Thanks, Ted & Jonathan. :) regards macf
On Fri, Jan 21, 2011 at 12:36 AM, Jonathan Gray <[email protected]> wrote: > HBase (and BigTable) use delete markers (or tombstones). As you say, once > written, all data is immutable. > > These markers look very similar to normal Put operations but the HBase > server logic processes them in a special way and when we see delete markers > we will appropriate mask (not return or make visible) data which has been > deleted. > > See the Delete class for the specific delete APIs supported. > > As Ted says, during compactions, this deleted data (masked by the delete > markers) will be permanently deleted and not included in the new compacted > file. > > Check out the BigTable paper for more information. > > JG > > > -----Original Message----- > > From: Ted Yu [mailto:[email protected]] > > Sent: Thursday, January 20, 2011 8:25 AM > > To: [email protected] > > Subject: Re: Question about HBase Delete > > > > The actual deletion happens after compaction. > > > > FYI > > > > On Thu, Jan 20, 2011 at 8:01 AM, mac fang <[email protected]> wrote: > > > > > Hi, guys, > > > > > > I read the HBase code and found the delete interface only delete the > > > keyValue in the MemoryStore, but NOT really remove the keyValue in the > > > SequenceFile, only invoke the > > > > > > this.writer.append(logKey, logEdit); > > > > > > will it remove the index in the SequenceFile. And I saw the BigTable > > > design and seems it looks like a immutable system which you even can > > > NOT delete a file. How the delete/update can be achieved in HBase > > > system? Any hints are welcome! > > > > > > regards > > > macf > > > >
