Hi Chris,
I have the connection pool defined in /etc/tomcat8/context.xml. Is that the
wrong place the define it? Is what is defined there being copied into each
application? I underplayed some sample application and I am now seeing 10 time
the number of apps being deployed DB connections.
I am creating war files from eclipse to be deployed. Should I be creating a
context file in eclipse so that it is included in the war file? If yes, should
I copy the context.xml from from /etc/tomcat8 and then remove the pool
definition from that file and just have it in the one in the war file?
Responses to the questions are below.
I have also implemented what Filip recommended, however after 24 hours the app
start intermittently failing and there are only 2 open connections to the DB.
This is in the log:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet
successfully received from the server was 79,290,702 milliseconds ago. The
last packet sent successfully to the server was 79,290,702 milliseconds ago. is
longer than the server configured value of 'wait_timeout'. You should consider
either expiring and/or testing connection validity before use in your
application, increasing the server configured values for client timeouts, or
using the Connector/J connection property 'autoReconnect=true' to avoid this
problem.
12-Jun-2015 16:51:55.659 WARNING [Tomcat JDBC Pool
Cleaner[147643626:1434048550658]]
org.apache.tomcat.jdbc.pool.ConnectionPool.abandon Connection has been
abandoned
PooledConnection[com.mysql.jdbc.JDBC4Connection@1fa3cd0e]:java.lang.Exception
79,290,702 milliseconds is ~22 hours if my calculations are correct. That is
way way longer than what is specified.
Here is what I added:
logAbandoned=true
removeAbandoned=true
removeAbandonedTimeout=60
timeBetweenEvictionRunsMillis=15000
Thanks,
Doug
On Jun 12, 2015, at 4:07 PM, Christopher Schultz
ch...@christopherschultz.net wrote:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256
Douglas,
In addition to what Filip posted...
On 6/11/15 12:18 PM, Douglas Schaible wrote:
Good Day All,
I am having a problem with a connection pool and I was hoping for
some guidance.
I have defined the connection pool below for two deployed
applications to use. When I bounce the server I can see that it
immediately crates 100 connections to the DB. (I am ok with this,
but that is not what is specified in the config).
When you start your application, does it load a bunch of stuff from
the database? If you are fetching lots of connections and not
returning them, you may see your connection count go up to 100 (the
maxTotal value).
No, it does not. Both of the apps on the server only make connections to the
DB in doGet and they do not have an init method.
Then when I access the application repeatedly very quickly new
connections to the DB are created each time a page is called till
it reaches about 150 and then future calls fail with the message
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException:
Too many connections” logged by the server.
I would have expected the pool to stop handing-out connections at 100.
But, if you don't have removeAbandoned and you aren't returning the
connections properly, then the pool is full of connections that can't
be used.
The server will make more than 100 connections, it will make about 150 and then
start giving the error.
If we don’t place any extra load on the server the number of
connections to the DB are reduced to 1 or 2 after 24 hours and you
get the error Timeout: Pool empty. Unable to fetch a connection
in 30 seconds, none available[size:100; busy:100; idle:0;
lastwait:3].” from one of the applications and the other
application continues to work just fine.
The other application likely is using a different pool. Where is that
Resource defined?
it uses the same pool. The pool is defined in /etc/tomcat8/context.xml. There
is only one Resource
I believe that the DB, MySQL, is dropping the connection, but
tomcat does not know that it has been dropped.
I am looking for some guidance on how to tune this configuration.
Any suggestions?
Resource name=jdbc/PDB auth=Container
type=javax.sql.DataSource
factory=org.apache.tomcat.jdbc.pool.DataSourceFactory
initialSize=10 maxTotal=100 maxIdle=5 maxWaitMillis=1
username=“xx password=“xx
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://x.xx.us-east-1.rds.amazonaws.com”/
Your error message says Unable to fetch a connection in 30 seconds,
but your maxWaitMillis is 1 (10 seconds). Are you sure this is the
configuration being used?
Yes. I am not sure why the timeout is different or more connections are made
than expected. If I removed the configuration from context.xml and bounce the
server all of the connection attempts the DB fail, so I believe that config is
being used
