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IDProjectCategoryView StatusDate SubmittedLast Update
0000655Pgpool-IIBugpublic2020-10-21 12:522020-10-29 21:57
Reporterkansvignesh Assigned Tot-ishii  
PrioritynormalSeveritymajorReproducibilityrandom
Status feedbackResolutionopen 
PlatformLinuxOSUbuntuOS Version18
Product Version4.0.1 
Summary0000655: pgpool drops connections
DescriptionThe pgpool has 2 db back-ends with master/slave in streaming replication. The app uses a specific number of pgpool connections, which it uses for transactions. The app always keep the connections active - however pgpool stops dropping the connection. Even though the app tries to re-create new connection, pgpool seems to be dropping them as well. The only workaround when this occurs is to restart pgpool itself.

During the issue, we see many entries of "ERROR: unable to read data from frontend" and "EOF read on socket" in the logs. The errors stop if pgpool is restarted.

Some examples with pgpool child process details

#pid 14635
Oct 21 08:54:36 host1 pgpool[14386]: 2020-10-21 08:54:36: pid 14635: ERROR: unable to read data from frontend
Oct 21 08:54:36 host1 pgpool[14386]: 2020-10-21 08:54:36: pid 14635: DETAIL: EOF read on socket
Oct 21 08:59:36 host1 pgpool[14386]: 2020-10-21 08:59:36: pid 14386: LOG: child process with pid: 14635 exits with status 256

=======

#pid 14495
Oct 21 08:57:29 host1 pgpool[14386]: 2020-10-21 08:57:29: pid 14495: ERROR: unable to read data from frontend
Oct 21 08:57:29 host1 pgpool[14386]: 2020-10-21 08:57:29: pid 14495: DETAIL: EOF read on socket
Oct 21 09:02:29 host1 pgpool[14386]: 2020-10-21 09:02:29: pid 14386: LOG: child process with pid: 14495 exits with status 256

=======

#pid 7190
Oct 21 09:09:11 host1 pgpool[14386]: 2020-10-21 09:09:11: pid 7190: LOG: new connection received
Oct 21 09:09:11 host1 pgpool[14386]: 2020-10-21 09:09:11: pid 7190: DETAIL: connecting host=localhost port=55982
Oct 21 09:09:11 host1 pgpool[14386]: 2020-10-21 09:09:11: pid 7190: LOG: md5 authentication successful with frontend
Oct 21 09:09:51 host1 pgpool[14386]: 2020-10-21 09:09:51: pid 7190: ERROR: unable to read data from frontend
Oct 21 09:09:51 host1 pgpool[14386]: 2020-10-21 09:09:51: pid 7190: DETAIL: EOF read on socket

======================

pgool key config:
num_init_children = 192
max_pool = 2

# - Life time -
child_life_time = 300
child_max_connections = 0
connection_life_time = 0
client_idle_limit = 0

#------------------------------------------------------------------------------
# CONNECTION POOLING
#------------------------------------------------------------------------------
connection_cache = on
reset_query_list = 'ABORT; DISCARD ALL'

#------------------------------------------------------------------------------
# LOAD BALANCING MODE
#------------------------------------------------------------------------------
load_balance_mode = on
ignore_leading_white_space = on
white_function_list = ''
black_function_list = 'currval,lastval,nextval,setval'
allow_sql_comments = on

#------------------------------------------------------------------------------
# MASTER/SLAVE MODE
#------------------------------------------------------------------------------
master_slave_mode = on
master_slave_sub_mode = 'stream'

Steps To ReproduceThis occurs randomly - we have seen this issue 2-3 months once in the past. This again occurred recently but not sure what triggers this.
Additional InformationSorry if the information posted here is not enough - please let me know what is needed so that I can add it here. If upgrading pgpool will help, please let me know the version to upgrade to, thanks.

Thanks in advance. Cheers.
Tagsunable to read data from frontend

Activities

t-ishii

2020-10-22 09:39

developer   ~0003589

Pgpool-II 4.0.1 is pretty old (released 2 years ago). Please upgrade to the latest 4.0.x version. If you still see the problem, please let me know.

Issue History

Date Modified Username Field Change
2020-10-21 12:52 kansvignesh New Issue
2020-10-21 12:52 kansvignesh Tag Attached: unable to read data from frontend
2020-10-22 09:39 t-ishii Assigned To => t-ishii
2020-10-22 09:39 t-ishii Status new => assigned
2020-10-22 09:39 t-ishii Note Added: 0003589
2020-10-29 21:57 t-ishii Status assigned => feedback