Idle transactions in PostgreSQL 9.2.4

Hi all,

I have some idle transactions in PostgreSQL 9.2.4 server which never end.
My application was working fine on version 9.1 (BSD) but the problem
appeared immediately as we ported it to 9.2.4 on Linux. The idle operations
would frequently appear as COMMITs but sometimes I observed INSERTS as well.
Please note that each commit below refers to *very light* inserts of single
rows which are supposed to last milliseconds. However some of the just
never end even if they are not waiting on other operations. See below:

SELECT datname,usename,pid,client_addr,waiting,query_start,query FROM
pg_stat_activity;

datname | usename | pid | client_addr | waiting | query_start
| query

----------+-----------+-------+-------------+---------+-------------------------------
AppQoSDB | appqosusr | 17015 | 127.0.0.1 | f | 2013-10-15
10:21:38.501435+01 | select AppQoSConfig.get_ip_currentnode()
AppQoSDB | appqosusr | 17016 | 127.0.0.1 | f | 2013-10-15
10:21:38.502346+01 | COMMIT
AppQoSDB | appqosusr | 17017 | 127.0.0.1 | f | 2013-10-15
10:21:38.584794+01 | select AppQoSConfig.get_ip_currentnode()
AppQoSDB | appqosusr | 17018 | 127.0.0.1 | f | 2013-10-15
10:21:38.586073+01 | COMMIT
AppQoSDB | appqosusr | 17019 | 127.0.0.1 | f | 2013-10-15
09:20:32.724517+01 | select AppQoSConfig.get_ip_currentnode()
AppQoSDB | appqosusr | 17021 | 127.0.0.1 | f | 2013-10-15
10:21:38.622651+01 | select AppQoSConfig.get_ip_currentnode()
AppQoSDB | appqosusr | 17020 | 127.0.0.1 | f | 2013-10-15
09:20:32.724433+01 | select AppQoSConfig.get_ip_currentnode()
AppQoSDB | appqosusr | 17022 | 127.0.0.1 | f | 2013-10-15
10:21:37.368831+01 | select AppQoSConfig.get_ip_currentnode()
AppQoSDB | appqosusr | 17024 | 127.0.0.1 | f | 2013-10-15
09:20:32.828307+01 | COMMIT
AppQoSDB | appqosusr | 17026 | 127.0.0.1 | f | 2013-10-15
10:21:38.624378+01 | COMMIT
AppQoSDB | appqosusr | 17023 | 127.0.0.1 | f | 2013-10-15
09:20:32.828302+01 | COMMIT
AppQoSDB | appqosusr | 17025 | 127.0.0.1 | f | 2013-10-15
10:21:37.369869+01 | COMMIT
AppQoSDB | appqosusr | 17027 | 127.0.0.1 | f | 2013-10-15
10:21:38.633244+01 | SELECT
datname,usename,pid,client_addr,waiting,query_start,query FROM
pg_stat_activity;

This is the current configuration:

name |
current_setting
------------------------------+------------------------------------------------------------------------------------------------------------
version | PostgreSQL 9.2.4 on
x86_64-unknown-linux-gnu, compiled by gcc (Ubuntu/Linaro 4.7.2-2ubuntu1)
4.7.2, 64-bit
autovacuum | on
autovacuum_analyze_threshold | 500000
autovacuum_max_workers | 1
autovacuum_naptime | 1h
autovacuum_vacuum_threshold | 500000
checkpoint_completion_target | 0.7
checkpoint_segments | 128
checkpoint_warning | 30s
client_encoding | UTF8
effective_cache_size | 16GB
lc_collate | en_GB.UTF-8
lc_ctype | en_GB.UTF-8
listen_addresses | *
log_destination | syslog, stderr
log_min_duration_statement | 2min
log_rotation_age | 10d
log_rotation_size | 100MB
logging_collector | on
max_connections | 200
max_stack_depth | 2MB
server_encoding | UTF8
shared_buffers | 6GB
synchronous_commit | off
TimeZone | GB
wal_buffers | 128kB
work_mem | 18MB

Thank you,
Svetlin Manavski