Re: Getting rid of "delete forward" in HBase 0.92+, please weigh in
Hi, Right now deletes work by inserting a special delete marker, aka "tombstone" complete with timestamp. The issue happens when you create a delete with a timestamp in the future, it masks deletes that have not happened yet. This is what I mean by "delete forward" - you are deleting data that hasn't been inserted yet! From those used to systems like MySQL, this is very confusing, hence this proposal. -ryan On Sat, Jan 8, 2011 at 1:29 AM, Henning Blohm wrote: > +1 from here as well > > Please let delete work as if it was just a special marker value of a > column (i.e. with a time stamp and all). > > On Fri, 2011-01-07 at 19:24 -0800, M. C. Srivas wrote: > >> +1 >> >> Just a clarification : by delete-forward, do you mean that a delete of a >> non-existent key causes a future insert of the key to get deleted? >> >> >> On Fri, Jan 7, 2011 at 4:23 PM, Ryan Rawson wrote: >> >> > Hi all, >> > >> > We are thinking of getting rid of the "delete forward" misfeature in >> > HBase. The one way we'd implement it would permanently remove this >> > "feature", and prevent it from being put back in ever. >> > >> > What is a delete forward you ask? This is where you do a delete, but >> > because deletes are really just inserting 'tombstones', it applies to >> > future Puts. This can be immensely frustrating because puts appear to >> > do nothing. These rogue deletes get pruned out when the table is major >> > compacted, so it isn't forever. >> > >> > Because of the transient nature of these delete forwards, we suspect, >> > but do not know, if anyone is depending on this behaviour. If you use >> > this behaviour, please chime in so we can get a sense of what people >> > need! >> > >> > Thanks! >> > -ryan >> > >
Re: Getting rid of "delete forward" in HBase 0.92+, please weigh in
+1 from here as well Please let delete work as if it was just a special marker value of a column (i.e. with a time stamp and all). On Fri, 2011-01-07 at 19:24 -0800, M. C. Srivas wrote: > +1 > > Just a clarification : by delete-forward, do you mean that a delete of a > non-existent key causes a future insert of the key to get deleted? > > > On Fri, Jan 7, 2011 at 4:23 PM, Ryan Rawson wrote: > > > Hi all, > > > > We are thinking of getting rid of the "delete forward" misfeature in > > HBase. The one way we'd implement it would permanently remove this > > "feature", and prevent it from being put back in ever. > > > > What is a delete forward you ask? This is where you do a delete, but > > because deletes are really just inserting 'tombstones', it applies to > > future Puts. This can be immensely frustrating because puts appear to > > do nothing. These rogue deletes get pruned out when the table is major > > compacted, so it isn't forever. > > > > Because of the transient nature of these delete forwards, we suspect, > > but do not know, if anyone is depending on this behaviour. If you use > > this behaviour, please chime in so we can get a sense of what people > > need! > > > > Thanks! > > -ryan > >
Re: Getting rid of "delete forward" in HBase 0.92+, please weigh in
Yes that's it exactly! On Jan 7, 2011 7:24 PM, "M. C. Srivas" wrote: > +1 > > Just a clarification : by delete-forward, do you mean that a delete of a > non-existent key causes a future insert of the key to get deleted? > > > On Fri, Jan 7, 2011 at 4:23 PM, Ryan Rawson wrote: > >> Hi all, >> >> We are thinking of getting rid of the "delete forward" misfeature in >> HBase. The one way we'd implement it would permanently remove this >> "feature", and prevent it from being put back in ever. >> >> What is a delete forward you ask? This is where you do a delete, but >> because deletes are really just inserting 'tombstones', it applies to >> future Puts. This can be immensely frustrating because puts appear to >> do nothing. These rogue deletes get pruned out when the table is major >> compacted, so it isn't forever. >> >> Because of the transient nature of these delete forwards, we suspect, >> but do not know, if anyone is depending on this behaviour. If you use >> this behaviour, please chime in so we can get a sense of what people >> need! >> >> Thanks! >> -ryan >>
Re: Getting rid of "delete forward" in HBase 0.92+, please weigh in
+1 Just a clarification : by delete-forward, do you mean that a delete of a non-existent key causes a future insert of the key to get deleted? On Fri, Jan 7, 2011 at 4:23 PM, Ryan Rawson wrote: > Hi all, > > We are thinking of getting rid of the "delete forward" misfeature in > HBase. The one way we'd implement it would permanently remove this > "feature", and prevent it from being put back in ever. > > What is a delete forward you ask? This is where you do a delete, but > because deletes are really just inserting 'tombstones', it applies to > future Puts. This can be immensely frustrating because puts appear to > do nothing. These rogue deletes get pruned out when the table is major > compacted, so it isn't forever. > > Because of the transient nature of these delete forwards, we suspect, > but do not know, if anyone is depending on this behaviour. If you use > this behaviour, please chime in so we can get a sense of what people > need! > > Thanks! > -ryan >
Getting rid of "delete forward" in HBase 0.92+, please weigh in
Hi all, We are thinking of getting rid of the "delete forward" misfeature in HBase. The one way we'd implement it would permanently remove this "feature", and prevent it from being put back in ever. What is a delete forward you ask? This is where you do a delete, but because deletes are really just inserting 'tombstones', it applies to future Puts. This can be immensely frustrating because puts appear to do nothing. These rogue deletes get pruned out when the table is major compacted, so it isn't forever. Because of the transient nature of these delete forwards, we suspect, but do not know, if anyone is depending on this behaviour. If you use this behaviour, please chime in so we can get a sense of what people need! Thanks! -ryan