[
https://issues.apache.org/jira/browse/HBASE-17339?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15780100#comment-15780100
]
Phil Yang commented on HBASE-17339:
-----------------------------------
This optimization indeed speeds up some cases of Get operation. However, a
server-level configuration is dangerous because we may not make sure users
never set a backward timestamp in all tables/families. I think we can make it
a CF-level conf in HColumnDescriptor and ban user-setting TS in these CFs? And
we need make sure all TSs generate by server will never go backward, or at
least larger than max TS of flushed cells
> Scan-Memory-First Optimization for Get Operation
> ------------------------------------------------
>
> 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)
