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From "Maor Cohen (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (CASSANDRA-10801) Unexplained inconsistent data with Cassandra 2.1
Date Mon, 21 Dec 2015 11:57:46 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-10801?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15066371#comment-15066371
] 

Maor Cohen edited comment on CASSANDRA-10801 at 12/21/15 11:57 AM:
-------------------------------------------------------------------

Another example (trace2.log):

Rows that was loaded on Dec 17 (4 days before the read attempt). Executed CQL with consistency
level ONE:

1. First query returned no rows. Logs shows that it doesn't send read request to other nodes.
2. Second query also didn't return rows. Read request sent to other nodes. Inconsistency found
by read repair.
3. Last query returned the row.

I don't understand why the first query didn't send request to other nodes while the last one
did. Can someone explain this?


was (Author: maor.cohen):
Another example:

Rows that was loaded on Dec 17 (4 days before the read attempt). Executed CQL with consistency
level ONE:

1. First query returned no rows. Logs shows that it doesn't send read request to other nodes.
2. Second query also didn't return rows. Read request sent to other nodes. Inconsistency found
by read repair.
3. Last query returned the row.

I don't understand why the first query didn't send request to other nodes while the last one
did. Can someone explain this?

> Unexplained inconsistent data with Cassandra 2.1
> ------------------------------------------------
>
>                 Key: CASSANDRA-10801
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10801
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Imri Zvik
>             Fix For: 2.1.x
>
>         Attachments: trace2.log, tracing.log
>
>
> We are experiencing weird behavior which we cannot explain.
> We have a CF, with RF=3, and we are writing and reading data to it with consistency level
of ONE.
> For some reason, we see inconsistent results when querying for data.
> Even for rows that were written a day ago, we're seeing inconsistent results (1 replca
has the data, the two others don't).
> Now, I would expect to see timeouts/dropped mutations, but all relevant counters are
not advancing, and I would also expect hints to fix this inconsistency within minutes, but
yet it doesn't.
> {code}
> cqlsh:testing> SELECT WRITETIME(last_update),site_id, tree_id, individual_id, last_update
FROM testcf WHERE site_id = 229673621 AND tree_id = 9 AND individual_id = 9032483;       
    
>  writetime(last_update) | site_id   | tree_id | individual_id | last_update
> ------------------------+-----------+---------+---------------+-------------
>        1448988343028000 | 229673621 |       9 |       9032483 |  1380912397
> (1 rows)
> cqlsh:testing> SELECT WRITETIME(last_update),site_id, tree_id, individual_id, last_update
FROM testcf WHERE site_id = 229673621 AND tree_id = 9 AND individual_id = 9032483;
> site_id   | tree_id | individual_id | last_update
> -----------+---------+---------------+-------------
> (0 rows)
> cqlsh:testing> SELECT dateof(now()) FROM system.local ;
>  dateof(now())
> --------------------------
>  2015-12-02 14:48:44+0000
> (1 rows)
> {code}
> We are running with Cassandra 2.1.11 with Oracle Java 1.8.0_65-b17



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