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https://issues.apache.org/jira/browse/PHOENIX-5494?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16974628#comment-16974628
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Lars Hofhansl commented on PHOENIX-5494:
----------------------------------------
Let's put a comment here:
{code}
@Override
public Result getCurrentRowState(Mutation m, Collection<? extends
ColumnReference> columns, boolean ignoreNewerMutations)
throws IOException {
- byte[] row = m.getRow();
+ byte[] row = m.getRow();
+ Result r;
+ if (results != null) {
+ if (m.getAttribute(BaseScannerRegionObserver.REPLAY_WRITES) == null)
{
+ r = results.get(new ImmutableBytesPtr(row));
+ if (r == null) {
+ List<Cell> kvs = new ArrayList<Cell>(1);
+ r = Result.create(kvs);
+ }
+ return r;
+ }
+ }
{code}
Explaining what's going to pointed back to the IndexRegionObserver where we
pre-fill the batch.
> 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: 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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