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https://issues.apache.org/jira/browse/PHOENIX-5082?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16729636#comment-16729636
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Lars Hofhansl edited comment on PHOENIX-5082 at 12/27/18 4:38 PM:
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8. Skipping of uncommitted rows seems also *very* slow. I upserted about 400k
rows, doing a count\(*) from another client times out after 180s (I have set
all the timeouts to 180s).
In the profiler I see that all the time is spent in
{{readCommitTimestampFromShadowCell}}, and that is spending all the time
Region.get(...) which causes a seek, which is slow with FAST_DIFF encoding.
I'll try with ROW_INDEX_V1 encoding - which I think should be the default for
Phoenix anyway.
ROW_INDEX_V1 didn't help much. Attached another profiler shot of this - just
for future reference.
Can't we just include the shadow column in the original scan and then simply
filter on it? (Rather than retrieving another column from the very same row
with a very expensive Get request)
was (Author: lhofhansl):
8. Skipping of uncommitted rows seems also *very* slow. I upserted about 400k
rows, doing a count\(*) from another client times out after 180s (I have set
all the timeouts to 180s).
In the profiler I see that all the time is spent in
{{readCommitTimestampFromShadowCell}}, and that is spending all the time
Region.get(...) which causes a seek, which is slow with FAST_DIFF encoding.
I'll try with ROW_INDEX_V1 encoding - which I think should be the default for
Phoenix anyway.
ROW_INDEX_V1 didn't help much. Attached another profiler shot of this - just
for future reference.
Can't we just include the shadow column in the original scan and then simply
filter on it? (Rather than retrieving another column from the very same row
with a very expensive Get request)
Update: It's not just skipping rows, it's scans in general.
> Observations about the Phoenix-Omid integration
> -----------------------------------------------
>
> Key: PHOENIX-5082
> URL: https://issues.apache.org/jira/browse/PHOENIX-5082
> Project: Phoenix
> Issue Type: Task
> Reporter: Lars Hofhansl
> Assignee: Yonatan Gottesman
> Priority: Major
> Attachments: CommitTS-Sample.png, Omid-profile.png, Omid-sample.png
>
>
> Filing this issue to track my observations and perhaps some fixes.
> [~ohads]
> [~jamestaylor]
> [~yonigo]
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