[
https://issues.apache.org/jira/browse/AURORA-1861?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15750628#comment-15750628
]
David McLaughlin commented on AURORA-1861:
------------------------------------------
Using the mybatis metrics that we just added, we've found that job updates is
(as expected) the biggest offender here (on our clusters the query to get all
updates is upwards of 20 seconds alone - that is 20s inside a global write lock
that effectively means Scheduler downtime). I'd like to start by removing that.
> Remove duplicate Snapshot fields for DB stores
> ----------------------------------------------
>
> Key: AURORA-1861
> URL: https://issues.apache.org/jira/browse/AURORA-1861
> Project: Aurora
> Issue Type: Task
> Components: Scheduler
> Reporter: David McLaughlin
> Assignee: David McLaughlin
>
> Currently we double-write any DB-backed stores into a Snapshot struct when
> creating a Snapshot. This inflates the size of the Snapshot, which is already
> a problem for large production clusters (see AURORA-74).
> Example for LockStore from
> https://github.com/apache/aurora/blob/master/src/main/java/org/apache/aurora/scheduler/storage/log/SnapshotStoreImpl.java:
> {code}
> new SnapshotField() {
> // It's important for locks to be replayed first, since there are
> relations that expect
> // references to be valid on insertion.
> @Override
> public void saveToSnapshot(MutableStoreProvider store, Snapshot
> snapshot) {
>
> snapshot.setLocks(ILock.toBuildersSet(store.getLockStore().fetchLocks()));
> }
> @Override
> public void restoreFromSnapshot(MutableStoreProvider store, Snapshot
> snapshot) {
> if (hasDbSnapshot(snapshot)) {
> LOG.info("Deferring lock restore to dbsnapshot");
> return;
> }
> store.getLockStore().deleteLocks();
> if (snapshot.isSetLocks()) {
> for (Lock lock : snapshot.getLocks()) {
> store.getLockStore().saveLock(ILock.build(lock));
> }
> }
> }
> },
> {code}
> The saveToSnapshot here is totally redundant as the entire H2 database is
> dumped into the dbScript field.
> Note: one major side-effect here is if anyone is trying to read these
> snapshots and utilize the data outside of Java - they'll lose the ability to
> process the data without being able to apply the DB script.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
