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https://issues.apache.org/jira/browse/HBASE-9000?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13807651#comment-13807651
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Liang Xie commented on HBASE-9000:
----------------------------------
Just my understanding: our current impl in trunk or the old 0.89-fb impl seems
not optimized against all cases, one type of case probably is friendly with
current logarithmic seek imple(tailSet), e.g. lots of kv needs to be skipped;
another type of case is friendly with linear reseek, e.g. the target kv is
near with the previous position, like 0.89-fb's old impl like :
{code}
public boolean reseek(KeyValue key) {
while (kvsetNextRow != null &&
comparator.compare(kvsetNextRow, key) < 0) {
kvsetNextRow = getNext(kvsetIt);
}
...
{code}
to me, it's reasonable to have a setting value to : let the cheaper linear
reseek go first, then fallback to more expensive seek() ops after reaching a
config value.
> Linear reseek in Memstore
> -------------------------
>
> Key: HBASE-9000
> URL: https://issues.apache.org/jira/browse/HBASE-9000
> Project: HBase
> Issue Type: Improvement
> Affects Versions: 0.89-fb
> Reporter: Shane Hogan
> Priority: Minor
> Fix For: 0.89-fb
>
>
> This is to address the linear reseek in MemStoreScanner. Currently reseek
> iterates over the kvset and the snapshot linearly by just calling next
> repeatedly. The new solution is to do this linear seek up to a configurable
> maximum amount of times then if the seek is not yet complete fall back to
> logarithmic seek.
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