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Vladimir Rodionov edited comment on HBASE-17339 at 12/19/16 8:09 PM: --------------------------------------------------------------------- This won't work in a general case. You may have KV in Memory and in store files (different versions). HBase does not give you a guarantee, that memory version is what you ask for (unless you specify exact version). This can be used only as a hint: If KV is memory give it to me, or MESTORE_FIRST. was (Author: vrodionov): I think this won't work in general case. You may have KV in Memory and in store files (different versions). HBase does not give you a guarantee, that memory version is what you ask for (unless you specify exact version). This can be used only as a hint: If KV is memory give it to me, or MESTORE_FIRST. > Scan-Memory-First Optimization > ------------------------------ > > Key: HBASE-17339 > URL: https://issues.apache.org/jira/browse/HBASE-17339 > Project: HBase > Issue Type: Improvement > Reporter: Eshcar Hillel > Attachments: HBASE-17339-V01.patch > > > The current implementation of a get operation (to retrieve values for a > specific key) scans through all relevant stores of the region; for each store > both memory components (memstores segments) and disk components (hfiles) are > scanned in parallel. > We suggest to apply an optimization that speculatively scans memory-only > components first and only if the result is incomplete scans both memory and > disk. -- This message was sent by Atlassian JIRA (v6.3.4#6332)