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  1. Couchbase Server
  2. MB-32486

plasma does not support time series workloads

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Details

    • Bug
    • Status: Closed
    • Major
    • Resolution: Fixed
    • 6.5.0
    • 7.1.0
    • storage-engine
    • Untriaged
    • No
    • Storage-Sprint-Feb-08-2019, Storage-Sprint-Mar-15-2019

    Description

      Plasma Index is a skip list with pages at the lowest level.

      If a time series workload is used on plasma, where new keys only get appended to the tail of the skip list while documents from the start of the skip list just expire away, that puts a lot of load on the mvcc purger which is unable to keep up.

      This causes the purge ratio to shoot up and data_size to explode when customers use expiry or TTL on the kv documents.

      Current workarounds  recommended: 

      The command to reduce the number of page deltas are as follows..

       

      curl node.ip.address:9102/settings -u Administrator:password -X POST -d "{\"indexer.plasma.mainIndex.maxNumPageDeltas\":30}"
       
      curl node.ip.address:9102/settings -u Administrator:password -X POST -d "{\"indexer.plasma.backIndex.maxNumPageDeltas\":30}"

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          Activity

            Add additional logic to trigger compaction if > 50% of keys in the page is deleted.

            keshav Keshav Murthy added a comment - Add additional logic to trigger compaction if > 50% of keys in the page is deleted.
            jliang John Liang added a comment -

            close as a dup of MB-40855

            jliang John Liang added a comment - close as a dup of MB-40855

            People

              sanjit.chauhan Sanjit Chauhan (Inactive)
              sundar Sundar Sridharan (Inactive)
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              Dates

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                Updated:
                Resolved:

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