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From "Eric Newton (JIRA)" <>
Subject [jira] [Commented] (ACCUMULO-4114) examine performance decrease with many tablets
Date Wed, 20 Jan 2016 19:36:39 GMT


Eric Newton commented on ACCUMULO-4114:

Current theory is that the metadata table is being squeezed into a smaller space, while needing
to hold more and more data.

I have attached another graph. This time I simply counted the number of MinC's and MajC's
of the metadata table that have taken place during the test run.  It certainly correlates
with lower performance.

> examine performance decrease with many tablets
> ----------------------------------------------
>                 Key: ACCUMULO-4114
>                 URL:
>             Project: Accumulo
>          Issue Type: Task
>          Components: client, tserver
>            Reporter: Eric Newton
>            Assignee: Eric Newton
>             Fix For: 1.8.0
>         Attachments: MetadataCompactionsPerTest.png, PerfWithMoreTablets.png
> While writing a performance test for ACCUMULO-4112, I noticed the performance drop for
large numbers of tablets hosted on a single server.
> Some decrease in performance is expected since the various queues and buffers are being
divided among a greater number of tablets, but a 5x decrease is unexpected.  Given other fixes
(ACCUMULO-3423, for example) I would not expect performance to drop off so dramatically.
> Investigate the performance of conditional updates going to many tablets, vs one tablet.

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