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https://issues.apache.org/jira/browse/ACCUMULO-2175?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Josh Elser updated ACCUMULO-2175:
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Fix Version/s: (was: 1.7.0)
1.8.0
> Batch defining tablets in walog
> -------------------------------
>
> Key: ACCUMULO-2175
> URL: https://issues.apache.org/jira/browse/ACCUMULO-2175
> Project: Accumulo
> Issue Type: Improvement
> Reporter: Keith Turner
> Fix For: 1.8.0
>
>
> If a batch of mutations comes into a tablet server AND the tablet server just
> got a new walog then it will sync the walog for each tablet. Below is a
> sketch of what the tablet server currently does.
> {code:java}
> foreach(Tablet t : tabletsInMutationBatch){
> if(!tabletIsDefinedInWalog(t, currentWalog)){
> defineTablet(currentWalog, t); //syncs walog
> addWalogToMetadataTable(currentWalog, t); //syncronous metadata table
> update
> }
> }
> {code}
> Seems like doing the following would be better. Then no matter how many
> undefined tablets there are, only one walog sync would be done.
> {code:java}
> foreach(Tablet t : tabletsInMutationBatch){
> Set<Tablet> undefined = new HashSet<Tablet>();
> if(!tabletIsDefinedInWalog(t, currentWalog)){
> undefined.add(t);
> }
> }
> defineTablets(currentWalog, undefined); //syncs walog after writing all
> definitions
> addWalogToMetadataTable(currentWalog, undefined); //syncronous metadata table
> batch write
> {code}
> There is not problem when all tablets in a batch update are defined in the
> walog. In this case a batch update that contains multiple tablet will only
> sync the log once after adding all the mutations from all tablets.
> Noticed this while looking into ACCUMULO-2172
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