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https://issues.apache.org/jira/browse/HBASE-14995?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15061976#comment-15061976
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Anoop Sam John commented on HBASE-14995:
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bq. in HFileWriterImpl.java's append(), is the cell either NoTagsKeyValue or
TagRewriteCell
That was a good question. It made me to read the write flow again. Yes ideally
we think it will be any of these. But the fact is it wont be any of these (by
default).
By default we have MSLAB usage enabled which makes the cell to be
reconstructed (by copying the bytes to a new byte[] and create a KeyValue
object) just before adding it to CSLM in Memstore. So the optimization what we
thought wont getting applied.!! Our bad... did not think abt this before. We
need some optimization. CC [~ram_krish]
> Optimize setting tagsPresent in DefaultMemStore.java
> ----------------------------------------------------
>
> Key: HBASE-14995
> URL: https://issues.apache.org/jira/browse/HBASE-14995
> Project: HBase
> Issue Type: Improvement
> Components: regionserver
> Affects Versions: 2.0.0, 1.2.0
> Reporter: huaxiang sun
> Assignee: huaxiang sun
> Priority: Minor
> Attachments: HBASE-14995-v001.patch, HBASE-14995-v002.patch
>
>
> The current implementation calls e.getTagsLength() for each cell. Once
> tagsPresent is set, e.getTagsLength() can be avoided.
> {code}
> private boolean addToCellSet(Cell e) {
> boolean b = this.cellSet.add(e);
> // In no tags case this NoTagsKeyValue.getTagsLength() is a cheap call.
> // When we use ACL CP or Visibility CP which deals with Tags during
> // mutation, the TagRewriteCell.getTagsLength() is a cheaper call. We do
> not
> // parse the byte[] to identify the tags length.
> if(e.getTagsLength() > 0) {
> tagsPresent = true;
> }
> setOldestEditTimeToNow();
> return b;
> }
> {code}
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