Hi John,
I am working in spring boot (maven) project.
I am not doing exclusive null-out of the connection feeling that spring boot
will manage it, do I still need to manage it myself?
If you want I can list the dependencies here.
I have just added the following dependency but didn’t try yet on production
server.
<dependency>
<groupId>com.zaxxer</groupId>
<artifactId>HikariCP</artifactId>
<version>2.7.8</version>
<scope>compile</scope>
</dependency>
Regards,
Faisal Zaidi
-----Original Message-----
From: John Dale [mailto:jcdw...@gmail.com]
Sent: Monday, February 18, 2019 5:45 PM
To: Tomcat Users List
Subject: Re: Tomcat connection error
I agree - release your connection, commit transaction (if you have auto-commit
set to false), and null-out your connection references.
The analogy in c++ is you need deallocate memory.
Java has GC in Java at a base level, but we also have some resource reclamation
at higher levels of abstraction over which GC has no purview. Pooling
(threads, connections) is an example. The connection pool needs to reclaim its
connections for reallocation to other threads. If it can't, the application
will hang waiting for connections.
Do you have a static references to a database connection?
The golden rule with database connections is acquire them late and release them
early. I like to create try/catch/finally blocks. In the finally block, which
executes even if there is an exception, I commit the transaction and set
connection reference to null.
As a matter of course, I would null out and close references to
PreparedStatements and ResultSets as well (especially ResultSets).
I'm sure you'll figure it out.
Sincerely,
John
On 2/18/19, Mark Thomas <ma...@apache.org> wrote:
> On 18/02/2019 10:24, fai...@bestercapitalmedia.com wrote:
>> Hi Ted,
>>
>> Yes, you are right.
>> I just need to restart the tomcat to get back it on.
>> There is no need to restart the mySql in my case.
>>
>> Any clue please.
>
> Sounds like a connection leak in the web application. I expect the
> connection pool includes tools to help you track that sort of problem down.
>
> Mark
>
>
>>
>> Faisal Zaidi
>>
>> -----Original Message-----
>> From: Ted Spradley [mailto:ted.k.sprad...@gmail.com]
>> Sent: Monday, February 18, 2019 1:52 PM
>> To: Tomcat Users List
>> Subject: Re: Tomcat connection error
>>
>> Hi Faisal,
>>
>> Your application(s) run as expected for a while, then you get the SQL
>> Connection error? Then the only way to “fix it” is to restart Tomcat?
>> At the same time are you also restarting MySQL?
>>
>> Thanks,
>> Ted
>>
>>> On Feb 18, 2019, at 02:17, Luis Rodríguez Fernández
>>> <uo67...@gmail.com>
>>> wrote:
>>>
>>> Hello Faisal,
>>>
>>> It looks like your problem is more related with your hikari
>>> connection pool than with tomcat itself. I would recommend you to
>>> double check your hikari configuration properties. Pay specially
>>> attention on how you are configuring your connection pool (minimum
>>> and maximum size, timeout,
>>> etc...) It looks like there is "something" in your application that
>>> prevents to get connections from your pool.
>>>
>>> Hope it helps,
>>>
>>> Luis
>>>
>>>
>>>
>>>
>>>
>>>
>>>> El lun., 18 feb. 2019 a las 6:33, <fai...@bestercapitalmedia.com>
>>>> escribió:
>>>>
>>>> Dear all,
>>>>
>>>>
>>>>
>>>> I am working on a project and I am facing following issue on almost
>>>> every second day. I need to restart tomcat to get it running again.
>>>>
>>>> Can someone guide me on it. Ask if you need some other insight to
>>>> look into it.
>>>>
>>>>
>>>>
>>>> 2019-02-18 04:49:35.572 WARN 20698 --- [io-4200-exec-15]
>>>> o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 0, SQLState: null
>>>>
>>>> 2019-02-18 04:49:35.572 ERROR 20698 --- [io-4200-exec-15]
>>>> o.h.engine.jdbc.spi.SqlExceptionHelper : HikariPool-1 - Connection is
>>>> not
>>>> available, request timed out after 30000ms.
>>>>
>>>> 2019-02-18 04:49:35.573 WARN 20698 --- [io-4200-exec-15]
>>>> o.s.s.o.provider.endpoint.TokenEndpoint : Handling error:
>>>> InternalAuthenticationServiceException, Unable to acquire JDBC
>>>> Connection; nested exception is
>>>> org.hibernate.exception.JDBCConnectionException: Unable to acquire
>>>> JDBC Connection
>>>>
>>>>
>>>>
>>>> Server is Ubuntu (aws)
>>>>
>>>> Database is mySql
>>>>
>>>> java version "1.8.0_181"
>>>>
>>>> Java(TM) SE Runtime Environment (build 1.8.0_181-b13)
>>>>
>>>> Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)
>>>>
>>>>
>>>>
>>>> Best Regards | Bien Cordialement | تحياتي
>>>>
>>>> Faisal Zaidi
>>>> Application Architect
>>>>
>>>>
>>>>
>>>>
>>>
>>> --
>>>
>>> "Ever tried. Ever failed. No matter. Try Again. Fail again. Fail
>>> better."
>>>
>>> - Samuel Beckett
>>
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