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https://issues.apache.org/jira/browse/CASSANDRA-6348?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13829445#comment-13829445
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Alex Liu commented on CASSANDRA-6348:
-------------------------------------
It's interesting that if LIMIT clause is in the query, it's timeout, otherwise
it's fine.
{code}
cqlsh:cql3ks> select key, qty, size from cf where qty>498 and color='red' and
size = 'P' allow filtering;
key | qty | size
------------+-----+------
key_910500 | 499 | P
key_35500 | 499 | P
key_945500 | 499 | P
key_420500 | 499 | P
key_140500 | 499 | P
key_630500 | 499 | P
key_210500 | 499 | P
key_805500 | 499 | P
key_700500 | 499 | P
key_735500 | 499 | P
key_385500 | 499 | P
key_175500 | 499 | P
key_455500 | 499 | P
key_245500 | 499 | P
key_770500 | 499 | P
key_875500 | 499 | P
key_70500 | 499 | P
key_980500 | 499 | P
key_280500 | 499 | P
key_105500 | 499 | P
key_525500 | 499 | P
key_665500 | 499 | P
key_595500 | 499 | P
key_315500 | 499 | P
key_490500 | 499 | P
key_350500 | 499 | P
key_500 | 499 | P
key_840500 | 499 | P
key_560500 | 499 | P
cqlsh:cql3ks> select key, qty, size from cf where qty>498 and color='red' and
size = 'P' limit 1 allow filtering;
Request did not complete within rpc_timeout.
{code}
> TimeoutException throws if Cql query allows data filtering and index is too
> big and it can't find the data in base CF after filtering
> --------------------------------------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-6348
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6348
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Alex Liu
> Assignee: Alex Liu
>
> If index row is too big, and filtering can't find the match Cql row in base
> CF, it keep scanning the index row and retrieving base CF until the index row
> is scanned completely which may take too long and thrift server returns
> TimeoutException. This is one of the reasons why we shouldn't index a column
> if the index is too big.
> Multiple indexes merging can resolve the case where there are only EQUAL
> clauses. (CASSANDRA-6048 addresses it).
> If the query has none-EQUAL clauses, we still need do data filtering which
> might lead to timeout exception.
> We can either disable those kind of queries or WARN the user that data
> filtering might lead to timeout exception or OOM.
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