[ https://issues.apache.org/jira/browse/CASSANDRA-17071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17452929#comment-17452929 ]
Alex Petrov commented on CASSANDRA-17071: ----------------------------------------- +1. Extra credit for an awesome fuzz test! > Relax schema synchronization when opening a keyspace > ---------------------------------------------------- > > Key: CASSANDRA-17071 > URL: https://issues.apache.org/jira/browse/CASSANDRA-17071 > Project: Cassandra > Issue Type: Improvement > Components: Cluster/Schema > Reporter: Jacek Lewandowski > Assignee: Jacek Lewandowski > Priority: Normal > Time Spent: 1h 40m > Remaining Estimate: 0h > > Extracted this as a separate ticket per discussion on CASSANDRA-17044 > In short, there are two purposes of this change: > # Move the code around to the more appropriate places (for example, CFS > specific code for dropping table was moved from SM class to CFS class) > # Relax the synchronization when adding/removing keyspace instances in SM - > instead of synchronizing the whole collection of keyspace instances, we only > synchronize the related item (the original idea authored by [~blambov]). > The current implementation works because a certain order of opening keyspaces > is assumed. If a keyspace is already initialized, it is just returned without > sync and sync is done only to initialize the keyspace. When synchronization > is extended to the whole method, the system finds itself in a deadlock. This > means that some keyspace is tried to be opened during initiazation. Currently > it works fine because the keyspace which is not initialized yet is never > tried to be opened asynchronously while initializing some other keyspace in a > different thread. Hence the conclusion about fragility of the current > solution. -- This message was sent by Atlassian Jira (v8.20.1#820001) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org