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https://issues.apache.org/jira/browse/CASSANDRA-6527?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yuki Morishita updated CASSANDRA-6527:
--------------------------------------
Attachment: 6527-2.0.txt
(also: https://github.com/yukim/cassandra/commits/6527)
Patch as well as test case attached.
> Random tombstones after adding a CF with sstableloader
> ------------------------------------------------------
>
> Key: CASSANDRA-6527
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6527
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Bartłomiej Romański
> Priority: Critical
> Fix For: 2.0.4
>
> Attachments: 6527-2.0.txt
>
>
> I've marked this bug as critical since it results in a data loss without any
> warnings.
> Here's the scenario:
> - create a fresh one-node cluster with cassandra 1.2.11
> - add a sample row:
> {code}
> CREATE KEYSPACE keyspace1 WITH replication = {'class':'SimpleStrategy',
> 'replication_factor':1};
> use keyspace1;
> create table table1 (key text primary key, value1 text);
> update table1 set value1 = 'some-value' where key = 'some-key';
> {code}
> - flush, drain, shutdown the cluster - you should have a single sstable:
> {code}
> root@l1:~# ls /var/lib/cassandra/data/keyspace1/table1/
> keyspace1-table1-ic-1-CompressionInfo.db
> keyspace1-table1-ic-1-Filter.db
> keyspace1-table1-ic-1-Statistics.db
> keyspace1-table1-ic-1-TOC.txt
> keyspace1-table1-ic-1-Data.db
> keyspace1-table1-ic-1-Index.db
> keyspace1-table1-ic-1-Summary.db
> {code}
> with a perfectly correct content:
> {code}
> root@l1:~# sstable2json
> /var/lib/cassandra/data/keyspace1/table1/keyspace1-table1-ic-1-Data.db
> [
> {"key": "736f6d652d6b6579","columns": [["","",1387822268786000],
> ["value1","some-value",1387822268786000]]}
> ]
> {code}
> - create a new cluster with 2.0.3 (we've used 3 nodes with replication=2, but
> I guess it doesn't matter)
> - copy sstable from the machine in the old cluster to one of the machines in
> the new cluster (we do not want to use old sstableloader)
> - load sstables with sstableloader:
> {code}
> sstableloader -d 172.16.9.12 keyspace1/table1
> {code}
> - analyze the content of newly loaded sstable:
> {code}
> root@l13:~# sstable2json
> /var/lib/cassandra/data/keyspace1/table1/keyspace1-table1-jb-1-Data.db
> [
> {"key": "736f6d652d6b6579","metadata": {"deletionInfo":
> {"markedForDeleteAt":294205259775,"localDeletionTime":0}},"columns":
> [["","",1387824835597000], ["value1","some-value",1387824835597000]]}
> ]
> {code}
> There's a random tombstone inserted!
> We've hit this bug in production. We never use delete for this column family,
> but the tombstones appeared for each row. The timestamp looks random. In our
> case it was mostly in past, but sometimes (about 3% rows) it was in the
> future. That's even worse than missing a row. In that case you cannot simply
> add it again - tombstone from the future will hide it.
> Fortunately, we have noticed that quickly and canceled the migration.
> However, we were quite lucky. There are no warnings or errors during the
> whole process. Losing less than 3% of data may be hard to noticed at first
> sight for many kind of apps.
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