sorry for the very vague report - but these symtoms are all that we have at the moment.

when the server is on high load, it sometimes happens that (after a node save) an empty node is served by memcache, while in the database the correct field values are still available. the node title is not empty.

we are using PECL memcache 2.2.6 (as recommended here)

does anyone have hints, what the error could be - or maybe hints how we could debug this better (our problem is also that is happens just sometimes)

thanks und best,
walter

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#4 m.txt13.07 KBvalderama

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valderama’s picture

valderama commented

we currently try to keep field cache in the DB - and see if that helps..

slashrsm’s picture

slashrsm commented

I can confirm this problem. It happened to me also.

When we saved a node everything was saved OK to DB. cache_field was not updated, though. The node was displayed unchanged because of that. When I moved cache_field bin back to MySQL everything looks fine.

We are using:
- Drupal 7.14
- Memcache integration 7.x-1.0 with this patch http://drupal.org/node/872338#comment-5525296
- PHP 5.3.2
- Memcache extension 3.0.4

slashrsm’s picture

slashrsm commented

See comments in http://www.php.net/manual/en/memcache.delete.php

It looks like there could be problems with older versions of memcached. Which version do you use? I'll try to upgrade today and we'll see what happens.

valderama’s picture

valderama commented
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new m.txt13.07 KB

We are using PECL memcache 2.2.6 and memcached 1.4.5 -- I'll try to test if Memcache::delete should work with this combination later.

BTW, using the DB for cache_field did not help in our case.

I also attached a list of enabled modules, as I am not sure if another contrib module could interfere.

slashrsm’s picture

slashrsm commented

Now I tested in production with latest Memcached (1.4.13) and I still have the same problem. I do not have it on my dev machine, so it could be a problem in PECL extension or PHP version. I have Memcache extension 3.0.4 on production and 3.0.6 on my machine.

Will test further and see what happens.

slashrsm’s picture

slashrsm commented

I found the reason for my problem: http://janezurevc.name/strange-behaviour-race-condition-during-nodesave

slashrsm’s picture

slashrsm commented
Priority: Normal » Major

It looks like this problem can occur on any Drupal site using Memcached for cache_field. It is more likely for high-traffic sites, but anyway. Rising priority to major...

Referencing related core issue: #1677830: Node not saved when hook_node_insert() or hook_node_update() are invoked

slashrsm’s picture

slashrsm commented

Another related issue: #1679344: Race condition in node_save() when not using DB for cache_field

marcingy’s picture

marcingy commented
Assigned: Unassigned » marcingy

Grabbing I'll try and post some solutions to this over the weekend as I have been bitten by this bug, and we have a working solution for our use case (based on queues) and after reading the blog post there could be a better way to achieve the same thing. We just didn't realise it was wider issue and put it down too our site is strange (because it is).

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marcingy commented
Issue summary: View changes

changed the text

jeremy’s picture

jeremy commented
Issue summary: View changes
Status: Active » Fixed

Please be sure to install the latest Drupal memcache module, and to configure properly as described in README.txt. Much work has been done to ensure consistency and accuracy in the caching layer.

Status: Fixed » Closed (fixed)

Automatically closed - issue fixed for 2 weeks with no activity.