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https://issues.apache.org/jira/browse/PHOENIX-5494?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16974811#comment-16974811
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chenglei commented on PHOENIX-5494:
-----------------------------------
[~larsh], sorry for later response. I have already made a patch using
{{SkipScanFilter}} in my production environment(which is hbase1.4.10) yesterday
to solve this problem.
After reading [~kozdemir] 's patch, there are some suggestions I think we can
do better:
1. Scan.startRow and Scan.endRow should be set to improve the scanner
performance in additional to just using the Filter:
{code:java}
s.setFilter(new MultiRowRangeFilter(ranges));
s.setTimeRange(0, ts);
Region region = this.env.getRegion();
try (RegionScanner scanner = region.getScanner(s)) {
{code}
2. In additional to normal updates, we can also using the this optimization
when replaying write.
3. {{LocalTable}} is global region-scope, so if we add a member variable
{{LocalTable.results }} to make it stateful, there may be many concurrent
issues. I think we would better create a new class(for example
CachedLocalTable) to hold the results we pre-scannered and make the object as a
local variable and passed it to downstream
{{IndexBuilder.getIndexUpdate(Mutation, IndexMetaData, LocalHBaseState)}} local
method parameter to
> Batched, mutable Index updates are unnecessarily run one-by-one
> ---------------------------------------------------------------
>
> Key: PHOENIX-5494
> URL: https://issues.apache.org/jira/browse/PHOENIX-5494
> Project: Phoenix
> Issue Type: Improvement
> Reporter: Lars Hofhansl
> Assignee: Kadir OZDEMIR
> Priority: Major
> Labels: performance
> Attachments: 5494-4.x-HBase-1.5.txt, PHOENIX-5494.master.001.patch,
> PHOENIX-5494.master.002.patch, PHOENIX-5494.master.003.patch,
> Screenshot_20191110_160243.png, Screenshot_20191110_160351.png,
> Screenshot_20191110_161453.png
>
> Time Spent: 1h 20m
> Remaining Estimate: 0h
>
> I just noticed that index updates on mutable tables retrieve their deletes
> (to invalidate the old index entry) one-by-one.
> For batches, this can be *the* major time spent during an index update. The
> cost is mostly incured by the repeated setup (and seeking) of the new region
> scanner (for each row).
> We can instead do a skip scan and get all updates in a single scan per region.
> (Logically that is simple, but it will require some refactoring)
> I won't be getting to this, but recording it here in case someone feels
> inclined.
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