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https://issues.apache.org/jira/browse/CASSANDRA-14013?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16251160#comment-16251160
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Vincent White commented on CASSANDRA-14013:
-------------------------------------------
I took a look at this today and found the cause of this issue. It is indeed
that the name "snapshots" is causing confusion as C* tries to retrieve the
keyspace and column family names from the file paths here:
{code:java| title=org.apache.cassandra.io.sstable.Descriptor#fromFilename()}
else if
(cfDirectory.getParentFile().getName().equals(Directories.SNAPSHOT_SUBDIR))
{
cfDirectory = cfDirectory.getParentFile().getParentFile();
}
cfname = cfDirectory.getName().split("-")[0] + indexName;
ksname = cfDirectory.getParentFile().getName();
{code}
I wrote a quick patch
[here|https://github.com/vincewhite/cassandra/commits/14013-test] and would
really appreciate some suggestions on improving it (or a different approach). I
didn't have a chance to test 3.0.x but the code at least in this area appears
to be the same. I should have time to tidy this up and add a test this week.
Cheers,
-vince
> Data loss in snapshots keyspace after service restart
> -----------------------------------------------------
>
> Key: CASSANDRA-14013
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14013
> Project: Cassandra
> Issue Type: Bug
> Reporter: Gregor Uhlenheuer
>
> I am posting this bug in hope to discover the stupid mistake I am doing
> because I can't imagine a reasonable answer for the behavior I see right now
> :-)
> In short words, I do observe data loss in a keyspace called *snapshots* after
> restarting the Cassandra service. Say I do have 1000 records in a table
> called *snapshots.test_idx* then after restart the table has less entries or
> is even empty.
> My kind of "mysterious" observation is that it happens only in a keyspace
> called *snapshots*...
> h3. Steps to reproduce
> These steps to reproduce show the described behavior in "most" attempts (not
> every single time though).
> {code}
> # create keyspace
> CREATE KEYSPACE snapshots WITH replication = {'class': 'SimpleStrategy',
> 'replication_factor': 1};
> # create table
> CREATE TABLE snapshots.test_idx (key text, seqno bigint, primary key(key));
> # insert some test data
> INSERT INTO snapshots.test_idx (key,seqno) values ('key1', 1);
> ...
> INSERT INTO snapshots.test_idx (key,seqno) values ('key1000', 1000);
> # count entries
> SELECT count(*) FROM snapshots.test_idx;
> 1000
> # restart service
> kill <cassandra-pid>
> cassandra -f
> # count entries
> SELECT count(*) FROM snapshots.test_idx;
> 0
> {code}
> I hope someone can point me to the obvious mistake I am doing :-)
> This happened to me using both Cassandra 3.9 and 3.11.0
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