Currently running a simple sinatra app, using passenger, and using pgbouncer for connection pooling to a database on the same server as the app. Currently I am intermittently getting a PG error that the prepared statement "a\d" doesn't exist.
A PG::Error occurred in #: ERROR: prepared statement "a2" does not exist
the ruby code that is executed before the error
def self.get_ownership_record(id, key)
self.where("user_id=? AND key=?", id, key ).first
end
pgbouncer config
; ######################################################### ; ############# SECTION HEADER [DATABASES] ################ ; ######################################################### [databases] fakedatabase=fake [pgbouncer] ; ----- Generic Settings -------------------------- ; ------------------------------------------------- logfile=/opt/local/var/log/pgbouncer/pgbouncer.log pidfile=/opt/local/var/run/pgbouncer/pgbouncer.pid listen_addr=* listen_port=5444 ; unix_socket_dir=/tmp user=_webuser auth_file=/Users/Shared/data/global/pg_auth auth_type=trust pool_mode=transaction ; max_client_conn=100 ; default_pool_size=20 ; reserve_pool_size=0 ; reserve_pool_timeout=5 ; server_round_robin=0 ; ----- Log Settings ------------------------------ ; ------------------------------------------------- ; syslog=0 ; syslog_ident=pgbouncer ; syslog_facility=daemon ; log_connections=1 ; log_disconnections=1 ; log_pooler_errors=1 ; ----- Console Access Control -------------------- ; ------------------------------------------------- admin_users=admin,nagios ; ------------------------------------------------- ; server_reset_query=DISCARD ALL; server_check_delay=0 server_check_query=SELECT 1; ; server_lifetime=3600 ; server_idle_timeout=600 ; server_connect_timeout=600 ; server_login_retry=15
Is my only solution, to turn off prepared statements?
database.yml
production: adapter: postgresql database: fakedatabase username: admin host: localhost port: 5444 reconnect: true prepared_statements: false
EDIT
I have updated the pgbouncer.ini to use session pooling
pool_mode=session
and uncommented
server_reset_query=DISCARD ALL;
and I am still seemingly, randomly getting errors involving prepared statements, but this time
An ActiveRecord::StatementInvalid occurred in #: PG::Error: ERROR: bind message supplies 2 parameters, but prepared statement "a1" requires 0
I have turned on statement level logging in my postgresql logs and will report back with more details if possible.
follwing Richard Huxton advice, and after some trial and error.
my final setup looks like
database.yml
had to set prepared_statements to true
production: adapter: postgresql database: fakedatabase username: admin host: localhost port: 5444 reconnect: true prepared_statements: true
pgbouncer.ini
had to uncomment server_reset_query=DISCARD ALL;
and set pool_mode=session
; ######################################################### ; ############# SECTION HEADER [DATABASES] ################ ; ######################################################### [databases] fakedatabase=fake [pgbouncer] ; ----- Generic Settings -------------------------- ; ------------------------------------------------- logfile=/opt/local/var/log/pgbouncer/pgbouncer.log pidfile=/opt/local/var/run/pgbouncer/pgbouncer.pid listen_addr=* listen_port=5444 ; unix_socket_dir=/tmp user=_webuser auth_file=/Users/Shared/data/global/pg_auth auth_type=trust pool_mode=session ; max_client_conn=100 ; default_pool_size=20 ; reserve_pool_size=0 ; reserve_pool_timeout=5 ; server_round_robin=0 ; ----- Log Settings ------------------------------ ; ------------------------------------------------- ; syslog=0 ; syslog_ident=pgbouncer ; syslog_facility=daemon ; log_connections=1 ; log_disconnections=1 ; log_pooler_errors=1 ; ----- Console Access Control -------------------- ; ------------------------------------------------- admin_users=admin,nagios ; ------------------------------------------------- server_reset_query=DISCARD ALL; server_check_delay=0 server_check_query=SELECT 1; ; server_lifetime=3600 ; server_idle_timeout=600 ; server_connect_timeout=600 ; server_login_retry=15
basically allow prepared statements in a session pool mode with the default server reset query.
Perhaps reading the FAQ would help? Unless you have a good reason not to, session-pooling should be sensible.
You can use transaction pooling, provided that you PREPARE and EXECUTE the prepared query inside the same transaction (to avoid pgBouncer running the server_reset_query in between).
In my case access to postgres directory and run "DEALLOCATE ALL" resolve the problem.
If you use heroku, like this
> heroku pg:psql -a app_name
app_name::DATABASE=> DEALLOCATE ALL
来源：https://stackoverflow.com/questions/20150503/prepared-statement-doesnt-exist