Added kill_idle stored procedures.

Author: Josh Berkus

README.md

@@ -2,3 +2,16 @@ pgx_scripts
 ===========
 
 A collection of useful little scripts for database analysis and administration, created by our team at PostgreSQL Experts.
+
+administration
+==============
+
+kill_idle_91.sql
+----------------
+
+A stored procedure which kills idle transactions on PostgreSQL versions 8.3 to 9.1.  Intended to be called by a cron job.  Takes idle time, polling time, and exempted user list parameters.  Outputs pipe-delimited text with the data about the sessions killed.
+
+kill_idle_93.sql
+----------------
+
+A stored procedure which kills idle transactions on PostgreSQL versions 9.2 and later.  Intended to be called by a cron job.  Takes idle time and exempted user list parameters.  Outputs JSON with the data about the sessions killed.

administration/kill_idle_91.sql

@@ -0,0 +1,47 @@
+create or replace function kill_idle_transactions_91 (
+    timelimit INTERVAL DEFAULT '10 minutes',
+    safe_users TEXT[] DEFAULT '{}',
+    wait_time INT DEFAULT 10)
+returns SETOF text
+language plpgsql
+as
+$f$
+declare idles INT[];
+    cancelled RECORD;
+    output TEXT;
+    
+begin
+
+    SELECT array_agg(procpid)
+    INTO idles
+    FROM pg_stat_activity
+    WHERE current_query = '<IDLE> in transaction'
+    AND ( now() - xact_start ) > timelimit
+        AND ( usename != ANY(safe_users)
+            OR safe_users = '{}' );
+
+    IF idles IS NULL THEN
+        RETURN;
+    END IF;
+    
+    PERFORM pg_sleep(wait_time);
+
+    FOR cancelled IN
+            SELECT pg_stat_activity.*, pg_terminate_backend(procpid)
+            FROM pg_stat_activity
+            WHERE procpid = ANY ( idles )
+            AND current_query = '<IDLE> in transaction' LOOP
+
+        output := array_to_string(ARRAY[ now()::TEXT,
+                cancelled.datname::TEXT, cancelled.procpid::TEXT, cancelled.usename::TEXT,
+                cancelled.application_name, cancelled.client_addr::TEXT,
+                cancelled.backend_start::TEXT, cancelled.xact_start::TEXT,
+                cancelled.waiting::TEXT], '|');
+
+        RETURN NEXT output;
+
+    END LOOP;
+
+    RETURN;
+
+end; $f$;

administration/kill_idle_93.sql

@@ -0,0 +1,38 @@
+create or replace function kill_idle_transactions (
+    timelimit INTERVAL DEFAULT '10 minutes',
+    safe_users TEXT[] DEFAULT '{}')
+returns SETOF json
+language plpgsql
+as
+$f$
+declare
+    cancelled JSON;
+    
+begin
+
+    FOR cancelled IN
+        WITH terminated AS (
+            SELECT pg_stat_activity.*, pg_terminate_backend(pid)
+            FROM pg_stat_activity
+            WHERE state = 'idle in transaction'
+              AND (now() - state_change) > timelimit
+              AND ( usename != ANY(safe_users)
+                    OR safe_users = '{}' )),
+        termformat AS (
+            SELECT now() as killtime,
+                datname, pid, usename, application_name,
+                client_addr, backend_start, xact_start,
+                state_change, waiting, "query"
+            FROM terminated )
+        SELECT row_to_json(termformat.*)
+        FROM termformat
+        LOOP
+        
+        RETURN NEXT cancelled;
+
+    END LOOP;
+
+    RETURN;
+
+end; $f$;
+