[pgpool-general: 948] server sent data ("D" message) without prior row description ("T" message)

Wed Sep 5 03:16:11 JST 2012

Hi,

I'm having issues with a fresh setup of pgpool-II.  Specifically, I see this in my app server's logs:

[ INFO] 2012-09-04 17:49:47 28647 /mnt/app/shared/bundle/ruby/1.9.1/bin/unicorn [[log_subscriber.rb:105:in `info']] ::   Processing by Api::AccountController#universe as JSON
[ INFO] 2012-09-04 17:49:47 28647 /mnt/app/shared/bundle/ruby/1.9.1/bin/unicorn [[log_subscriber.rb:105:in `info']] ::   Parameters: {"context"=>"{\"agent_id\":0,\"membership_id\":0,\"organization_id\":0,\"workgroup_id\":0,\"channel_ids\":[],\"imh_token\":\"\"}", "_"=>"1346780987727"}
[ INFO] 2012-09-04 17:49:49 28647 /mnt/app/shared/bundle/ruby/1.9.1/bin/unicorn [[log_subscriber.rb:105:in `info']] :: Completed 500 Internal Server Error in 1541ms
[FATAL] 2012-09-04 17:49:49 28647 /mnt/app/shared/bundle/ruby/1.9.1/bin/unicorn [[show_exceptions.rb:133:in `block in log_error']] :: 
ActiveRecord::StatementInvalid (PG::Error: server sent data ("D" message) without prior row description ("T" message): SELECT  "extensions".* FROM "extensions"  WHERE "extensions"."id" = $1 LIMIT 1):

On the pgpool-II end, things look normal:

Sep  4 17:45:58 db1b postgres[27656]: [52-1] 2012-09-04 17:45:58 UTC < cotweet 27656 >LOG:  duration: 0.135 ms  bind a3: SELECT  "extensions".* FROM "extensions"  WHERE "extensions"."id" = $1 LIMIT 1
Sep  4 17:45:58 db1b postgres[27656]: [52-2] 2012-09-04 17:45:58 UTC < cotweet 27656 >DETAIL:  parameters: $1 = '8'
Sep  4 17:45:58 db1b postgres[27656]: [53-1] 2012-09-04 17:45:58 UTC < cotweet 27656 >LOG:  duration: 0.104 ms  bind a3: SELECT  "extensions".* FROM "extensions"  WHERE "extensions"."id" = $1 LIMIT 1
Sep  4 17:45:58 db1b postgres[27656]: [53-2] 2012-09-04 17:45:58 UTC < cotweet 27656 >DETAIL:  parameters: $1 = '17'

I can also run these queries just fine through psql.

I suspect that however the developers of this app have initialized the pg driver for ActiveRecord is wrong and I'll toy with that.  However, has anyone run into this problem with pgpool-II?

I have set PGPool-II  3.2.0 up in master-slave, and load-balancing modes.  The config follows.

# ----------------------------
# pgPool-II configuration file
# ----------------------------
#
# This file consists of lines of the form:
#
#   name = value
#
# Whitespace may be used.  Comments are introduced with "#" anywhere on a line.
# The complete list of parameter names and allowed values can be found in the
# pgPool-II documentation.
#
# This file is read on server startup and when the server receives a SIGHUP
# signal.  If you edit the file on a running system, you have to SIGHUP the
# server for the changes to take effect, or use "pgpool reload".  Some
# parameters, which are marked below, require a server shutdown and restart to
# take effect.
#

# ------------------
# Configured by Chef
# ------------------
#
# Editing this file by hand is useless.
# See /etc/pgpool2/pgpool.conf.sample for detailed comments.

#------------------------------------------------------------------------------
# CONNECTIONS
#------------------------------------------------------------------------------

# - pgpool Connection Settings -

listen_addresses = '*'
port = 5431
socket_dir = '/tmp'

# - pgpool Communication Manager Connection Settings -

pcp_port = 9898
pcp_socket_dir = '/var/run/pgpool'

backend_hostname0 = db1.stg.cotweet.com
backend_port0 = 5432
backend_weight0 = 1
backend_flag0 = 'DISALLOW_TO_FAILOVER'

backend_hostname1 = db1a.stg.cotweet.com
backend_port1 = 5432
backend_weight1 = 1
backend_flag1 = 'DISALLOW_TO_FAILOVER'

backend_hostname2 = db1b.stg.cotweet.com
backend_port2 = 5432
backend_weight2 = 1
backend_flag2 = 'DISALLOW_TO_FAILOVER'

# - Authentication -

enable_pool_hba = on
authentication_timeout = 20

# - SSL Connections -

ssl = off

#------------------------------------------------------------------------------
# POOLS
#------------------------------------------------------------------------------

# - Pool size -

num_init_children = 10
max_pool = 40

# - Life time -

child_life_time = 600
child_max_connections = 0
connection_life_time = 0
client_idle_limit = 0

#------------------------------------------------------------------------------
# LOGS
#------------------------------------------------------------------------------

# - Where to log -

log_destination = 'syslog'

# - What to log -

print_timestamp = on
log_connections = on
log_hostname = off
log_statement = off
log_per_node_statement = on
log_standby_delay = 'if_over_threshold'

# - Syslog specific -

syslog_facility = 'LOCAL0'
syslog_ident = 'pgpool'

# - Debug -

debug_level = 0

#------------------------------------------------------------------------------
# FILE LOCATIONS
#------------------------------------------------------------------------------

pid_file_name = '/var/run/pgpool/pgpool.pid'
logdir = '/var/log/pgpool'

#------------------------------------------------------------------------------
# CONNECTION POOLING
#------------------------------------------------------------------------------

connection_cache = on
reset_query_list = 'ABORT; DISCARD ALL'

#------------------------------------------------------------------------------
# REPLICATION MODE
#------------------------------------------------------------------------------

replication_mode = off
#replicate_select = off
#insert_lock = on
#lobj_lock_table = ''

# - Degenerate handling -

#replication_stop_on_mismatch = off
#failover_if_affected_tuples_mismatch = off

#------------------------------------------------------------------------------
# LOAD BALANCING MODE
#------------------------------------------------------------------------------

load_balance_mode = on
ignore_leading_white_space = on
white_function_list = ''
black_function_list = 'nextval,setval'

#------------------------------------------------------------------------------
# MASTER/SLAVE MODE
#------------------------------------------------------------------------------

master_slave_mode = on
master_slave_sub_mode = 'stream'

# - Streaming -

sr_check_period = 10
sr_check_user = 'user'
sr_check_password = 'password'
delay_threshold = 2097152

# - Special commands -

#follow_master_command = ''

#------------------------------------------------------------------------------
# PARALLEL MODE
#------------------------------------------------------------------------------

parallel_mode = off
#pgpool2_hostname = ''

# - System DB info -

#system_db_hostname  = 'localhost'
#system_db_port = 5432 
#system_db_dbname = 'pgpool'
#system_db_schema = 'pgpool_catalog'
#system_db_user = 'pgpool'
#system_db_password = ''

#------------------------------------------------------------------------------
# HEALTH CHECK
#------------------------------------------------------------------------------

health_check_period = 15
health_check_timeout = 10
health_check_user = 'user'
health_check_password = 'password'
health_check_max_retries = 3
health_check_retry_delay = 1

#------------------------------------------------------------------------------
# FAILOVER AND FAILBACK
#------------------------------------------------------------------------------

#failover_command = ''
#failback_command = ''
#fail_over_on_backend_error = off

#------------------------------------------------------------------------------
# ONLINE RECOVERY
#------------------------------------------------------------------------------

#recovery_user = 'nobody'
#recovery_password = ''
#recovery_1st_stage_command = ''
#recovery_2nd_stage_command = ''
#recovery_timeout = 90
#client_idle_limit_in_recovery = 0

#------------------------------------------------------------------------------
# WATCHDOG
#------------------------------------------------------------------------------
use_watchdog = on 
trusted_servers = 'default-router,db1.stg.cotweet.com,db1a.stg.cotweet.com,db1b.stg.cotweet.com'
delegate_IP = '1.1.1.1'
#wd_hostname = ''
wd_port = 9000
wd_interval = 10
ping_path = '/bin'
ifconfig_path = '/sbin'
if_up_cmd = 'ifconfig eth0:0 inet $_IP_$ netmask 255.255.255.255'
if_down_cmd = 'ifconfig eth0:0 down'
arping_path = '/usr/bin'
arping_cmd = 'arping -U $_IP_$ -w 1'
wd_life_point = 3
wd_lifecheck_query = 'SELECT 1'

# Other pgpool Connection Settings

other_pgpool_hostname0 = db1a.stg.cotweet.com
other_pgpool_port0 = 5431
other_wd_port0 = 9000

#------------------------------------------------------------------------------
# OTHERS
#------------------------------------------------------------------------------

relcache_expire = 0
relcache_size = 256
check_temp_table = on

#------------------------------------------------------------------------------
# ON MEMORY QUERY MEMORY CACHE
#------------------------------------------------------------------------------

memory_cache_enabled = on
memqcache_method = 'memcached'
memqcache_memcached_host = localhost
memqcache_memcached_port = 11211
memqcache_expire = 300
memqcache_auto_cache_invalidation = on
memqcache_maxcache = 409600
memqcache_cache_block_size = 1048576
memqcache_oiddir = '/var/log/pgpool/oiddir'
white_memqcache_table_list = ''
black_memqcache_table_list = ''

ExactTarget
Greg Swallow
System Administrator
Phone | 317 524-5250
Yahoo IM | gswallow01
Email  | gswallow at exacttarget.com

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