You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@hive.apache.org by "Daniel Dai (JIRA)" <ji...@apache.org> on 2019/05/07 00:28:00 UTC
[jira] [Created] (HIVE-21697) Remove periodical full refresh in HMS
cache
Daniel Dai created HIVE-21697:
---------------------------------
Summary: Remove periodical full refresh in HMS cache
Key: HIVE-21697
URL: https://issues.apache.org/jira/browse/HIVE-21697
Project: Hive
Issue Type: Improvement
Components: Standalone Metastore
Reporter: Daniel Dai
Assignee: Daniel Dai
In HIVE-18661, we added periodical notification based refresh in HMS cache. We shall remove periodical full refresh to simplify the code as it will no longer be used. In the mean time, we introduced mechanism to provide monotonic reads through the CachedStore.commitTransaction. This will no longer be needed after HIVE-21637. So I will remove related code as well. This will provide some performance benefits include:
1. We don't have to slow down write to catch up notification logs. Write can be done immediately and tag the cache with writeids
2. We can read from cache even if updateUsingNotificationEvents is running. Read will compare the writeids of the cache so monotonic reads will be guaranteed
I'd like to put a patch separately with HIVE-21637 so it can be tested independently. HMW will use periodical notification based refresh to update cache. And it will temporarily lift the monotonic reads guarantee until HIVE-21637 checkin.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)