> Actually I'm was running pgpool on db2 (backend_hostname1) and am now > running it on db3 (backend_hostname2). > I have actually suspected that pgpool might be opting for some sort of > socket connection to the local instance of postgres instead of using the > TCP/IP connection parameters in an effort to speed things up. > > I have done my best to ensure that pgpool has completely separate socket > directories but it wouldn't be hard for pgpool to find a local postgres > socket if it wanted. If I end up with another outage and this time db3 is > the postgres instance that locks up, I'll be fairly certain that this is the > problem but for the moment I can only speculate. > > I'm assuming you're suggesting I set backend_hostname0 = '' because it is > already weighted to 0.0 anyway?
No. Because I thought you are running pgpool on db1. '' means force pgpool to use UNIX domain socket. So if you running pgpool on db3, you could set: backend_hostname2 = '' > I have db1 (backend_hostname0) weighted to 0.0 in an effort to direct all > selects to the two slave hosts (db2 and db3) but still benefit from pgpool > intelligently sending writes to db1. > db1 is the mammoth master host and needs all available i/o to deal with > writes. > My understanding is that this is how "master_slave_mode = true" works. > Writes are always directed to backend_hostname0. > > If I need to reevaluate that thinking, please advise but that has been > working for me for months now. > > thx > -s > > On Thu, Nov 5, 2009 at 9:26 PM, Tatsuo Ishii <[email protected]> wrote: > > > Besides the useless error message from pgp_child(it seems someone > > believed that EOF will set some error number to the global errono > > variable. I will fix this anyway.), for me it seems socket files are > > going dead. I suspect some network stack bugs could cause this but I'm > > not sure. One thing you might want to try is, changing this: > > > > backend_hostname0 = 'db1.xxx.xxx' > > > > to: > > > > backend_hostname0 = '' > > > > This will make pgpool to use UNIX domain socket for the communication > > channel to PostgreSQL, rather than TCP/IP. It may or may not affect > > the problem you have, since the network code in the kernel will be > > different. > > > > (I assume you are running pgpool on db1.xxx.xxx) > > -- > > Tatsuo Ishii > > SRA OSS, Inc. Japan > > > > > Has anyone else run into this: > > > > > > My pgpool instance runs without problems for days on end and then > > suddenly > > > stops responding to all requests. > > > At the same moment, one of my three backend db hosts becomes completely > > > inaccessible. > > > Pgpool will not respond to shutdown, or even kill and must be kill -9'd > > > Once all pgpool processes are out of the way, the inaccessible postgres > > > server once again becomes responsive. > > > I restart pgpool and everything works properly for a few more days. > > > > > > At the moment the problem occurs, pgpool's log output, which typically > > > consists of just connection logging, turns into a steady stream of this: > > > Nov 5 11:33:18 s...@obfuscated pgpool: 2009-11-05 11:33:18 ERROR: pid > > 12811: > > > pcp_child: pcp_read() failed. reason: Success > > > These errors show up sporaticlly in my pgpool logs all the time but don't > > > appear to have any adverse effects until the whole thing takes a dive. > > > I would desperately like to know what this error message is trying to > > tell > > > me. > > > > > > I have not been able to correlate any given query/connection/process to > > the > > > timing of the outages. > > > Sometimes they happens at peak usage periods, sometimes they happen in > > the > > > middle of the night. > > > > > > I experienced this problem using pgpool-II v1.3 and have recently > > upgraded > > > to pgpool-II v2.2.5 but am still seeing the same issue. > > > > > > It may be relevant to point out that I am running pgpool on one of the > > > machines that is also acting as a postgres backend and it is always the > > > postgres instance on the pgpool host that locks up. > > > This morning I moved the pgpool instance onto another one of the postgres > > > backend hosts in an effort to see if the cohabitation of pgpool and > > postgres > > > is causing problems or if there is simply an issue with that postres on > > that > > > host of if this is just a coincidence. > > > I likely won't gain anything from this test for a day or more. > > > > > > Also relevant is that I am running mammoth replicator and am only using > > > pgpool for connection load balancing and high availability. > > > > > > Below is my pgpool.conf. > > > > > > Any thoughts appreciated. > > > > > > -steve crandell > > > > > > > > > > > > f > > > > > > # > > > # pgpool-II configuration file sample > > > # $Header: /cvsroot/pgpool/pgpool-II/pgpool.conf.sample,v 1.4.2.3 > > > 2007/10/12 09:15:02 y-asaba Exp $ > > > > > > # Host name or IP address to listen on: '*' for all, '' for no TCP/IP > > > # connections > > > #listen_addresses = 'localhost' > > > listen_addresses = '10.xxx.xxx.xxx' > > > > > > # Port number for pgpool > > > port = 5432 > > > > > > # Port number for pgpool communication manager > > > pcp_port = 9898 > > > > > > # Unix domain socket path. (The Debian package defaults to > > > # /var/run/postgresql.) > > > socket_dir = '/usr/local/pgpool' > > > > > > # Unix domain socket path for pgpool communication manager. > > > pcp_socket_dir = '/usr/local/pgpool' > > > > > > # Unix domain socket path for the backend. Debian package defaults to > > > /var/run/postgresql! > > > backend_socket_dir = '/usr/local/pgpool' > > > > > > # pgpool communication manager timeout. 0 means no timeout, but > > > strongly not recommended! > > > pcp_timeout = 10 > > > > > > # number of pre-forked child process > > > num_init_children = 32 > > > > > > > > > # Number of connection pools allowed for a child process > > > max_pool = 4 > > > > > > > > > # If idle for this many seconds, child exits. 0 means no timeout. > > > child_life_time = 30 > > > > > > # If idle for this many seconds, connection to PostgreSQL closes. > > > # 0 means no timeout. > > > #connection_life_time = 0 > > > connection_life_time = 30 > > > > > > # If child_max_connections connections were received, child exits. > > > # 0 means no exit. > > > # change > > > child_max_connections = 0 > > > > > > # Maximum time in seconds to complete client authentication. > > > # 0 means no timeout. > > > authentication_timeout = 60 > > > > > > # Logging directory (more accurately, the directory for the PID file) > > > logdir = '/usr/local/pgpool' > > > > > > # Replication mode > > > replication_mode = false > > > > > > # Set this to true if you want to avoid deadlock situations when > > > # replication is enabled. There will, however, be a noticable > > performance > > > # degradation. A workaround is to set this to false and insert a > > /*STRICT*/ > > > # comment at the beginning of the SQL command. > > > replication_strict = false > > > > > > # When replication_strict is set to false, there will be a chance for > > > # deadlocks. Set this to nonzero (in milliseconds) to detect this > > > # situation and resolve the deadlock by aborting current session. > > > replication_timeout = 5000 > > > > > > # Load balancing mode, i.e., all SELECTs except in a transaction block > > > # are load balanced. This is ignored if replication_mode is false. > > > # change > > > load_balance_mode = true > > > > > > # if there's a data mismatch between master and secondary > > > # start degeneration to stop replication mode > > > replication_stop_on_mismatch = false > > > > > > # If true, replicate SELECT statement when load balancing is disabled. > > > # If false, it is only sent to the master node. > > > # change > > > replicate_select = true > > > > > > # Semicolon separated list of queries to be issued at the end of a > > session > > > reset_query_list = 'ABORT; RESET ALL; SET SESSION AUTHORIZATION DEFAULT' > > > > > > # If true print timestamp on each log line. > > > print_timestamp = true > > > > > > # If true, operate in master/slave mode. > > > # change > > > master_slave_mode = true > > > > > > # If true, cache connection pool. > > > connection_cache = false > > > > > > # Health check timeout. 0 means no timeout. > > > health_check_timeout = 20 > > > > > > # Health check period. 0 means no health check. > > > health_check_period = 0 > > > > > > # Health check user > > > health_check_user = 'nobody' > > > > > > # If true, automatically lock table with INSERT statements to keep SERIAL > > > # data consistency. An /*INSERT LOCK*/ comment has the same effect. A > > > # /NO INSERT LOCK*/ comment disables the effect. > > > insert_lock = false > > > > > > # If true, ignore leading white spaces of each query while pgpool judges > > > # whether the query is a SELECT so that it can be load balanced. This > > > # is useful for certain APIs such as DBI/DBD which is known to adding an > > > # extra leading white space. > > > ignore_leading_white_space = false > > > > > > # If true, print all statements to the log. Like the log_statement > > option > > > # to PostgreSQL, this allows for observing queries without engaging in > > full > > > # debugging. > > > log_statement = false > > > > > > # If true, incoming connections will be printed to the log. > > > # change > > > log_connections = true > > > > > > # If true, hostname will be shown in ps status. Also shown in > > > # connection log if log_connections = true. > > > # Be warned that this feature will add overhead to look up hostname. > > > log_hostname = false > > > > > > # if non 0, run in parallel query mode > > > parallel_mode = false > > > > > > # if non 0, use query cache > > > enable_query_cache = 0 > > > > > > #set pgpool2 hostname > > > 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 = '' > > > > > > # backend_hostname, backend_port, backend_weight > > > # here are examples > > > backend_hostname0 = 'db1.xxx.xxx' > > > backend_port0 = 5433 > > > backend_weight0 = 0.0 > > > > > > backend_hostname1 = 'db2.xxx.xxx' > > > backend_port1 = 5433 > > > backend_weight1 = 0.4 > > > > > > backend_hostname2 = 'db3.xxx.xxx' > > > backend_port2 = 5433 > > > backend_weight2 = 0.6 > > > > > > > > > > > > # - HBA - > > > > > > # If true, use pool_hba.conf for client authentication. In pgpool-II > > > # 1.1, the default value is false. The default value will be true in > > > # 1.2. > > > enable_pool_hba = false > > _______________________________________________ Pgpool-general mailing list [email protected] http://pgfoundry.org/mailman/listinfo/pgpool-general
