Turn PGBE_ACTIVITY_SIZE into a GUC variable, track_activity_query_size.

As the buffer could now be a lot larger than before, and copying it could
thus be a lot more expensive than before, use strcpy instead of memcpy to
copy the query string, as was already suggested in comments. Also, only copy
the PgBackendStatus struct and string if the slot is in use.

Patch by Thomas Lee, with some changes by me.

1 files changed, 17 insertions, 1 deletions

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index f25ed24986c..97cf9452617 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.180 2008/06/14 21:59:59 alvherre Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.181 2008/06/30 10:58:47 heikki Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -3331,6 +3331,22 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-track-activity-query-size" xreflabel="track_activity_query_size">
+      <term><varname>track_activity_query_size</varname> (<type>integer</type>)</term>
+      <indexterm>
+       <primary><varname>track_activity_query_size</> configuration parameter</primary>
+      </indexterm>
+      <listitem>
+       <para>
+       Specifies the number of bytes reserved to track the currently
+       executing command for each active session, for the
+       <structname>pg_stat_activity</>.<structfield>current_query</> field.
+       The default value is 1024. This parameter can only be set at server
+       start.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry id="guc-track-counts" xreflabel="track_counts">
       <term><varname>track_counts</varname> (<type>boolean</type>)</term>
       <indexterm>