[jira] [Commented] (ACCUMULO-3508) Zoocache utilizes course grained locking causing unnecessary synchronization in many tserver ops
[ https://issues.apache.org/jira/browse/ACCUMULO-3508?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15060689#comment-15060689 ] Christopher Tubbs commented on ACCUMULO-3508: - Should this be backported to 1.6.5 and/or 1.7.1, since it was originally reported against 1.6.0? > Zoocache utilizes course grained locking causing unnecessary synchronization > in many tserver ops > > > Key: ACCUMULO-3508 > URL: https://issues.apache.org/jira/browse/ACCUMULO-3508 > Project: Accumulo > Issue Type: Sub-task > Components: fate >Affects Versions: 1.6.0 >Reporter: marco polo >Assignee: marco polo >Priority: Minor > Fix For: 1.8.0 > > Time Spent: 10m > Remaining Estimate: 0h > > Through jstacking I have observed busy tablet server threads waiting for the > Zoocache to be updated or even read. Profiling via yourkit indicates > potential deadlocks when threads wait for a long period of time ( in my case > my waits were 10+s ) when many scans were running against my instance. > My patch, which is forthcoming, removes synchronization and utilizes a > reentrant read/write lock (RERWL) to synchronize the maps. My initial design > utilized concurrent hash maps, but the design of existence becomes simpler > and changes fewer by using the RERWL. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (ACCUMULO-3508) Zoocache utilizes course grained locking causing unnecessary synchronization in many tserver ops
[ https://issues.apache.org/jira/browse/ACCUMULO-3508?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14561766#comment-14561766 ] Christopher Tubbs commented on ACCUMULO-3508: - What's the status of this? Is a patch available? [~phrocker], are you still working on this? Zoocache utilizes course grained locking causing unnecessary synchronization in many tserver ops Key: ACCUMULO-3508 URL: https://issues.apache.org/jira/browse/ACCUMULO-3508 Project: Accumulo Issue Type: Sub-task Components: fate Affects Versions: 1.6.0 Reporter: marco polo Assignee: marco polo Priority: Minor Fix For: 1.6.3, 1.8.0, 1.7.1 Through jstacking I have observed busy tablet server threads waiting for the Zoocache to be updated or even read. Profiling via yourkit indicates potential deadlocks when threads wait for a long period of time ( in my case my waits were 10+s ) when many scans were running against my instance. My patch, which is forthcoming, removes synchronization and utilizes a reentrant read/write lock (RERWL) to synchronize the maps. My initial design utilized concurrent hash maps, but the design of existence becomes simpler and changes fewer by using the RERWL. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (ACCUMULO-3508) Zoocache utilizes course grained locking causing unnecessary synchronization in many tserver ops
[ https://issues.apache.org/jira/browse/ACCUMULO-3508?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14287874#comment-14287874 ] Josh Elser commented on ACCUMULO-3508: -- [~phrocker], I've added you as a contributor. Look forward to a patch -- thanks! Zoocache utilizes course grained locking causing unnecessary synchronization in many tserver ops Key: ACCUMULO-3508 URL: https://issues.apache.org/jira/browse/ACCUMULO-3508 Project: Accumulo Issue Type: Sub-task Components: fate Affects Versions: 1.6.0 Reporter: marco polo Priority: Minor Fix For: 1.6.3 Through jstacking I have observed busy tablet server threads waiting for the Zoocache to be updated or even read. Profiling via yourkit indicates potential deadlocks when threads wait for a long period of time ( in my case my waits were 10+s ) when many scans were running against my instance. My patch, which is forthcoming, removes synchronization and utilizes a reentrant read/write lock (RERWL) to synchronize the maps. My initial design utilized concurrent hash maps, but the design of existence becomes simpler and changes fewer by using the RERWL. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
