Yes, TTL deletions are done only during compactions. They aren't "Deleted" in the sense of what a Delete insert signifies, but are rather eliminated in the write process when new storefiles are written out - if the value being written to the compacted store has already expired.
On Tue, Aug 14, 2012 at 8:40 PM, yonghu <yongyong...@gmail.com> wrote: > Hi Hars, > > Thanks for your reply. If I understand you right, it means the ttl > deletion will not reflect in log. > > On Tue, Aug 14, 2012 at 3:24 PM, Harsh J <ha...@cloudera.com> wrote: >> Hi Yonghu, >> >> A timestamp is stored along with each insert. The ttl is maintained at >> the region-store level. Hence, when the log replays, all entries with >> expired TTLs are automatically omitted. >> >> Also, TTL deletions happen during compactions, and hence do not >> carry/need Delete events. When scanning a store file, TTL-expired >> entries are automatically skipped away. >> >> On Tue, Aug 14, 2012 at 3:34 PM, yonghu <yongyong...@gmail.com> wrote: >>> My hbase version is 0.92. I tried something as follows: >>> 1.Created a table 'test' with 'course' in which ttl=5. >>> 2. inserted one row into the table. 5 seconds later, the row was deleted. >>> Later when I checked the log infor of 'test' table, I only found the >>> inserted information but not deleted information. >>> >>> Can anyone tell me which information is written into hlog when data is >>> deleted by ttl or in this situation, no information is written into >>> the hlog. If there is no information of deletion in the log, how can >>> we guarantee the data recovered by log are correct? >>> >>> Thanks! >>> >>> Yong >> >> >> >> -- >> Harsh J -- Harsh J
