tolbertam opened a new pull request, #4164: URL: https://github.com/apache/cassandra/pull/4164
Updates SystemKeyspace.writePreparedStatement to accept a timestamp associated with the Prepared creation time. Using this timestamp will ensure that an INSERT into system.prepared_statements will always precede the timestamp for the same Prepared in SystemKeyspace.removePreparedStatement. This is needed because Caffeine 2.9.2 may evict an entry as soon as it is inserted if the maximum weight of the cache is exceeded causing the DELETE to be executed before the INSERT. Additionally, any clusters currently experiencing a leaky system.prepared_statements table from this bug may struggle to bounce into a version with this fix as SystemKeyspace.loadPreparedPreparedStatements currently does not paginate the query to system.prepared_statements, causing heap OOMs. To fix this this patch adds pagination at 5000 rows and aborts loading once the cache size is loaded. This should allow nodes to come up and delete older prepared statements that may no longer be used as the cache fills up (which should happen immediately). This patch does not address the issue of Caffeine immediately evicting a prepared statement, however it will prevent the system.prepared_statements table from growing unbounded. For most users this should be adequate, as the cache should only be filled when there are erroneously many unique prepared statements. In such a case we can expect that clients will constantly prepare statements regardless of whether or not the cache is evicting statements. patch by Andy Tolbert; reviewed by Berenguer Blasi and Caleb Rackliffe for CASSANDRA-19703 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For additional commands, e-mail: pr-h...@cassandra.apache.org
