manage schema cache when horizontally scaled (closes #1182) #1574
Conversation
|
Review app for commit 428f70d deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
|
We should add tests for this? Will require some interesting black magic from @shahidhk @arvi3411301 I think ;) |
| -> UserInfo -> SchemaCache -> HTTP.Manager | ||
| -> RQLQuery -> m (BL.ByteString, SchemaCache) | ||
| runQuery pool isoL userInfo sc hMgr query = do | ||
| runQuery pool isoL serverId userInfo sc hMgr query = do |
There was a problem hiding this comment.
Should return (BL.ByteString, Maybe (SchemaCache, Timestamp). Just (SC, TS) implies that the schemacache has to be replaced. After this we don't have to use queryNeedsReload in the locations where runQuery is being called.
server/src-rsr/initialise.sql
Outdated
| @@ -403,3 +403,32 @@ CREATE TABLE hdb_catalog.remote_schemas ( | |||
| definition JSON, | |||
| comment TEXT | |||
| ); | |||
|
|
|||
| CREATE TABLE hdb_catalog.hdb_cache_update_event ( | |||
There was a problem hiding this comment.
We are recording schema updates. So let's call it hdb_schema_update_event (cascade the changes through out the PR).
| -- Postgres notification handler | ||
| notifyHandler notif = do | ||
| let eventChannel = PGChannel $ bsToTxt $ PQ.notifyRelname notif | ||
| when (eventChannel == pgChannel) $ |
| onError e = do | ||
| logError logger threadType $ TEQueryError e | ||
| -- Push a listen failed event to queue | ||
| STM.atomically $ STM.writeTQueue eventsQueue CUEListenFail |
There was a problem hiding this comment.
Don't emit a 'listen error' event. Emit an event once the connection is re-established after an error. You'll probably need to expose this functionality from pg-client-hs, probably listen can take something like this as an argument:
data NotifyHandler
= NotifyHandler
{ _ehOnInit :: IO ()
, _ehOnMessage :: Notify -> IO ()
}| cacheUpdateEventProcessor pool logger httpManager eventsQueue | ||
| cacheRef lk serverId cacheInit = do | ||
| -- Initiate previous event IO reference | ||
| prevEventRef <- IORef.newIORef Nothing |
There was a problem hiding this comment.
You don't have to store the previous event ref after the above suggested change (emit event on reconnection).
Resolve Conflicts: server/src-exec/Main.hs server/src-lib/Hasura/Server/Init.hs
Resolve Conflicts: server/src-exec/Main.hs server/src-exec/Ops.hs server/src-lib/Hasura/Server/App.hs server/src-lib/Hasura/Server/Init.hs server/src-lib/Hasura/Server/Query.hs server/src-rsr/migrate_from_9_to_10.sql
|
Review app for commit 933b734 deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
|
Review app for commit e9c7c2b deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
|
Review app for commit 1632dd1 deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
|
Review app for commit bf30119 deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
…l-engine into issue-1182-cache-update
|
Review app for commit 054b26a deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
|
Review app for commit 4472a21 deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
|
Review app for commit 6338341 deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
|
Review app for commit 4a74839 deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
|
Review app for commit 524bf91 deployed to Heroku: https://hge-ci-pull-1574.herokuapp.com |
|
Review app https://hge-ci-pull-1574.herokuapp.com is deleted |
Description
What component does this PR affect?
Requires changes from other components? If yes, please mark the components:
Related Issue
close #1182
Solution and Design
pg-client-hshas been updated to expose a function that helps listen topostgresnotifications over achannelin this PRhdb_catalog.hdb_cache_update_eventwhenever any/v1/query(that changes metadata) is requested. A trigger notifies acache updateevent viahasura_cache_updatechannellistenerandprocessor. Thelistenerthread listens to events onhasura_cache_updatechannel and pushed into aQueue. Theprocessorthread fetches events from thatQueueand processes it. Thus server rebuilds schema cache from database and updates.Type
Checklist: