[jira] [Updated] (CASSANDRA-19652) ShallowInfoRetriever: cache offsets to void resetting of RandomAccessReader buffer
[ https://issues.apache.org/jira/browse/CASSANDRA-19652?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Brandon Williams updated CASSANDRA-19652: - Change Category: Performance Complexity: Normal Status: Open (was: Triage Needed) > ShallowInfoRetriever: cache offsets to void resetting of RandomAccessReader > buffer > -- > > Key: CASSANDRA-19652 > URL: https://issues.apache.org/jira/browse/CASSANDRA-19652 > Project: Cassandra > Issue Type: Improvement > Components: Local/SSTable >Reporter: Dmitry Konstantinov >Assignee: Dmitry Konstantinov >Priority: Normal > Fix For: 5.x > > > Currently in > org.apache.cassandra.io.sstable.format.big.RowIndexEntry.ShallowInfoRetriever#fetchIndex > we do 2 seek/read operations: 1st is to find the offset for IndexInfo and > the 2nd to read it. These are two quite distant regions of the file and for > standard disk access mode we do not use a benefit from a buffer in > RandomAccessReader due to jumping between the regions and reseting this > buffer again and again. A possible improvement here can be to read and cache > N first offsets (to limit the amount of memory to use) on the first read and > do later only sequential reads of IndexInfo data. By caching of less than 1Kb > we can reduce the number of syscalls even more, in my case: from few hundred > to less than 10. -- This message was sent by Atlassian Jira (v8.20.10#820010) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Updated] (CASSANDRA-19652) ShallowInfoRetriever: cache offsets to void resetting of RandomAccessReader buffer
[ https://issues.apache.org/jira/browse/CASSANDRA-19652?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Dmitry Konstantinov updated CASSANDRA-19652: Fix Version/s: 5.x > ShallowInfoRetriever: cache offsets to void resetting of RandomAccessReader > buffer > -- > > Key: CASSANDRA-19652 > URL: https://issues.apache.org/jira/browse/CASSANDRA-19652 > Project: Cassandra > Issue Type: Improvement > Components: Local/SSTable >Reporter: Dmitry Konstantinov >Priority: Normal > Fix For: 5.x > > > Currently in > org.apache.cassandra.io.sstable.format.big.RowIndexEntry.ShallowInfoRetriever#fetchIndex > we do 2 seek/read operations: 1st is to find the offset for IndexInfo and > the 2nd to read it. These are two quite distant regions of the file and for > standard disk access mode we do not use a benefit from a buffer in > RandomAccessReader due to jumping between the regions and reseting this > buffer again and again. A possible improvement here can be to read and cache > N first offsets (to limit the amount of memory to use) on the first read and > do later only sequential reads of IndexInfo data. By caching of less than 1Kb > we can reduce the number of syscalls even more, in my case: from few hundred > to less than 10. -- This message was sent by Atlassian Jira (v8.20.10#820010) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
