Author Topic: Queries during hook_civicrm_post (Read 575 times)

samknelson · September 10, 2015, 06:08:53 am

I'm hoping for a little bit of guidance.

The objective: when a Individual is registered for an Event, I want to add an Activity attached to the *Organization* with which that Individual is associated. (The idea being that you can go to an Organization's record and see registration Activities for all it's employees.)

My original plan had been to implement this logic during hook_civicrm_post. When I detected a "create" operation on an object of type "Participant", I'd run some checks and then insert my own activity.

But I'm running into a number of issues, some of which I think are deadlocks. In particular, if I try to run a query against the Contacts table during hook_civicrm_post, the web page never returns; I assume what's going on is that I'm trying to query against a table that's still in the middle of a transactional update.

So, a couple of questions:

- What's the lifecycle of hook_civicrm_post? The documentation says that it's called "after a db write", but is there still a transaction active? Is there any way to safely query the database during this hook?

- Or, is my entire approach wrong? Should I be doing this some other way?

Thank you!

totten · September 10, 2015, 12:32:43 pm

Yeah, there should usually be an on-going transaction during hook_post. If the hook generates an error, it would be possible to rollback everything.

I've had one or two situations where I encountered a similar issue and worked around the deadlocks by deferring work until after the transaction. This generally looks like:

Code: [Select]

<?php
CRM_Core_Transaction::addCallback(CRM_Core_Transaction::PHASE_POST_COMMIT, function(){
  // Do the subsequent DB work.
});

You might want to take a little extra care to handle error-conditions within the callback.

Aside: There's some more material about transaction management at http://wiki.civicrm.org/confluence/display/CRMDOC/Transaction+Reference

samknelson · September 11, 2015, 07:20:00 am

Thank you! addCallback() is just what I was looking for.

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Author Topic: Queries during hook_civicrm_post (Read 575 times)

samknelson

Queries during hook_civicrm_post

totten

Re: Queries during hook_civicrm_post

samknelson

Re: Queries during hook_civicrm_post