This is an old issue with sstable2json https://issues.apache.org/jira/browse/CASSANDRA-4054
Internally the tomstone is associated with the o.a.c.db.AbstractColumnContainer see o.a.c.db.RowMutation.delete() to see how a row level delete works. Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 4/06/2012, at 9:58 PM, Felipe Schmidt wrote: > I was taking a look at tombstones stored at SSTable and I noticed that if I > perform a key deletion, the tombstone doesn’t have any timestamp, he has this > appearance: > “key”:[ ] > In all the other deletions granularities the tombstone have a > timestamp.Without this information seems to be not possible to solve > conflicts when a insertion for the same key is done after this deletion. If > it happens, I think Cassandra will always delete this new information because > of this tombstone. > I’m using a single node configuration and maybe it change how does tombstones > looks like. > > Thanks in advance. > > Regards, > Felipe Mathias Schmidt > (Computer Science UFRGS, RS, Brazil) > > > > > > 2012/5/31 aaron morton <aa...@thelastpickle.com> >> -Is there any other way to stract the contect of SSTable, writing a >> java program for example instead of using sstable2json? > Look at the code in sstale2json and copy it :) > >> -I tried to get tombstons using the thrift API, but seems to be not >> possible, is it right? When I try, the program throws an exception. > No. > Tombstones are not returned from API (See ColumnFamilyStore.getColumnFamily() > ). > You can see them if you use sstable2json. > > Cheers > > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 30/05/2012, at 9:53 PM, Felipe Schmidt wrote: > >> I have further questions: >> -Is there any other way to stract the contect of SSTable, writing a >> java program for example instead of using sstable2json? >> -I tried to get tombstons using the thrift API, but seems to be not >> possible, is it right? When I try, the program throws an exception. >> >> thanks in advance >> >> Regards, >> Felipe Mathias Schmidt >> (Computer Science UFRGS, RS, Brazil) >> >> >> >> >> 2012/5/24 aaron morton <aa...@thelastpickle.com>: >>> Ok... it's really strange to me that Cassandra doesn't support data >>> versioning cause all of other key-value databases support it (at least >>> those who I know). >>> >>> You can design it into your data model if you need it. >>> >>> >>> I have one remaining question: >>> -in the case that I have more than 1 SSTable in the disk for the same >>> column but with different data versions, is it possible to make a >>> >>> query to get the old version instead of the newest one? >>> >>> No. >>> There is only ever 1 value for a column. >>> The "older" copies of the column in the SSTables are artefacts of immutable >>> on disk structures. >>> If you want to see what's inside an SSTable use bin/sstable2json >>> >>> Cheers >>> >>> ----------------- >>> Aaron Morton >>> Freelance Developer >>> @aaronmorton >>> http://www.thelastpickle.com >>> >>> On 24/05/2012, at 9:42 PM, Felipe Schmidt wrote: >>> >>> Ok... it's really strange to me that Cassandra doesn't support data >>> versioning cause all of other key-value databases support it (at least >>> those who I know). >>> >>> I have one remaining question: >>> -in the case that I have more than 1 SSTable in the disk for the same >>> column but with different data versions, is it possible to make a >>> query to get the old version instead of the newest one? >>> >>> Regards, >>> Felipe Mathias Schmidt >>> (Computer Science UFRGS, RS, Brazil) >>> >>> >>> >>> >>> 2012/5/16 Dave Brosius <dbros...@mebigfatguy.com>: >>> >>> You're in for a world of hurt going down that rabbit hole. If you truely >>> >>> want version data then you should think about changing your keying to >>> >>> perhaps be a composite key where key is of form >>> >>> >>> NaturalKey/VersionId >>> >>> >>> Or if you want the versioning at the column level, use composite columns >>> >>> with ColumnName/VersionId format >>> >>> >>> >>> >>> >>> On 05/16/2012 10:16 AM, Felipe Schmidt wrote: >>> >>> >>> That was very helpfull, thank you very much! >>> >>> >>> I still have some questions: >>> >>> -it is possible to make Cassandra keep old value data after flushing? >>> >>> The same question for the memTable, before flushing. Seems to me that >>> >>> when I update some tuple, the old data will be overwrited in memTable, >>> >>> even before flushing. >>> >>> -it is possible to scan values from the memtable, maybe using the >>> >>> so-called Thrift API? Using the client-api I can just see the newest >>> >>> data version, I can't see what's really happening with the memTable. >>> >>> >>> I ask that cause what I'll try to do is a Change Data Capture to >>> >>> Cassandra and the answers will define what kind of aproaches I'm able >>> >>> to use. >>> >>> >>> Thanks in advance. >>> >>> >>> Regards, >>> >>> Felipe Mathias Schmidt >>> >>> (Computer Science UFRGS, RS, Brazil) >>> >>> >>> >>> 2012/5/14 aaron morton<aa...@thelastpickle.com>: >>> >>> >>> Cassandra does not provide access to multiple versions of the same >>> >>> column. >>> >>> It is essentially implementation detail. >>> >>> >>> All mutations are written to the commit log in a binary format, see the >>> >>> o.a.c.db.RowMutation.getSerializedBuffer() (If you want to tail it for >>> >>> analysis you may want to change commitlog_sync in cassandra.yaml) >>> >>> >>> Here is post about looking at multiple versions columns in an >>> >>> sstable http://thelastpickle.com/2011/05/15/Deletes-and-Tombstones/ >>> >>> >>> Remember that not all "versions" of a column are written to disk >>> >>> (see http://thelastpickle.com/2011/04/28/Forces-of-Write-and-Read/). >>> >>> Also >>> >>> compaction will compress multiple versions of the same column from >>> >>> multiple >>> >>> files into a single version in a single file . >>> >>> >>> Hope that helps. >>> >>> >>> >>> ----------------- >>> >>> Aaron Morton >>> >>> Freelance Developer >>> >>> @aaronmorton >>> >>> http://www.thelastpickle.com >>> >>> >>> On 14/05/2012, at 9:50 PM, Felipe Schmidt wrote: >>> >>> >>> Yes, I need this information just for academic purposes. >>> >>> >>> So, to read old data values, I tried to open the Commitlog using tail >>> >>> -f and also the log files viewer of Ubuntu, but I can not see many >>> >>> informations inside of the log! >>> >>> Is there any other way to open this log? I didn't find any Cassandra >>> >>> API for this purpose. >>> >>> >>> Thanks averybody in advance. >>> >>> >>> Regards, >>> >>> Felipe Mathias Schmidt >>> >>> (Computer Science UFRGS, RS, Brazil) >>> >>> >>> >>> >>> >>> 2012/5/14 zhangcheng2<zhangche...@software.ict.ac.cn>: >>> >>> >>> After compaciton, the old version data will gone! >>> >>> >>> >>> ________________________________ >>> >>> >>> zhangcheng2 >>> >>> >>> >>> From: Felipe Schmidt >>> >>> >>> Date: 2012-05-14 05:33 >>> >>> >>> To: user >>> >>> >>> Subject: Retrieving old data version for a given row >>> >>> >>> I'm trying to retrieve old data version for some row but it seems not >>> >>> >>> be possible. I'm a beginner with Cassandra and the unique aproach I >>> >>> >>> know is looking to the SSTable in the storage folder, but if I insert >>> >>> >>> some column and right after insert another value to the same row, >>> >>> >>> after flushing, I only get the last value. >>> >>> >>> Is there any way to get the old data version? Obviously, before >>> >>> compaction. >>> >>> >>> >>> Regards, >>> >>> >>> Felipe Mathias Schmidt >>> >>> >>> (Computer Science UFRGS, RS, Brazil) >>> >>> >>> >>> >>> >>> > >
