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Lars Hofhansl commented on HBASE-23602: --------------------------------------- When you set a TTL and KEEP_DELETED_CELLS=TTL and *MIN_VERSIONS* you get that. Now HBase will keep everything (up to VERSIONS) until the TTL expires, after that it keep MIN_VERSIONS. At least that's what I had in mind when I added MIN_VERSIONS and KEEP_DELETED_CELLS to HBase back in the day. Granted it's a bit convoluted, but pretty flexible this way. Say VERSIONS=MAX_INT, TTL=5days, KEEP_DELETED_CELLS=TTL, MIN_VERSIONS=2. Now within 5 days you have everything - all Puts, all Deletes, etc, and you can do correct point-in-time queries. After 5 days HBase retains 2 versions only. > TTL Before Which No Data is Purged > ---------------------------------- > > Key: HBASE-23602 > URL: https://issues.apache.org/jira/browse/HBASE-23602 > Project: HBase > Issue Type: New Feature > Reporter: Geoffrey Jacoby > Assignee: Geoffrey Jacoby > Priority: Major > Fix For: 3.0.0, 2.3.0, 1.6.0 > > > HBase currently offers operators a choice. They can set > KEEP_DELETED_CELLS=true and VERSIONS to max value, plus no TTL, and they will > always have a complete history of all changes (but high storage costs and > penalties to read performance). Or they can have KEEP_DELETED_CELLS=false and > VERSIONS/TTL set to some reasonable values, but that means that major > compactions can destroy the ability to do a consistent snapshot read of any > prior time. (This limits the usefulness and correctness of, for example, > Phoenix's SCN lookback feature.) > I propose having a new TTL property to give a minimum age that an expired or > deleted Cell would have to achieve before it could be purged. (I see that > HBASE-10118 already does something similar for the delete markers > themselves.) > This would allow operators to have a consistent history for some finite > amount of recent time while still purging out the "long tail" of obsolete / > deleted versions. -- This message was sent by Atlassian Jira (v8.3.4#803005)