GraphQL performing INSERT on cache_discovery table

[d0190535]

Hi all,

We have a drupal site which acts as graphql api endpoint and during heavy loads (about 17 graphql requests/sec), our site seems to go down and the bottleneck appears to be graphql doing a lot of INSERTs to the cache_discovery table.

Does anyone know if this is a drupal core feature or can we disable this just for graphql? I am thinking this might not needed as we will have varnish cache and will be using persisted queries.

Thanks

[fubhy]

Can you figure out what kind of data is being inserted? This should not happen. The cache_discovery table is a cache bin from Drupal core and is used for stuff like cached plugin definitions, etc.

[fubhy]

If the data that is getting written is graphql plugin information then it sounds like your modules are somehow generating request-based cache metadata for these plugins which should not happen and honestly doesn't sound like it would be something triggered by this module itself.

[fubhy]

Please also always specify which version of this module you are referring to.

[d0190535]

Hi fubhy, thanks for the details!

I am trying to get the logs to see what type of data it is trying to insert, but I suspect that it performs an INSERT because we are constantly making the route('path') graphql api call, which returns us the entire markup of the page. And to build the markup of the page, it involves views and other plugins, which then caused the INSERT to the discovery table.

Could that be why? We are using version 8.x-3.0-rc3. Thanks again

[d0190535]

@fubhy I was able to pull the log and on a graphql request it attemps to do the following INSERT:

"GET /graphql?queryId=8056692b8b0d9187fedd512766c2b2ed2964b4df:1&variables=%7B%22id%22:%228346%22,%22lang%22:%22EN_GB%22%7D&units.temperature=celsius&units.distance=kilometer&AQI=US&language=en HTTP/1.1" 500 68 "https://localhost.dev.com/usa/montana/belgrade" "Mozilla/5.0 (Linux; Android 9; MRD-LX1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.111 Mobile Safari/537.36" vhost=localhostdrupal8.dev.acquia-sites.com host=localhost.dev.com hosting_site=drupal8 pid=7366 request_time=124031314 forwarded_for="xxx.xxx.xx.xxx, xxx.xx.xx.xxx" request_id="v-889920f2-857c-11ea-b295-e74794d9bb2c" location="-"
[23-Apr-2020 09:09:22 America/Los_Angeles] Uncaught PHP Exception Drupal\Core\Database\DatabaseExceptionWrapper: "SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction: INSERT INTO {cache_discovery} (cid, expire, created, tags, checksum, data, serialized) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6) ON DUPLICATE KEY UPDATE cid = VALUES(cid), expire = VALUES(expire), created = VALUES(created), tags = VALUES(tags), checksum = VALUES(checksum), data = VALUES(data), serialized = VALUES(serialized); Array
(
    [:db_insert_placeholder_0] => last_write_timestamp_cache_discovery
    [:db_insert_placeholder_1] => -1
    [:db_insert_placeholder_2] => 1587658090.031
    [:db_insert_placeholder_3] =>
    [:db_insert_placeholder_4] => 0
    [:db_insert_placeholder_5] => d:1587658090.0320001;
    [:db_insert_placeholder_6] => 1
)
" at /mnt/www/html/drupal8/docroot/core/lib/Drupal/Core/Database/Connection.php line 692 request_id="v-889920f2-857c-11ea-b295-e74794d9bb2c"

Any idea why it is trying to insert into cache discovery table? Thanks

[d0190535]

@fubhy Do you have any ideas? Those mysterious inserts are causing deadlocks on our app during high usage of GraphQL. Thanks a lot