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https://issues.apache.org/jira/browse/PHOENIX-3739?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15928754#comment-15928754
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Lars Hofhansl commented on PHOENIX-3739:
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Or at least turn them into SMALL scans (if they aren't already - can't check
easily this second)
> Turn pure point lookups into HBase Gets
> ---------------------------------------
>
> Key: PHOENIX-3739
> URL: https://issues.apache.org/jira/browse/PHOENIX-3739
> Project: Phoenix
> Issue Type: Improvement
> Reporter: James Taylor
> Priority: Minor
>
> HBase provides a means of isolating resources based on read/write and further
> based on the operation (Scan versus Get). To leverage this, Phoenix could
> turn a pure point lookup scan into a series of Gets (or a MultiGet when
> that's available).
> Best to look at an example query to outline some potential issues:
> {code}
> SELECT * FROM MY.TABLE
> WHERE ID IN ('001','123','002', '456') AND COL1 > 10
> {code}
> Phoenix turns this into a scan per region pushing the IDs through our skip
> scan filter which does seeks to each row. The {{COL1 > 10}} turns into filter
> as well which is anded with the skip scan filter.
> Some potential issues to overcome are:
> - Extra RPC calls. We're had use cases in which 250K keys are pushed through
> the skip scan filter. We wouldn't want to turn this into 250K RPCs. Perhaps
> there's some kind of multi/batch operation that could be leveraged for
> currently supported HBase versions since it looks like MultiGet is targeted
> for HBase 2.0.
> - Extra payload per Get call. With the Scan approach, the extra filter for
> {{COL1 > 10}} is passed once. With this approach, we'd need to pass this for
> every Get operation.
> - Code consistency. It's nice to have a single code path in Phoenix that's
> consistent across all queries. Phoenix knows when a scan becomes a pure point
> lookup, though, so this can be overcome - it just adds a little complexity.
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