Re: Extension to rewrite queries before execution

You have not stated which Version or PostgreSQL, nor the O/S involved. That
being said, depending on what the specific query is, you might consider
using a Rule or Trigger to handle it. If you use a Trigger ( which is the
preferred method) you can also embed "set" commands the associated function.

On Thu, Aug 13, 2015 at 3:49 PM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:

> I am looking for an extension or a technique that will allow me to
> intercept a query by the exact query text, and replace that query with a
> different one.
>
> The context is running a third-party app which issues queries I have no
> control over. I'd like to intercept a specific query (which has no bind
> parameters) and either replace the query text with a different text which,
> for example, swaps out an "in list" clause to instead be an "exists
> (subquery)".
>
> Or just wrap the query in a "set enable_* =off;" or "set work_mem=*;"
> before and a reset of it after.
>
> Is there anything out there like this? This would be for 9.4.
>
> I'm willing to put the query text, and its replacement, directly into the
> extension source code and compile it, but of course something more flexible
> would be ideal.
>
> Thanks,
>
> Jeff
>

--
*Melvin Davidson*
I reserve the right to fantasize. Whether or not you
wish to share my fantasy is entirely up to you.