> On Thu, Aug 13, 2015 at 1:37 PM, Melvin Davidson <melvin6...@gmail.com> wrote:
> On Thu, Aug 13, 2015 at 3:49 PM, Jeff Janes <jeff.ja...@gmail.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. >> >> 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. > Sure I did, 9.4. OS would be Linux, although I would hope a solution would be work. If you mean the built-in-to-core rules or triggers, those wouldn't work. Neither one allows you to rewrite a where clause as far as I can tell. Rules allows you add one, but not more than that. And triggers don't exists for select queries. Cheers, Jeff
