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https://issues.apache.org/jira/browse/CASSANDRA-2628?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13032443#comment-13032443
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Jonathan Ellis commented on CASSANDRA-2628:
-------------------------------------------
To clarify, the problem is that since slice is inclusive-from-start, if our
page size is one a 2nd pass will get back the same row the first did, so the
scan logic thinks there is no more data and breaks. (since that is exactly what
you will see if you just scanned the last column in the index row.)
+1 on the fix.
> Empty Result with Secondary Index Queries with "limit 1"
> --------------------------------------------------------
>
> Key: CASSANDRA-2628
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2628
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 0.7.5
> Environment: CentOS 5.5
> Reporter: Muga Nishizawa
> Assignee: Sylvain Lebresne
> Fix For: 0.7.6
>
> Attachments: 0001-2628.patch
>
>
> Empty result is returned by secondary index queries with "limit 1".
> Cassandra returns correct result for other numbers than "1" (e.g. limit 2,
> limit 3, etc.).
> You can reproduce the problem with programs attached on CASSANDRA-2406.
> - 1. Start Cassandra cluster. It consists of 3 cassandra nodes and
> distributes data by ByteOrderedPartitioner. Initial tokens of those nodes are
> ["31", "32", "33"].
> - 2. Create keyspace and column family, according to "create_table.cli",
> - 3. Execute "secondary_index_insertv2.py", inserting a few hundred columns
> to cluster
> - 4. Here, when you first use cassandra-cli and execute following lines, you
> can get correct result.
> {quote}
> % bin/cassandra-cli
> [default@unknown] connect localhost/9160;
> [default@unknown] use SampleKS;
> [default@SampleKS] get SampleCF where up = 'up' limit 3;
> -------------------
> RowKey: 150
> => (column=date, value=150, timestamp=1304937931)
> => (column=up, value=up, timestamp=1304937931)
> -------------------
> RowKey: 151
> => (column=date, value=151, timestamp=1304937932)
> => (column=up, value=up, timestamp=1304937932)
> -------------------
> RowKey: 152
> => (column=date, value=152, timestamp=1304937932)
> => (column=up, value=up, timestamp=1304937932)
> 3 Rows Returned.
> {quote}
> On the other hand, if you set limit to "1", you can reproduce the problem.
> {quote}
> [default@SampleKS] get SampleCF where up = 'up' and date > 150 limit 1;
> 0 Row Returned.
> {quote}
> There are two factors to cause this problem:
> - 1. scanned first column doesn't match at specified clause like "date > 150".
> - 2. "limit 1"
> Only one factor doesn't cause problem. For example, I can get correct data
> when I specify as following:
> - "limit 1" -> "limit 2"
> {quote}
> [default@SampleKS] get SampleCF where up = 'up' and date > 150 limit 2;
> -------------------
> RowKey: 151
> => (column=date, value=151, timestamp=1304937932)
> => (column=up, value=up, timestamp=1304937932)
> -------------------
> RowKey: 152
> => (column=date, value=152, timestamp=1304937932)
> => (column=up, value=up, timestamp=1304937932)
> 2 Rows Returned.
> {quote}
> - "date > 150" -> "date >= 150"
> {quote}
> [default@SampleKS] get SampleCF where up = 'up' and date >= 150 limit 1;
> -------------------
> RowKey: 150
> => (column=date, value=150, timestamp=1304937931)
> => (column=up, value=up, timestamp=1304937931)
> 1 Row Returned.
> {quote}
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