Re: How different is AWS-RDS postgres?

Unless something has changed in recent years, the core servlet engine of
tomcat IS catalina. Embedded tomcat is embedded catalina. It looks like
the I/O error is a result of attempting to send a query on an already dead
connection. I'd look for something that is limiting how long a connection
can be open - either an explicit or default value for a timeout in the
connection pool or on the server side. If you don't get the same behaviour
when running against a database locally, I'd definitely look at the default
settings in RDS. It may be automatically closing connections if they are
idle for even a brief period.

On Thu, May 27, 2021 at 3:35 PM Rob Sargent <robjsargent(at)gmail(dot)com> wrote:

> On 5/27/21 4:25 PM, Sam Gendler wrote:
>
> That sure looks like something is causing your connection to have a
> transaction rollback. I haven't worked in Java in far too long, but it
> seems like your connection pool is under the impression your connection was
> abandoned so it reclaims it and rollback the transaction, which would
> explain why you aren't seeing the table when all is said and done - all of
> the work is being undone at the end.
>
> One possibility, based on the catalina log you provided - if you have
> either end of the connection set up to automatically close idle connections
> after a period of time, then you might receive a closed connection from the
> pool, which will just error out when you attempt to run a query. In which
> case, you need to set up your connection pool to test a connection before
> it returns it to the requester. Usually something as simple as "select 2"
> will be sufficient to determine if the database connection is open. I can
> just about guarantee that your connection pool has a parameter which allows
> you to specify a query to execute when a connection is requested.
>
>
> Well I /was/ doing
>
> contextResource.setProperty("validationQuery",
> "SELECT 1");
>
> but I see that I lost that when I switched to using a properties file.
> Thanks for point me there.
>
> The loop of 16 insert statement is in a single transaction, single
> connection so I'm not sure who's choking first. Is the connection idle
> after the I/O error or is the I/O error from a dead connection? (Small
> disclaimer: there is no catalina involved here, just an embedded tomcat
> instance.)
>
>
>
>
>