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  1. Phoenix Tephra
  2. TEPHRA-134

Allow returning multiple versions in Scan

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    Details

    • Type: New Feature
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.6.3
    • Component/s: None
    • Labels:

      Description

      In support of secondary indexes, we have a need for a Scan to return multiple versions during index maintenance. This occurs when:

      • a row for an indexed table is updated which causes
        • the old index row to be deleted
        • the new index row to be added
      • a query is issued against the table which would cause the index to be used which causes the index updates to be written to HBase but not yet committed.
      • a rollback occurs

      In this case, we need to issue two point deletes: one for the new index row that was added and one for the old index row that was deleted. Ideally, we'd like to do this in a single scan, but instead we're doing two scans: one with a visibility of SNAPSHOT and one with a visibility of SNAPSHOT_EXCLUDE_CURRENT. This works but is going to impact performance.

      If we could do a single scan and get back both Puts, that would be ideal. It's somewhat related to TEPHRA-50, in that one of the Puts would represent a deletion, but we'd want to honor the filtering of inflight and invalid transactions in the scan. We could likely have our own scan and copy/paste your filter, but that's pretty ugly.

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            • Assignee:
              poorna Poorna Chandra
              Reporter:
              jamestaylor James R. Taylor
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                Updated:
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