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ASF GitHub Bot updated ACCUMULO-3510: ------------------------------------- Labels: pull-request-available (was: ) > Create mechanism to support priority based scheduling of read ahead tasks. > --------------------------------------------------------------------------- > > Key: ACCUMULO-3510 > URL: https://issues.apache.org/jira/browse/ACCUMULO-3510 > Project: Accumulo > Issue Type: Improvement > Components: tserver > Affects Versions: 1.6.0 > Reporter: marco polo > Assignee: marco polo > Priority: Minor > Labels: pull-request-available > Fix For: 2.0.0 > > > I have many cases where ScanSessions will consume resources that I otherwise > want shorter running scans to utilize. In some cases, a scan may continue for > hours, while a short running scan may come in and execute quickly. As a > result, I want to be able to adjust the priority of these scan sessions. > I have a patch which is forthcoming, that breaks Session out of TabletServer > and replaces the queue in the readAheadThreadPool with a priority pool. The > comparator I have created as a proof of concept, which can be adjustable, > reduces the priority of the oldest scan. Using an aging technique, we > guarantee execute of these older running scans based upon the previous run > time. As a result, we give preference to newer scans. If they execute > quickly, older scans will have an inherent rise in priority. If they also > take a while, their priority will be reduced and incoming scans will yet > again be given a greater priority with the intent (and/or hope ) their > execution will be faster. > Priority should be configurable based on the desired Session Comparator. -- This message was sent by Atlassian JIRA (v7.6.3#76005)