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https://issues.apache.org/jira/browse/HBASE-10247?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14008283#comment-14008283
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Lars Hofhansl commented on HBASE-10247:
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Cool... So how do we make progress here? Should I make a patch?
Looking at HBASE-9905, good policies might be:
* seqid
* server_ts
* client_monotonic
* mixed
Might also be good to indicate when the TS field is used for something that is
not wall clock time (so that we do not attempt to use TTL, etc).
I could start with the config framework (that is simple anyway), and adding
"server_ts", "mixed", and "client_monotonic". "server_ts" would the default for
new tables. We can then add seqid as that gets ready.
> Client promises about timestamps
> --------------------------------
>
> Key: HBASE-10247
> URL: https://issues.apache.org/jira/browse/HBASE-10247
> Project: HBase
> Issue Type: Brainstorming
> Reporter: Lars Hofhansl
> Priority: Minor
>
> This is to start a discussion about timestamp promises declared per table of
> CF.
> For example if a client promises only monotonically increasing timestamps (or
> no custom set timestamps) and VERSIONS=1, we can aggressively and easily
> remove old versions of the same row/fam/col from the memstore before we
> flush, just by supplying a comparator that ignores the timestamp (i.e. two KV
> just differing by TS would be considered equal).
> That would increase the performance of counters significantly.
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