[jira] [Commented] (CASSANDRA-8459) autocompaction on reads can prevent memtable space reclaimation
[ https://issues.apache.org/jira/browse/CASSANDRA-8459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14242511#comment-14242511 ] Philo Yang commented on CASSANDRA-8459: --- Hi, [~benedict], there is no node in my cluster that is unresponsive to dump the heap. But there are some hprof files dumped by +HeapDumpOnOutOfMemoryError automatically, are they helpful to you? If so I'll upload one of them. autocompaction on reads can prevent memtable space reclaimation - Key: CASSANDRA-8459 URL: https://issues.apache.org/jira/browse/CASSANDRA-8459 Project: Cassandra Issue Type: Bug Components: Core Reporter: Benedict Assignee: Benedict Fix For: 2.1.3 Attachments: 8459.txt Memtable memory reclamation is dependent on reads always making progress, however on the collectTimeOrderedData critical path it is possible for the read to perform a _write_ inline, and for this write to block waiting for memtable space to be reclaimed. However the reclaimation is blocked waiting for this read to complete. There are a number of solutions to this, but the simplest is to make the defragmentation happen asynchronously, so the read terminates normally. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-8459) autocompaction on reads can prevent memtable space reclaimation
[ https://issues.apache.org/jira/browse/CASSANDRA-8459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14242513#comment-14242513 ] Benedict commented on CASSANDRA-8459: - No need, already sussed the problem and attached the fix autocompaction on reads can prevent memtable space reclaimation - Key: CASSANDRA-8459 URL: https://issues.apache.org/jira/browse/CASSANDRA-8459 Project: Cassandra Issue Type: Bug Components: Core Reporter: Benedict Assignee: Benedict Fix For: 2.1.3 Attachments: 8459.txt Memtable memory reclamation is dependent on reads always making progress, however on the collectTimeOrderedData critical path it is possible for the read to perform a _write_ inline, and for this write to block waiting for memtable space to be reclaimed. However the reclaimation is blocked waiting for this read to complete. There are a number of solutions to this, but the simplest is to make the defragmentation happen asynchronously, so the read terminates normally. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-8459) autocompaction on reads can prevent memtable space reclaimation
[ https://issues.apache.org/jira/browse/CASSANDRA-8459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14242523#comment-14242523 ] Philo Yang commented on CASSANDRA-8459: --- Ok, Thanks! autocompaction on reads can prevent memtable space reclaimation - Key: CASSANDRA-8459 URL: https://issues.apache.org/jira/browse/CASSANDRA-8459 Project: Cassandra Issue Type: Bug Components: Core Reporter: Benedict Assignee: Benedict Fix For: 2.1.3 Attachments: 8459.txt Memtable memory reclamation is dependent on reads always making progress, however on the collectTimeOrderedData critical path it is possible for the read to perform a _write_ inline, and for this write to block waiting for memtable space to be reclaimed. However the reclaimation is blocked waiting for this read to complete. There are a number of solutions to this, but the simplest is to make the defragmentation happen asynchronously, so the read terminates normally. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-8459) autocompaction on reads can prevent memtable space reclaimation
[ https://issues.apache.org/jira/browse/CASSANDRA-8459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14242734#comment-14242734 ] Jonathan Ellis commented on CASSANDRA-8459: --- +1 Do we also need this in 2.0? autocompaction on reads can prevent memtable space reclaimation - Key: CASSANDRA-8459 URL: https://issues.apache.org/jira/browse/CASSANDRA-8459 Project: Cassandra Issue Type: Bug Components: Core Reporter: Benedict Assignee: Benedict Fix For: 2.1.3 Attachments: 8459.txt Memtable memory reclamation is dependent on reads always making progress, however on the collectTimeOrderedData critical path it is possible for the read to perform a _write_ inline, and for this write to block waiting for memtable space to be reclaimed. However the reclaimation is blocked waiting for this read to complete. There are a number of solutions to this, but the simplest is to make the defragmentation happen asynchronously, so the read terminates normally. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-8459) autocompaction on reads can prevent memtable space reclaimation
[ https://issues.apache.org/jira/browse/CASSANDRA-8459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14242738#comment-14242738 ] Benedict commented on CASSANDRA-8459: - It's probably not a *bad idea* for 2.0 as it stops a read touching the write path, but it isn't necessary for correctness. autocompaction on reads can prevent memtable space reclaimation - Key: CASSANDRA-8459 URL: https://issues.apache.org/jira/browse/CASSANDRA-8459 Project: Cassandra Issue Type: Bug Components: Core Reporter: Benedict Assignee: Benedict Fix For: 2.1.3 Attachments: 8459.txt Memtable memory reclamation is dependent on reads always making progress, however on the collectTimeOrderedData critical path it is possible for the read to perform a _write_ inline, and for this write to block waiting for memtable space to be reclaimed. However the reclaimation is blocked waiting for this read to complete. There are a number of solutions to this, but the simplest is to make the defragmentation happen asynchronously, so the read terminates normally. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-8459) autocompaction on reads can prevent memtable space reclaimation
[ https://issues.apache.org/jira/browse/CASSANDRA-8459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14242747#comment-14242747 ] Jonathan Ellis commented on CASSANDRA-8459: --- Let's leave 2.0 alone then. autocompaction on reads can prevent memtable space reclaimation - Key: CASSANDRA-8459 URL: https://issues.apache.org/jira/browse/CASSANDRA-8459 Project: Cassandra Issue Type: Bug Components: Core Reporter: Benedict Assignee: Benedict Fix For: 2.1.3 Attachments: 8459.txt Memtable memory reclamation is dependent on reads always making progress, however on the collectTimeOrderedData critical path it is possible for the read to perform a _write_ inline, and for this write to block waiting for memtable space to be reclaimed. However the reclaimation is blocked waiting for this read to complete. There are a number of solutions to this, but the simplest is to make the defragmentation happen asynchronously, so the read terminates normally. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
