Sporadic 500 errors when running Bitbucket Server - Database connection timeouts
- 500 errors are sporadically returned when visiting Bitbucket Server in a web browser
- Bitbucket Server web pages don't always render fully (missing data or sections)
- When pulling from, pushing or cloning to Bitbucket Server, it responds with the error code 500 intermittently
$ git pull origin master fatal: unable to access 'http://10.23.165.46/bitbucket/scm/project/repo.git/': The requested URL returned error: 500 $ git pull origin master From http://10.23.165.46/bitbucket/scm/project/repo.git/ * branch master -> FETCH_HEAD Already up-to-date.
Look at the
The exceptions can happen anytime Bitbucket Server uses the database. They should always have a database-related cause and the cause may indicate that the database connection was closed. See below for some examples.
2013-10-08 13:21:37,909 ERROR [http-bio-7990-exec-256] 801x6305x1 10.23.172.120,0:0:0:0:0:0:0:1 "GET /mvc/error500 HTTP/1.1" c.a.s.i.web.ErrorPageController There was an unhandled exception loading [/scm/project/repo.git/info/refs] org.springframework.transaction.TransactionSystemException: Could not roll back Hibernate transaction; nested exception is org.hibernate.TransactionException: rollback failed ... Caused by: org.hibernate.TransactionException: rollback failed ... Caused by: org.hibernate.TransactionException: unable to rollback against JDBC connection ... Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: The connection is closed.
ERROR [http-bio-7990-exec-2442] 19x26849x1 18.104.22.168,127.0.0.1 "GET /mvc/error500 HTTP/1.1" c.a.s.i.web.ErrorPageController There was an unhandled exception loading [/scm/ffa/devflow.git/info/refs] org.springframework.transaction.CannotCreateTransactionException: Could not open Hibernate Session for transaction; nested exception is org.hibernate.TransactionException: JDBC begin transaction failed: ... ... Caused by: org.hibernate.TransactionException: JDBC begin transaction failed: ... ... Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet successfully received from the server was 197,409 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago. ... Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
Bitbucket Server does a periodic "ping" (a throwaway operation on the database that doesn't update any data) to keep the server from closing the connection as being idle. However, if the database server has aggressive timeouts configured, Bitbucket Server's default heartbeat ping may not be fast enough. That can result in connections in the pool being closed. That, in turn, causes random operations to fail when the connection they get from the pool (all of which are expected to be open) is already closed.
You can either have Bitbucket Server ping the database more frequently or increase the connection timeout.
Option 1) Tweak heartbeat rate on Bitbucket Server
This solution will work for all databases. Increase the heartbeat rate by add the following parameter to
That will cause Bitbucket Server to heartbeat its database connections every minute instead of every 10 minutes (the default), avoiding connections in the pool from being closed by the remote server.
Option 2) Tweak database connection timeout parameter
This solution requires a different solution for each database:
The following command on a MySQL instance will reveal timeout parameters:
mysql> SHOW GLOBAL VARIABLES LIKE '%timeout%'; +----------------------------+-------+ | Variable_name | Value | +----------------------------+-------+ | connect_timeout | 10 | | delayed_insert_timeout | 300 | | innodb_lock_wait_timeout | 60 | | innodb_rollback_on_timeout | OFF | | interactive_timeout | 28800 | | net_read_timeout | 30 | | net_write_timeout | 30 | | slave_net_timeout | 3600 | | table_lock_wait_timeout | 50 | | wait_timeout | 180 | +----------------------------+-------+
On thread startup, the session wait_timeout value is initialized from the global
wait_timeout value or from the global interactive_timeout value, depending on the type of client (as defined by the CLIENT_INTERACTIVE connect option to mysql_real_connect()).
If your MySQL server is using
wait_timeout = 180 (seconds) - 3 minutes - as a timeout for our DB connection created from Bitbucket Server and Bitbucket Server is configured with the default db.pool.idle.testInterval = 10 (minutes) set up as its keep alive the connection will be dropped out very often causing the exceptions above.