg_stat_database_conflicts</><indexterm><primary>pg_stat_database_conflicts</primary></indexterm></entry>
<entry>
One row per database, showing database-wide statistics about
query cancels due to conflict with recovery on standby servers.
See <xref linkend="pg-stat-database-conflicts-view"> for details.
</entry>
</row>
</tbody>
</tgroup>
</table>
......@@ -451,33 +445,6 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
indexes are being used and how effective they are.
</para>
<para>
Indexes can be
used either directly or via <quote>bitmap scans</>. In a bitmap scan
the output of several indexes can be combined via AND or OR rules;
so it is difficult to associate individual heap row fetches
with specific indexes when a bitmap scan is used. Therefore, a bitmap
scan increments the
<structname>pg_stat_all_indexes</>.<structfield>idx_tup_read</>
count(s) for the index(es) it uses, and it increments the
<structname>pg_stat_all_tables</>.<structfield>idx_tup_fetch</>
count for the table, but it does not affect
<structname>pg_stat_all_indexes</>.<structfield>idx_tup_fetch</>.
</para>
<note>
<para>
Before <productname>PostgreSQL</productname> 8.1, the
<structfield>idx_tup_read</> and <structfield>idx_tup_fetch</> counts
were essentially always equal. Now they can be different even without
considering bitmap scans, because <structfield>idx_tup_read</> counts
index entries retrieved from the index while <structfield>idx_tup_fetch</>
counts live rows fetched from the table; the latter will be less if any
dead or not-yet-committed rows are fetched using the index, or if any
heap fetches are avoided by means of an index-only scan.
</para>
</note>
<para>
The <structname>pg_statio_</> views are primarily useful to
determine the effectiveness of the buffer cache. When the number
......@@ -495,21 +462,6 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
into the kernel's handling of I/O.
</para>
<para>
Other ways of looking at the statistics can be set up by writing
queries that use the same underlying statistics access functions as
these standard views do. These functions are listed in <xref
linkend="monitoring-stats-funcs-table">. The per-database access
functions take a database OID as an argument to identify which
database to report on. The per-table and per-index functions take
a table or index OID. The functions for function-call statistics
take a function OID. (Note that only tables, indexes, and functions
in the current database can be seen with these functions.) The
per-server-process access functions take a server process
number, which ranges from one to the number of currently active
server processes.
</para>
<table id="pg-stat-activity-view" xreflabel="pg_stat_activity">
<title>pg_stat_activity view</title>
......@@ -525,98 +477,94 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
<tbody>
<row>
<entry>datid</entry>
<entry><structfield>datid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the database the backend is connected to.
<entry>OID of the database this backend is connected to.
This value can also be returned by directly calling
the <function>pg_stat_get_backend_dbid</function> function.</entry>
</row>
<row>
<entry>datname</entry>
<entry><structfield>datname</></entry>
<entry><type>name</></entry>
<entry>The name of the database the backend is connected to.</entry>
<entry>Name of the database this backend is connected to</entry>
</row>
<row>
<entry>pid</entry>
<entry><structfield>pid</></entry>
<entry><type>integer</></entry>
<entry>The process ID of the backend.
<entry>Process ID of this backend.
This value can also be returned by directly calling
the <function>pg_stat_get_backend_pid</function>.</entry>
</row>
<row>
<entry>usesysid</entry>
<entry><structfield>usesysid</></entry>
<entry><type>oid</></entry>
<entry>The id of the user logged into the backend.
<entry>OID of the user logged into this backend.
This value can also be returned by directly calling
the <function>pg_stat_get_backend_userid</function>.</entry>
</row>
<row>
<entry>usename</entry>
<entry><structfield>usename</></entry>
<entry><type>name</></entry>
<entry>The name of the user logged into the backend.</entry>
<entry>Name of the user logged into this backend</entry>
</row>
<row>
<entry>application_name</entry>
<entry><structfield>application_name</></entry>
<entry><type>text</></entry>
<entry>The name of the application that has initiated the connection
to the backend.</entry>
<entry>Name of the application that is connected
to this backend</entry>
</row>
<row>
<entry>client_addr</entry>
<entry><structfield>client_addr</></entry>
<entry><type>inet</></entry>
<entry>The remote IP of the client connected to the backend.
If this field is not set, it indicates that the client is either connected
via a Unix socket on the server machine or is an internal process such
as autovacuum.
<entry>IP address of the client connected to this backend.
If this field is not set, it indicates either that the client is
connected via a Unix socket on the server machine or that this is an
internal process such as autovacuum.
This value can also be returned by directly calling
the <function>pg_stat_get_backend_client_addr</function>.
</entry>
</row>
<row>
<entry>client_hostname</entry>
<entry><structfield>client_hostname</></entry>
<entry><type>text</></entry>
<entry>
If available, the hostname of the client as reported by a
reverse lookup of <structfield>client_addr</>. This field will
only be set when <xref linkend="guc-log-hostname"> is enabled.
<entry>Host name of the connected client, as reported by a
reverse DNS lookup of <structfield>client_addr</>. This field will
only be set for IP connections, and only when <xref
linkend="guc-log-hostname"> is enabled.
</entry>
</row>
<row>
<entry>client_port</entry>
<entry><structfield>client_port</></entry>
<entry><type>integer</></entry>
<entry>
The remote TCP port that the client is using for communication
to the backend, or <symbol>NULL</> if a unix socket is used.
<entry>TCP port number that the client is using for communication
with the backend, or <symbol>NULL</> if a Unix socket is used.
This value can also be returned by directly calling
the <function>pg_stat_get_backend_client_port</function>.
</entry>
</row>
<row>
<entry>backend_start</entry>
<entry><structfield>backend_start</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>
The time when this process was started, i.e. when the
<entry>Time when this process was started, i.e., when the
client connected to the server.
This value can also be returned by directly calling
the <function>pg_stat_get_backend_start</function>.
</entry>
</row>
<row>
<entry>xact_start</entry>
<entry><structfield>xact_start</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>
The time when the current transaction was started. If the client is
using autocommit for transactions, this value is equal to the
query_start column.
<entry>Time when the current transaction was started. If the current
query is the first of its transaction, this value is equal to the
<structfield>query_start</> column.
This value can also be returned by directly calling
the <function>pg_stat_get_backend_xact_start</function>.
</entry>
</row>
<row>
<entry>query_start</entry>
<entry><structfield>query_start</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>
The time when the currently active query started, or if
<entry>Time when the currently active query was started, or if
<structfield>state</> is <literal>idle</>, when the last query
was started.
This value can also be returned by directly calling
......@@ -624,98 +572,69 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
</entry>
</row>
<row>
<entry>state_change</entry>
<entry><structfield>state_change</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>The time when the <structfield>state</> was last changed.</entry>
<entry>Time when the <structfield>state</> was last changed</entry>
</row>
<row>
<entry>waiting</entry>
<entry><structfield>waiting</></entry>
<entry><type>boolean</></entry>
<entry>
Boolean indicating if a backend is currently waiting on a lock.
<entry>True if the backend is currently waiting on a lock.
This value can also be returned by directly calling
the <function>pg_stat_get_backend_waiting</function>.
</entry>
</row>
<row>
<entry>state</entry>
<entry><structfield>state</></entry>
<entry><type>text</></entry>
<entry>
The <structfield>state</> of the currently running query.
Can be one of:
<variablelist>
<varlistentry>
<term>active</term>
<listitem>
<para>
The backend is executing a query.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>idle</term>
<listitem>
<para>
There is no query executing in the backend.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>idle in transaction</term>
<listitem>
<para>
The backend is in a transaction, but is currently not currently
executing a query.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>idle in transaction (aborted)</term>
<listitem>
<para>
This state is similar to <literal>idle in transaction</>,
except one of the statements in the transaction caused an error.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>fastpath function call</term>
<listitem>
<para>
The backend is executing a fast-path function.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>disabled</term>
<listitem>
<para>
This state indicates that <xref linkend="guc-track-activities">
is disabled.
</para>
</listitem>
</varlistentry>
</variablelist>
<note>
<para>
The <structfield>waiting</> and <structfield>state</> columns are
independent. If a query is in the <literal>active</> state,
it may or may not be <literal>waiting</>. If a query is
<literal>active</> and <structfield>waiting</> is true, it means
that the query is being executed, but is being blocked by a lock
somewhere in the system.
</para>
</note>
<entry>Current overall state of this backend.
Possible values are:
<itemizedlist>
<listitem>
<para>
<literal>active</>: The backend is executing a query.
</para>
</listitem>
<listitem>
<para>
<literal>idle</>: The backend is waiting for a new client command.
</para>
</listitem>
<listitem>
<para>
<literal>idle in transaction</>: The backend is in a transaction,
but is not currently executing a query.
</para>
</listitem>
<listitem>
<para>
<literal>idle in transaction (aborted)</>: This state is similar to
<literal>idle in transaction</>, except one of the statements in
the transaction caused an error.
</para>
</listitem>
<listitem>
<para>
<literal>fastpath function call</>: The backend is executing a
fast-path function.
</para>
</listitem>
<listitem>
<para>
<literal>disabled</>: This state is reported if <xref
linkend="guc-track-activities"> is disabled in this backend.
</para>
</listitem>
</itemizedlist>
</entry>
</row>
<row>
<entry>query</entry>
<entry><structfield>query</></entry>
<entry><type>text</></entry>
<entry>
The most recent query that the backend has executed. If
<structfield>state</> is <literal>active</> this means the currently
executing query. In all other states, it means the last query that was
executed.
<entry>Text of the backend's most recent query. If
<structfield>state</> is <literal>active</> this field shows the
currently executing query. In all other states, it shows the last query
that was executed.
</entry>
</row>
</tbody>
......@@ -724,21 +643,20 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
<para>
The <structname>pg_stat_activity</structname> view will have one row
per server process, showing information related to each connection to
the server.
per server process, showing information related to
the current activity of that process.
</para>
<para>
All functions used in the view are indexed by backend id number. The
function <function>pg_stat_get_backend_idset</function> provides a
convenient way to generate one row for each active server process. For
example, to show the <acronym>PID</>s and current queries of all server processes:
<programlisting>
SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
pg_stat_get_backend_activity(s.backendid) AS query
FROM (SELECT pg_stat_get_backend_idset() AS backendid) AS s;
</programlisting>
</para>
<note>
<para>
The <structfield>waiting</> and <structfield>state</> columns are
independent. If a backend is in the <literal>active</> state,
it may or may not be <literal>waiting</>. If the state is
<literal>active</> and <structfield>waiting</> is true, it means
that a query is being executed, but is being blocked by a lock
somewhere in the system.
</para>
</note>
<table id="pg-stat-bgwriter-view" xreflabel="pg_stat_bgwriter">
<title>pg_stat_bgwriter view</title>
......@@ -754,21 +672,21 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<tbody>
<row>
<entry>checkpoints_timed</entry>
<entry><structfield>checkpoints_timed</></entry>
<entry><type>bigint</type></entry>
<entry>Number of scheduled checkpoints.
<entry>Number of scheduled checkpoints that have been performed.
This value can also be returned by directly calling
the <function>pg_stat_get_bgwriter_timed_checkpoints</function> function.</entry>
</row>
<row>
<entry>checkpoints_requested</entry>
<entry><structfield>checkpoints_req</></entry>
<entry><type>bigint</type></entry>
<entry>Number of requested checkpoints.
<entry>Number of requested checkpoints that have been performed.
This value can also be returned by directly calling
the <function>pg_stat_get_bgwriter_requested_checkpoints</function> function.</entry>
</row>
<row>
<entry>checkpoint_write_time</entry>
<entry><structfield>checkpoint_write_time</></entry>
<entry><type>bigint</type></entry>
<entry>
Total amount of time that has been spent in the portion of
......@@ -779,7 +697,7 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
</entry>
</row>
<row>
<entry>checkpoint_sync_time</entry>
<entry><structfield>checkpoint_sync_time</></entry>
<entry><type>bigint</type></entry>
<entry>
Total amount of time that has been spent in the portion of
......@@ -790,21 +708,21 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
</entry>
</row>
<row>
<entry>buffers_checkpoint</entry>
<entry><structfield>buffers_checkpoint</></entry>
<entry><type>bigint</type></entry>
<entry>Number of buffers written during checkpoints.
This value can also be returned by directly calling
the <function>pg_stat_get_bgwriter_buf_written_checkpoints</function> function.</entry>
</row>
<row>
<entry>buffers_clean</entry>
<entry><structfield>buffers_clean</></entry>
<entry><type>bigint</type></entry>
<entry>Number of buffers written by the background writer.
This value can also be returned by directly calling
the <function>pg_stat_get_bgwriter_buf_written_clean</function> function.</entry>
</row>
<row>
<entry>maxwritten_clean</entry>
<entry><structfield>maxwritten_clean</></entry>
<entry><type>bigint</type></entry>
<entry>Number of times the background writer stopped a cleaning
scan because it had written too many buffers.
......@@ -812,30 +730,30 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
the <function>pg_stat_get_bgwriter_maxwritten_clean</function> function.</entry>
</row>
<row>
<entry>buffers_backend</entry>
<entry><structfield>buffers_backend</></entry>
<entry><type>bigint</type></entry>
<entry>Number of buffers written directly by a backend.
This value can also be returned by directly calling
the <function>pg_stat_get_buf_written_backend</function> function.</entry>
</row>
<row>
<entry>buffers_backend_fsync</entry>
<entry><structfield>buffers_backend_fsync</></entry>
<entry><type>bigint</type></entry>
<entry>Number of times a backend had to execute its own fsync
call (normally the background writer handles those even when the
backend does its own write)</entry>
<entry>Number of times a backend had to execute its own
<function>fsync</> call (normally the background writer handles those
even when the backend does its own write)</entry>
</row>
<row>
<entry>buffers_alloc</entry>
<entry><structfield>buffers_alloc</></entry>
<entry><type>bigint</type></entry>
<entry>Number of buffers allocated.
This value can also be returned by directly calling
the <function>pg_stat_get_buf_alloc</function> function.</entry>
</row>
<row>
<entry>stats_reset</entry>
<entry><type>bigint</type></entry>
<entry>The last time these statistics were reset.
<entry><structfield>stats_reset</></entry>
<entry><type>timestamp with time zone</type></entry>
<entry>Time at which these statistics were last reset.
This value can also be returned by directly calling
the <function>pg_stat_get_bgwriter_stat_reset_time</function> function.</entry>
</row>
......@@ -845,7 +763,7 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<para>
The <structname>pg_stat_bgwriter</structname> view will always have a
single row with global data for the cluster.
single row, containing global data for the cluster.
</para>
<table id="pg-stat-database-view" xreflabel="pg_stat_database">
......@@ -861,151 +779,150 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<tbody>
<row>
<entry>datid</entry>
<entry><structfield>datid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the database</entry>
<entry>OID of a database</entry>
</row>
<row>
<entry>datname</entry>
<entry><structfield>datname</></entry>
<entry><type>name</></entry>
<entry>The name of the database</entry>
<entry>Name of this database</entry>
</row>
<row>
<entry>numbackends</entry>
<entry><structfield>numbackends</></entry>
<entry><type>integer</></entry>
<entry>The number of backends currently connected to this database.
This is the only column in this view that returns a value for the
current state, all other columns return the accumulated values since
<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. This value can also be returned by directly calling
the <function>pg_stat_get_db_numbackends</function> function.</entry>
</row>
<row>
<entry>xact_commit</entry>
<entry><structfield>xact_commit</></entry>
<entry><type>bigint</></entry>
<entry>The number of transactions in this database that have been
<entry>Number of transactions in this database that have been
committed. This value can also be returned by directly calling
the <function>pg_stat_get_db_xact_commit</function> function.</entry>
</row>
<row>
<entry>xact_rollback</entry>
<entry><structfield>xact_rollback</></entry>
<entry><type>bigint</></entry>
<entry>The number of transactions in this database that have been
<entry>Number of transactions in this database that have been
rolled back. This value can also be returned by directly calling
the <function>pg_stat_get_db_xact_rollback</function> function.</entry>
</row>
<row>
<entry>blks_read</entry>
<entry><structfield>blks_read</></entry>
<entry><type>bigint</></entry>
<entry>The number of disk blocks read in this database.
<entry>Number of disk blocks read in this database.
This value can also be returned by directly calling
the <function>pg_stat_get_db_blocks_fetched</function> and
<function>pg_stat_get_db_blocks_hit</function> functions and
subtracting the results.</entry>
</row>
<row>
<entry>blks_hits</entry>
<entry><structfield>blks_hit</></entry>
<entry><type>bigint</></entry>
<entry>The number of disk blocks read from the buffer cache
(this only includes hits in the PostgreSQL buffer cache, and not
the operating system filesystem cache).
<entry>Number of times disk blocks were found already in the buffer
cache, so that a read was not necessary (this only includes hits in the
PostgreSQL buffer cache, not the operating system's filesystem cache).
This value can also be returned by directly calling
the <function>pg_stat_get_db_blocks_hit</function> function.</entry>
</row>
<row>
<entry>tup_returned</entry>
<entry><structfield>tup_returned</></entry>
<entry><type>bigint</></entry>
<entry>The number of rows returned by queries in this database.
<entry>Number of rows returned by queries in this database.
This value can also be returned by directly calling
the <function>pg_stat_get_db_tuples_returned</function> function.</entry>
</row>
<row>
<entry>tup_fetched</entry>
<entry><structfield>tup_fetched</></entry>
<entry><type>bigint</></entry>
<entry>The number of rows fetched by queries in this database.
<entry>Number of rows fetched by queries in this database.
This value can also be returned by directly calling
the <function>pg_stat_get_db_tuples_fetched</function> function.</entry>
</row>
<row>
<entry>tup_inserted</entry>
<entry><structfield>tup_inserted</></entry>
<entry><type>bigint</></entry>
<entry>The number of rows inserted by queries in this database.
<entry>Number of rows inserted by queries in this database.
This value can also be returned by directly calling
the <function>pg_stat_get_db_tuples_inserted</function> function.</entry>
</row>
<row>
<entry>tup_updated</entry>
<entry><structfield>tup_updated</></entry>
<entry><type>bigint</></entry>
<entry>The number of rows updated by queries in this database.
<entry>Number of rows updated by queries in this database.
This value can also be returned by directly calling
the <function>pg_stat_get_db_tuples_updated</function> function.</entry>
</row>
<row>
<entry>tup_deleted</entry>
<entry><structfield>tup_deleted</></entry>
<entry><type>bigint</></entry>
<entry>The number of rows deleted by queries in this database.
<entry>Number of rows deleted by queries in this database.
This value can also be returned by directly calling
the <function>pg_stat_get_db_tuples_deleted</function> function.</entry>
</row>
<row>
<entry>conflicts</entry>
<entry><structfield>conflicts</></entry>
<entry><type>bigint</></entry>
<entry>
The number of queries canceled due to conflict with recovery
(on standby servers) in this database. (See
<xref linkend="pg-stat-database-conflicts-view"> for more details).
<entry>Number of queries canceled due to conflicts with recovery
in this database. (Conflicts occur only on standby servers; see
<xref linkend="pg-stat-database-conflicts-view"> for details.)
This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_all</function> function.
</entry>
</row>
<row>
<entry>temp_files</entry>
<entry><structfield>temp_files</></entry>
<entry><type>bigint</></entry>
<entry>
The number of temporary files written by queries in the database.
<entry>Number of temporary files created by queries in this database.
All temporary files are counted, regardless of why the temporary file
was created (sorting or hash) or file size, and regardless of the
was created (e.g., sorting or hash), and regardless of the
<xref linkend="guc-log-temp-files"> setting.
This value can also be returned by directly calling
the <function>pg_stat_get_db_temp_files</function> function.
</entry>
</row>
<row>
<entry>temp_bytes</entry>
<entry><structfield>temp_bytes</></entry>
<entry><type>bigint</></entry>
<entry>
The amount of data written to temporary files by queries in
the database. All temporary files are counted, regardless of why
the temporary file was created (sorting or hash) or file size, and
<entry>Total amount of data written to temporary files by queries in
this database. All temporary files are counted, regardless of why
the temporary file was created, and
regardless of the <xref linkend="guc-log-temp-files"> setting.
This value can also be returned by directly calling
the <function>pg_stat_get_db_temp_bytes</function> function.
</entry>
</row>
<row>
<entry>deadlocks</entry>
<entry><structfield>deadlocks</></entry>
<entry><type>bigint</></entry>
<entry>Number of deadlocks detected in the database.
<entry>Number of deadlocks detected in this database.
This value can also be returned by directly calling
the <function>pg_stat_get_db_deadlocks</function> function.</entry>
</row>
<row>
<entry>block_read_time</entry>
<entry><structfield>block_read_time</></entry>
<entry><type>bigint</></entry>
<entry>Time spent by backends reading data file blocks, in milliseconds.
<entry>Time spent reading data file blocks by backends in this database,
in milliseconds.
The same value can be returned in microseconds by directly calling
the <function>pg_stat_get_db_block_time_read</function> function.</entry>
</row>
<row>
<entry>block_write_time</entry>
<entry><structfield>block_write_time</></entry>
<entry><type>bigint</></entry>
<entry>Time spent by backends writing data file blocks, in milliseconds.
<entry>Time spent writing data file blocks by backends in this database,
in milliseconds.
The same value can be returned in microseconds by directly calling
the <function>pg_stat_get_db_block_time_write</function> function.</entry>
</row>
<row>
<entry>stats_reset</entry>
<entry><type>timestamptz</></entry>
<entry>The last time the statistics were reset.
<entry><structfield>stats_reset</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>Time at which these statistics were last reset.
This value can also be returned by directly calling
the <function>pg_stat_get_reset_time</function> function.</entry>
</row>
......@@ -1015,194 +932,7 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<para>
The <structname>pg_stat_database</structname> view will contain one row
for each database in the cluster showing database-wide statistics.
</para>
<table id="pg-stat-database-conflicts-view" xreflabel="pg_stat_database_conflicts">
<title>pg_stat_database_conflicts view</title>
<tgroup cols="3">
<thead>
<row>
<entry>Column</entry>
<entry>Type</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>datid</entry>
<entry><type>oid</></entry>
<entry>The OID of the database</entry>
</row>
<row>
<entry>datname</entry>
<entry><type>name</></entry>
<entry>The name of the database</entry>
</row>
<row>
<entry>confl_tablespace</entry>
<entry><type>bigint</></entry>
<entry>The number of queries that have been canceled due to
dropped tablespaces. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_tablespace</function> function.</entry>
</row>
<row>
<entry>confl_lock</entry>
<entry><type>bigint</></entry>
<entry>The number of queries that have been canceled due to
lock timeouts. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_lock</function> function.</entry>
</row>
<row>
<entry>confl_snapshot</entry>
<entry><type>bigint</></entry>
<entry>The number of queries that have been canceled due to
old snapshots. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_snapshot</function> function.</entry>
</row>
<row>
<entry>confl_bufferpin</entry>
<entry><type>bigint</></entry>
<entry>The number of queries that have been canceled due to
pinned buffers. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_bufferpin</function> function.</entry>
</row>
<row>
<entry>confl_deadlock</entry>
<entry><type>bigint</></entry>
<entry>The number of queries that have been canceled due to
deadlocks. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_startup_deadlock</function>
function.</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
The <structname>pg_stat_database_conflicts</structname> view will contain
one row per database showing database-wide statistics about
query cancels due to conflict with recovery on standby servers.
Will only contain information on standby servers, since
conflicts do not occur on master servers.
</para>
<table id="pg-stat-replication-view" xreflabel="pg_stat_replication">
<title>pg_stat_replication view</title>
<tgroup cols="3">
<thead>
<row>
<entry>Column</entry>
<entry>Type</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>pid</entry>
<entry><type>integer</></entry>
<entry>The process id of the WAL sender process</entry>
</row>
<row>
<entry>usesysid</entry>
<entry><type>oid</></entry>
<entry>The OID of the user logged into this WAL sender process</entry>
</row>
<row>
<entry>usename</entry>
<entry><type>name</></entry>
<entry>The name of the user logged into this WAL sender process</entry>
</row>
<row>
<entry>application_name</entry>
<entry><type>text</></entry>
<entry>The name of the application that has initiated the connection
to the WAL sender.</entry>
</row>
<row>
<entry>client_addr</entry>
<entry><type>inet</></entry>
<entry>The remote IP of the client connected to the WAL sender.
If this field is not set, it indicates that the client is
connected via a Unix socket on the server machine.
</entry>
</row>
<row>
<entry>client_hostname</entry>
<entry><type>text</></entry>
<entry>
If available, the hostname of the client as reported by a
reverse lookup of <structfield>client_addr</>. This field will
only be set when <xref linkend="guc-log-hostname"> is enabled.
</entry>
</row>
<row>
<entry>client_port</entry>
<entry><type>integer</></entry>
<entry>
The remote TCP port that the client is using for communication
to the, or <symbol>NULL</> if a unix socket is used.
</entry>
</row>
<row>
<entry>backend_start</entry>
<entry><type>timestamp with time zone</></entry>
<entry>
The time when this process was started, i.e. when the
client connected to the WAL sender.
</entry>
</row>
<row>
<entry>state</entry>
<entry><type>text</></entry>
<entry>Current WAL sender state</entry>
</row>
<row>
<entry>sent_location</entry>
<entry><type>text</></entry>
<entry>Last transaction log position sent on this connection</entry>
</row>
<row>
<entry>write_location</entry>
<entry><type>text</></entry>
<entry>Last transaction log position written to disk by the slave</entry>
</row>
<row>
<entry>flush_location</entry>
<entry><type>text</></entry>
<entry>Last transaction log position flushed to disk by the slave</entry>
</row>
<row>
<entry>replay_location</entry>
<entry><type>text</></entry>
<entry>Last transaction log position replayed into the database on the slave</entry>
</row>
<row>
<entry>sync_priority</entry>
<entry><type>int</></entry>
<entry>
The priority in the order which this slave will be picked as
the synchronous standby.
</entry>
</row>
<row>
<entry>sync_state</entry>
<entry><type>text</></entry>
<entry>
The synchronous state of this slave.
</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
The <structname>pg_stat_replication</structname> view will contain one row
per WAL sender process, showing statistics about the replication to this
slave. Only directly connected standbys are listed; no information about
downstream standby servers is recorded.
for each database in the cluster, showing database-wide statistics.
</para>
<table id="pg-stat-all-tables-view" xreflabel="pg_stat_all_tables">
......@@ -1218,139 +948,144 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<tbody>
<row>
<entry>relid</entry>
<entry><structfield>relid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the table</entry>
<entry>OID of a table</entry>
</row>
<row>
<entry>schemaname</entry>
<entry><structfield>schemaname</></entry>
<entry><type>name</></entry>
<entry>The name of the schema that the table is in</entry>
<entry>Name of the schema that this table is in</entry>
</row>
<row>
<entry>relname</entry>
<entry><structfield>relname</></entry>
<entry><type>name</></entry>
<entry>The name of the table</entry>
<entry>Name of this table</entry>
</row>
<row>
<entry>seq_scan</entry>
<entry><structfield>seq_scan</></entry>
<entry><type>bigint</></entry>
<entry>The number of sequential scans initiated on this table.
<entry>Number of sequential scans initiated on this table.
This value can also be returned by directly calling
the <function>pg_stat_get_numscans</function> function.</entry>
</row>
<row>
<entry>seq_tup_read</entry>
<entry><structfield>seq_tup_read</></entry>
<entry><type>bigint</></entry>
<entry>The number of live rows fetch by sequential scans.
<entry>Number of live rows fetched by sequential scans.
This value can also be returned by directly calling
the <function>pg_stat_get_tuples_returned</function> function.</entry>
</row>
<row>
<entry>idx_scan</entry>
<entry><structfield>idx_scan</></entry>
<entry><type>bigint</></entry>
<entry>The number of index scans initiated on this table</entry>
<entry>Number of index scans initiated on this table</entry>
</row>
<row>
<entry>idx_tup_fetch</entry>
<entry><structfield>idx_tup_fetch</></entry>
<entry><type>bigint</></entry>
<entry>The number of live rows fetch by index scans.</entry>
<entry>Number of live rows fetched by index scans</entry>
</row>
<row>
<entry>n_tup_ins</entry>
<entry><structfield>n_tup_ins</></entry>
<entry><type>bigint</></entry>
<entry>The number of rows inserted.
<entry>Number of rows inserted.
This value can also be returned by directly calling
the <function>pg_stat_get_tuples_inserted</function> function.</entry>
</row>
<row>
<entry>n_tup_upd</entry>
<entry><structfield>n_tup_upd</></entry>
<entry><type>bigint</></entry>
<entry>The number of rows updated.
<entry>Number of rows updated.
This value can also be returned by directly calling
the <function>pg_stat_get_tuples_updated</function> function.</entry>
</row>
<row>
<entry>n_tup_del</entry>
<entry><structfield>n_tup_del</></entry>
<entry><type>bigint</></entry>
<entry>The number of rows deleted.
<entry>Number of rows deleted.
This value can also be returned by directly calling
the <function>pg_stat_get_tuples_deleted</function> function.</entry>
</row>
<row>
<entry>n_tup_hot_upd</entry>
<entry><structfield>n_tup_hot_upd</></entry>
<entry><type>bigint</></entry>
<entry>The number of rows HOT (i.e., no separate index update) updated.
<entry>Number of rows HOT updated (i.e., with no separate index
update required).
This value can also be returned by directly calling
the <function>pg_stat_get_tuples_hot_updated</function> function.</entry>
</row>
<row>
<entry>n_live_tup</entry>
<entry><structfield>n_live_tup</></entry>
<entry><type>bigint</></entry>
<entry>The number of live rows.
<entry>Estimated number of live rows.
This value can also be returned by directly calling
the <function>pg_stat_get_live_tuples</function> function.</entry>
</row>
<row>
<entry>n_dead_tup</entry>
<entry><structfield>n_dead_tup</></entry>
<entry><type>bigint</></entry>
<entry>The number of dead rows.
<entry>Estimated number of dead rows.
This value can also be returned by directly calling
the <function>pg_stat_get_dead_tuples</function> function.</entry>
</row>
<row>
<entry>last_vacuum</entry>
<entry><structfield>last_vacuum</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>The last time the table was manually non-<option>FULL</> vacuumed.
<entry>Last time at which this table was manually vacuumed
(not counting <command>VACUUM FULL</>).
This value can also be returned by directly calling
the <function>pg_stat_get_last_vacuum_time</function> function.</entry>
</row>
<row>
<entry>last_autovacuum</entry>
<entry><structfield>last_autovacuum</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>The last time the table was vacuumed by the autovacuum daemon.
<entry>Last time at which this table was vacuumed by the autovacuum
daemon.
This value can also be returned by directly calling
the <function>pg_stat_get_last_autovacuum_time</function> function.</entry>
</row>
<row>
<entry>last_analyze</entry>
<entry><structfield>last_analyze</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>The last time the table was manually analyzed.
<entry>Last time at which this table was manually analyzed.
This value can also be returned by directly calling
the <function>pg_stat_get_last_analyze_time</function> function.</entry>
</row>
<row>
<entry>last_autoanalyze</entry>
<entry><structfield>last_autoanalyze</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>The last time the table was analyzed by the autovacuum daemon.
<entry>Last time at which this table was analyzed by the autovacuum
daemon.
This value can also be returned by directly calling
the <function>pg_stat_get_last_autoanalyze_time</function> function.</entry>
</row>
<row>
<entry>vacuum_count</entry>
<entry><structfield>vacuum_count</></entry>
<entry><type>bigint</></entry>
<entry>The number of times this table has been manually non-<option>FULL</> vacuumed.
This value can also be returned by directly calling
the <function>pg_stat_get_vacuum_count</function> function.</entry>
<entry>Number of times this table has been manually vacuumed
(not counting <command>VACUUM FULL</>)</entry>
</row>
<row>
<entry>autovacuum_count</entry>
<entry><structfield>autovacuum_count</></entry>
<entry><type>bigint</></entry>
<entry>The number of times this table has been vacuumed by the autovacuum daemon.
<entry>Number of times this table has been vacuumed by the autovacuum
daemon.
This value can also be returned by directly calling
the <function>pg_stat_get_autovacuum_count</function> function.</entry>
</row>
<row>
<entry>analyze_count</entry>
<entry><structfield>analyze_count</></entry>
<entry><type>bigint</></entry>
<entry>The number of times this table has been manually analyzed.
<entry>Number of times this table has been manually analyzed.
This value can also be returned by directly calling
the <function>pg_stat_get_analyze_count</function> function.</entry>
</row>
<row>
<entry>autoanalyze_count</entry>
<entry><structfield>autoanalyze_count</></entry>
<entry><type>bigint</></entry>
<entry>The number of times this table has been analyzed by the autovacuum daemon.
<entry>Number of times this table has been analyzed by the autovacuum
daemon.
This value can also be returned by directly calling
the <function>pg_stat_get_autoanalyze_count</function> function.</entry>
</row>
......@@ -1361,10 +1096,11 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<para>
The <structname>pg_stat_all_tables</structname> view will contain
one row for each table in the current database (including TOAST
tables) with information about accesses to this specific table. The
tables), showing statistics about accesses to that specific table. The
<structname>pg_stat_user_tables</structname> and
<structname>pg_stat_sys_tables</structname> contain the same information,
but filtered to only have rows for user and system tables.
<structname>pg_stat_sys_tables</structname> views
contain the same information,
but filtered to only show user and system tables respectively.
</para>
<table id="pg-stat-all-indexes-view" xreflabel="pg_stat_all_indexes">
......@@ -1380,48 +1116,49 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<tbody>
<row>
<entry>relid</entry>
<entry><structfield>relid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the table for this index</entry>
<entry>OID of the table for this index</entry>
</row>
<row>
<entry>indexrelid</entry>
<entry><structfield>indexrelid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the index</entry>
<entry>OID of this index</entry>
</row>
<row>
<entry>schemaname</entry>
<entry><structfield>schemaname</></entry>
<entry><type>name</></entry>
<entry>The name of the schema the index is in</entry>
<entry>Name of the schema this index is in</entry>
</row>
<row>
<entry>relname</entry>
<entry><structfield>relname</></entry>
<entry><type>name</></entry>
<entry>The name of the table for this index</entry>
<entry>Name of the table for this index</entry>
</row>
<row>
<entry>indexrelname</entry>
<entry><structfield>indexrelname</></entry>
<entry><type>name</></entry>
<entry>The name of the index</entry>
<entry>Name of this index</entry>
</row>
<row>
<entry>idx_scan</entry>
<entry><structfield>idx_scan</></entry>
<entry><type>bigint</></entry>
<entry>Number of index scans initiated on this index.
This value can also be returned by directly calling
the <function>pg_stat_get_numscans</function> function.</entry>
</row>
<row>
<entry>idx_tup_read</entry>
<entry><structfield>idx_tup_read</></entry>
<entry><type>bigint</></entry>
<entry>Number of index entries returned by scans on this index.
This value can also be returned by directly calling
the <function>pg_stat_get_tuples_returned</function> function.</entry>
</row>
<row>
<entry>idx_tup_fetch</entry>
<entry><structfield>idx_tup_fetch</></entry>
<entry><type>bigint</></entry>
<entry>Number of live table rows fetched by simple index scans using this index.
<entry>Number of live table rows fetched by simple index scans using this
index.
This value can also be returned by directly calling
the <function>pg_stat_get_tuples_fetched</function> function.</entry>
</row>
......@@ -1431,13 +1168,40 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<para>
The <structname>pg_stat_all_indexes</structname> view will contain
one row for each index in the current database
with information about accesses to this specific index. The
one row for each index in the current database,
showing statistics about accesses to that specific index. The
<structname>pg_stat_user_indexes</structname> and
<structname>pg_stat_sys_indexes</structname> contain the same information,
but filtered to only have rows for user and system indexes.
<structname>pg_stat_sys_indexes</structname> views
contain the same information,
but filtered to only show user and system indexes respectively.
</para>
<para>
Indexes can be used via either simple index scans or <quote>bitmap</>
index scans. In a bitmap scan
the output of several indexes can be combined via AND or OR rules,
so it is difficult to associate individual heap row fetches
with specific indexes when a bitmap scan is used. Therefore, a bitmap
scan increments the
<structname>pg_stat_all_indexes</>.<structfield>idx_tup_read</>
count(s) for the index(es) it uses, and it increments the
<structname>pg_stat_all_tables</>.<structfield>idx_tup_fetch</>
count for the table, but it does not affect
<structname>pg_stat_all_indexes</>.<structfield>idx_tup_fetch</>.
</para>
<note>
<para>
The <structfield>idx_tup_read</> and <structfield>idx_tup_fetch</> counts
can be different even without any use of bitmap scans,
because <structfield>idx_tup_read</> counts
index entries retrieved from the index while <structfield>idx_tup_fetch</>
counts live rows fetched from the table. The latter will be less if any
dead or not-yet-committed rows are fetched using the index, or if any
heap fetches are avoided by means of an index-only scan.
</para>
</note>
<table id="pg-statio-all-tables-view" xreflabel="pg_statio_all_tables">
<title>pg_statio_all_tables view</title>
<tgroup cols="3">
......@@ -1451,23 +1215,23 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<tbody>
<row>
<entry>relid</entry>
<entry><structfield>relid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the table</entry>
<entry>OID of a table</entry>
</row>
<row>
<entry>schemaname</entry>
<entry><structfield>schemaname</></entry>
<entry><type>name</></entry>
<entry>The name of the schema that the table is in</entry>
<entry>Name of the schema that this table is in</entry>
</row>
<row>
<entry>relname</entry>
<entry><structfield>relname</></entry>
<entry><type>name</></entry>
<entry>The name of the table</entry>
<entry>Name of this table</entry>
</row>
<row>
<entry>heap_blks_read</entry>
<entry><type>name</></entry>
<entry><structfield>heap_blks_read</></entry>
<entry><type>bigint</></entry>
<entry>Number of disk blocks read from this table.
This value can also be returned by directly calling
the <function>pg_stat_get_blocks_fetched</function> and
......@@ -1475,40 +1239,40 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
subtracting the results.</entry>
</row>
<row>
<entry>heap_blks_hit</entry>
<entry><type>name</></entry>
<entry><structfield>heap_blks_hit</></entry>
<entry><type>bigint</></entry>
<entry>Number of buffer hits in this table.
This value can also be returned by directly calling
the <function>pg_stat_get_blocks_hit</function> function.</entry>
</row>
<row>
<entry>idx_blks_read</entry>
<entry><type>name</></entry>
<entry><structfield>idx_blks_read</></entry>
<entry><type>bigint</></entry>
<entry>Number of disk blocks read from all indexes on this table</entry>
</row>
<row>
<entry>idx_blks_hit</entry>
<entry><type>name</></entry>
<entry>Number of buffer hits in all indexes of this table.</entry>
<entry><structfield>idx_blks_hit</></entry>
<entry><type>bigint</></entry>
<entry>Number of buffer hits in all indexes of this table</entry>
</row>
<row>
<entry>toast_blks_read</entry>
<entry><type>name</></entry>
<entry><structfield>toast_blks_read</></entry>
<entry><type>bigint</></entry>
<entry>Number of disk blocks read from this table's TOAST table (if any)</entry>
</row>
<row>
<entry>toast_blks_hit</entry>
<entry><type>name</></entry>
<entry><structfield>toast_blks_hit</></entry>
<entry><type>bigint</></entry>
<entry>Number of buffer hits in this table's TOAST table (if any)</entry>
</row>
<row>
<entry>tidx_blks_read</entry>
<entry><type>name</></entry>
<entry><structfield>tidx_blks_read</></entry>
<entry><type>bigint</></entry>
<entry>Number of disk blocks read from this table's TOAST table index (if any)</entry>
</row>
<row>
<entry>tidx_blks_hit</entry>
<entry><type>name</></entry>
<entry><structfield>tidx_blks_hit</></entry>
<entry><type>bigint</></entry>
<entry>Number of buffer hits in this table's TOAST table index (if any)</entry>
</row>
</tbody>
......@@ -1518,10 +1282,11 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<para>
The <structname>pg_statio_all_tables</structname> view will contain
one row for each table in the current database (including TOAST
tables) with information about I/O on this specific table. The
tables), showing statistics about I/O on that specific table. The
<structname>pg_statio_user_tables</structname> and
<structname>pg_statio_sys_tables</structname> contain the same information,
but filtered to only have rows for user and system tables.
<structname>pg_statio_sys_tables</structname> views
contain the same information,
but filtered to only show user and system tables respectively.
</para>
<table id="pg-statio-all-indexes-view" xreflabel="pg_statio_all_indexes">
......@@ -1537,43 +1302,43 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<tbody>
<row>
<entry>relid</entry>
<entry><structfield>relid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the table for this index</entry>
<entry>OID of the table for this index</entry>
</row>
<row>
<entry>indexrelid</entry>
<entry><structfield>indexrelid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the index</entry>
<entry>OID of this index</entry>
</row>
<row>
<entry>schemaname</entry>
<entry><structfield>schemaname</></entry>
<entry><type>name</></entry>
<entry>The name of the schema the index is in</entry>
<entry>Name of the schema this index is in</entry>
</row>
<row>
<entry>relname</entry>
<entry><structfield>relname</></entry>
<entry><type>name</></entry>
<entry>The name of the table for this index</entry>
<entry>Name of the table for this index</entry>
</row>
<row>
<entry>indexrelname</entry>
<entry><structfield>indexrelname</></entry>
<entry><type>name</></entry>
<entry>The name of the index</entry>
<entry>Name of this index</entry>
</row>
<row>
<entry>idx_blks_read</entry>
<entry><type>name</></entry>
<entry>Number of disk blocks read from the index.
<entry><structfield>idx_blks_read</></entry>
<entry><type>bigint</></entry>
<entry>Number of disk blocks read from this index.
This value can also be returned by directly calling
the <function>pg_stat_get_blocks_fetched</function> and
<function>pg_stat_get_blocks_hit</function> functions and
subtracting the results.</entry>
</row>
<row>
<entry>idx_blks_hit</entry>
<entry><type>name</></entry>
<entry>Number of buffer hits in the index.
<entry><structfield>idx_blks_hit</></entry>
<entry><type>bigint</></entry>
<entry>Number of buffer hits in this index.
This value can also be returned by directly calling
the <function>pg_stat_get_blocks_hit</function> function.</entry>
</row>
......@@ -1583,11 +1348,12 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<para>
The <structname>pg_statio_all_indexes</structname> view will contain
one row for each index in the current database
with information about I/O on this specific index. The
one row for each index in the current database,
showing statistics about I/O on that specific index. The
<structname>pg_statio_user_indexes</structname> and
<structname>pg_statio_sys_indexes</structname> contain the same information,
but filtered to only have rows for user and system indexes.
<structname>pg_statio_sys_indexes</structname> views
contain the same information,
but filtered to only show user and system indexes respectively.
</para>
<table id="pg-statio-all-sequences-view" xreflabel="pg_statio_all_sequences">
......@@ -1603,38 +1369,38 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<tbody>
<row>
<entry>relid</entry>
<entry><structfield>relid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the sequence</entry>
<entry>OID of a sequence</entry>
</row>
<row>
<entry>schemaname</entry>
<entry><structfield>schemaname</></entry>
<entry><type>name</></entry>
<entry>The name of the schema the sequence is in</entry>
<entry>Name of the schema this sequence is in</entry>
</row>
<row>
<entry>relname</entry>
<entry><structfield>relname</></entry>
<entry><type>name</></entry>
<entry>The name of the sequence</entry>
<entry>Name of this sequence</entry>
</row>
<row>
<entry>blks_read</entry>
<entry><type>name</></entry>
<entry>Number of disk blocks read from the sequence</entry>
<entry><structfield>blks_read</></entry>
<entry><type>bigint</></entry>
<entry>Number of disk blocks read from this sequence</entry>
</row>
<row>
<entry>blks_hit</entry>
<entry><type>name</></entry>
<entry>Number of buffer hits in the sequence</entry>
<entry><structfield>blks_hit</></entry>
<entry><type>bigint</></entry>
<entry>Number of buffer hits in this sequence</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
The <structname>pg_statio_all_indexes</structname> view will contain
one row for each sequence in the current database
with information about I/O on this specific sequence.
The <structname>pg_statio_all_sequences</structname> view will contain
one row for each sequence in the current database,
showing statistics about I/O on that specific sequence.
</para>
<table id="pg-stat-user-functions-view" xreflabel="pg_stat_user_functions">
......@@ -1650,39 +1416,39 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<tbody>
<row>
<entry>funcid</entry>
<entry><structfield>funcid</></entry>
<entry><type>oid</></entry>
<entry>The OID of the function</entry>
<entry>OID of a function</entry>
</row>
<row>
<entry>schemaname</entry>
<entry><structfield>schemaname</></entry>
<entry><type>name</></entry>
<entry>The name of the schema the function is in</entry>
<entry>Name of the schema this function is in</entry>
</row>
<row>
<entry>funcname</entry>
<entry><structfield>funcname</></entry>
<entry><type>name</></entry>
<entry>The name of the function</entry>
<entry>Name of this function</entry>
</row>
<row>
<entry>calls</entry>
<entry><structfield>calls</></entry>
<entry><type>bigint</></entry>
<entry>Number of times the function has been called.
<entry>Number of times this function has been called.
This value can also be returned by directly calling
the <function>pg_stat_get_function_calls</function> function.</entry>
</row>
<row>
<entry>total_time</entry>
<entry><structfield>total_time</></entry>
<entry><type>bigint</></entry>
<entry>Total time spent in this functions and all other functions
<entry>Total time spent in this function and all other functions
called by it, in milliseconds.
The same value can be returned in microseconds by directly calling
the <function>pg_stat_get_function_time</function> function.</entry>
</row>
<row>
<entry>self_time</entry>
<entry><structfield>self_time</></entry>
<entry><type>bigint</></entry>
<entry>Total time spent in this functions itself but not including
<entry>Total time spent in this function itself, not including
other functions called by it, in milliseconds.
The same value can be returned in microseconds by directly calling
the <function>pg_stat_get_function_self_time</function> function.</entry>
......@@ -1693,13 +1459,218 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<para>
The <structname>pg_stat_user_functions</structname> view will contain
one row for each tracked function (as specified by the
<xref linkend="guc-track-functions"> parameter).
one row for each tracked function, showing statistics about executions of
that function. The <xref linkend="guc-track-functions"> parameter
controls exactly which functions are tracked.
</para>
<table id="pg-stat-replication-view" xreflabel="pg_stat_replication">
<title>pg_stat_replication view</title>
<tgroup cols="3">
<thead>
<row>
<entry>Column</entry>
<entry>Type</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry><structfield>pid</></entry>
<entry><type>integer</></entry>
<entry>Process ID of a WAL sender process</entry>
</row>
<row>
<entry><structfield>usesysid</></entry>
<entry><type>oid</></entry>
<entry>OID of the user logged into this WAL sender process</entry>
</row>
<row>
<entry><structfield>usename</></entry>
<entry><type>name</></entry>
<entry>Name of the user logged into this WAL sender process</entry>
</row>
<row>
<entry><structfield>application_name</></entry>
<entry><type>text</></entry>
<entry>Name of the application that is connected
to this WAL sender</entry>
</row>
<row>
<entry><structfield>client_addr</></entry>
<entry><type>inet</></entry>
<entry>IP address of the client connected to this WAL sender.
If this field is not set, it indicates that the client is
connected via a Unix socket on the server machine.
</entry>
</row>
<row>
<entry><structfield>client_hostname</></entry>
<entry><type>text</></entry>
<entry>Host name of the connected client, as reported by a
reverse DNS lookup of <structfield>client_addr</>. This field will
only be set for IP connections, and only when <xref
linkend="guc-log-hostname"> is enabled.
</entry>
</row>
<row>
<entry><structfield>client_port</></entry>
<entry><type>integer</></entry>
<entry>TCP port number that the client is using for communication
with this WAL sender, or <symbol>NULL</> if a Unix socket is used
</entry>
</row>
<row>
<entry><structfield>backend_start</></entry>
<entry><type>timestamp with time zone</></entry>
<entry>Time when this process was started, i.e., when the
client connected to this WAL sender
</entry>
</row>
<row>
<entry><structfield>state</></entry>
<entry><type>text</></entry>
<entry>Current WAL sender state</entry>
</row>
<row>
<entry><structfield>sent_location</></entry>
<entry><type>text</></entry>
<entry>Last transaction log position sent on this connection</entry>
</row>
<row>
<entry><structfield>write_location</></entry>
<entry><type>text</></entry>
<entry>Last transaction log position written to disk by this standby
server</entry>
</row>
<row>
<entry><structfield>flush_location</></entry>
<entry><type>text</></entry>
<entry>Last transaction log position flushed to disk by this standby
server</entry>
</row>
<row>
<entry><structfield>replay_location</></entry>
<entry><type>text</></entry>
<entry>Last transaction log position replayed into the database on this
standby server</entry>
</row>
<row>
<entry><structfield>sync_priority</></entry>
<entry><type>integer</></entry>
<entry>Priority of this standby server for being chosen as the
synchronous standby</entry>
</row>
<row>
<entry><structfield>sync_state</></entry>
<entry><type>text</></entry>
<entry>Synchronous state of this standby server</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
The <structname>pg_stat_replication</structname> view will contain one row
per WAL sender process, showing statistics about replication to that
sender's connected standby server. Only directly connected standbys are
listed; no information is available about downstream standby servers.
</para>
<table id="pg-stat-database-conflicts-view" xreflabel="pg_stat_database_conflicts">
<title>pg_stat_database_conflicts view</title>
<tgroup cols="3">
<thead>
<row>
<entry>Column</entry>
<entry>Type</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry><structfield>datid</></entry>
<entry><type>oid</></entry>
<entry>OID of a database</entry>
</row>
<row>
<entry><structfield>datname</></entry>
<entry><type>name</></entry>
<entry>Name of this database</entry>
</row>
<row>
<entry><structfield>confl_tablespace</></entry>
<entry><type>bigint</></entry>
<entry>Number of queries in this database that have been canceled due to
dropped tablespaces. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_tablespace</function> function.</entry>
</row>
<row>
<entry><structfield>confl_lock</></entry>
<entry><type>bigint</></entry>
<entry>Number of queries in this database that have been canceled due to
lock timeouts. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_lock</function> function.</entry>
</row>
<row>
<entry><structfield>confl_snapshot</></entry>
<entry><type>bigint</></entry>
<entry>Number of queries in this database that have been canceled due to
old snapshots. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_snapshot</function> function.</entry>
</row>
<row>
<entry><structfield>confl_bufferpin</></entry>
<entry><type>bigint</></entry>
<entry>Number of queries in this database that have been canceled due to
pinned buffers. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_bufferpin</function> function.</entry>
</row>
<row>
<entry><structfield>confl_deadlock</></entry>
<entry><type>bigint</></entry>
<entry>Number of queries in this database that have been canceled due to
deadlocks. This value can also be returned by directly calling
the <function>pg_stat_get_db_conflict_startup_deadlock</function>
function.</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
The <structname>pg_stat_database_conflicts</structname> view will contain
one row per database, showing database-wide statistics about
query cancels occurring due to conflicts with recovery on standby servers.
This view will only contain information on standby servers, since
conflicts do not occur on master servers.
</para>
<sect3 id="monitoring-stats-functions">
<title>Other Statistics Functions</title>
</sect2>
<sect2 id="monitoring-stats-functions">
<title>Statistics Functions</title>
<para>
Other ways of looking at the statistics can be set up by writing
queries that use the same underlying statistics access functions as
the standard views do. The per-database access
functions take a database OID as an argument to identify which
database to report on. The per-table and per-index functions take
a table or index OID. The functions for function-call statistics
take a function OID. (Note that only tables, indexes, and functions
in the current database can be seen with these functions.) The
per-server-process access functions take a server process
number, which ranges from one to the number of currently active
server processes.
</para>
<para>
Additional functions related to statistics collection are listed in <xref
linkend="monitoring-stats-funcs-table">.
</para>
<table id="monitoring-stats-funcs-table">
<title>Other Statistics Functions</title>
......@@ -1720,7 +1691,7 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<entry><literal><function>pg_backend_pid()</function></literal></entry>
<entry><type>integer</type></entry>
<entry>
Process ID of the server process attached to the current session
Process ID of the server process handling the current session
</entry>
</row>
......@@ -1744,12 +1715,11 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
</entry>
</row>
<row>
<entry><literal><function>pg_stat_get_wal_senders()</function></literal></entry>
<entry><type>setof record</type></entry>
<entry>
One record for each active wal sender. The fields returned are a subset
One record for each active WAL sender. The fields returned are a subset
of those in the <structname>pg_stat_replication</structname> view.
</entry>
</row>
......@@ -1775,10 +1745,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
<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</>.
Reset some cluster-wide statistics counters to zero, depending on the
argument (requires superuser privileges).
Calling <literal>pg_stat_reset_shared('bgwriter')</> will zero all the
counters shown in the <structname>pg_stat_bgwriter</> view.
</entry>
</row>
......@@ -1803,7 +1773,21 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
</tgroup>
</table>
</sect3>
<para>
All the underlying functions of the <structname>pg_stat_activity</> view
require a backend ID number.
The function <function>pg_stat_get_backend_idset</function> provides a
convenient way to generate one row for each active server process for
invoking these functions. For example, to show the <acronym>PID</>s and
current queries of all server processes:
<programlisting>
SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
pg_stat_get_backend_activity(s.backendid) AS query
FROM (SELECT pg_stat_get_backend_idset() AS backendid) AS s;
</programlisting>
</para>
</sect2>
</sect1>
......
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