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From "Philip Thompson (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CASSANDRA-9540) Cql query doesn't return right information when using IN on columns for some keys
Date Thu, 04 Jun 2015 13:59:38 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-9540?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Philip Thompson updated CASSANDRA-9540:
---------------------------------------
    Assignee: Carl Yeksigian

> Cql query doesn't return right information when using IN on columns for some keys
> ---------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-9540
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9540
>             Project: Cassandra
>          Issue Type: Bug
>          Components: API
>         Environment: Cassandra 2.1.5
>            Reporter: Mathijs Vogelzang
>            Assignee: Carl Yeksigian
>             Fix For: 2.1.x
>
>
> We are investigating a weird issue where one of our clients doesn't get data on his dashboard.
It seems Cassandra is not returning data for a particular key ("brokenkey" from now on).
> Some background:
> We have a row where we store a "metadata" column and data in columns "bucket/0", "bucket/1",
"bucket/2", etc. Depending on the date selection of the UI, we know that we only need to retrieve
bucket/0, bucket/0 and bucket/1 etc. (we always need to retrieve "metadata").
> A typical query may look like this (using SELECT column1 to just show what is returned,
normally we would of course do SELECT value):
> {noformat}
> cqlsh:AppBrain> select blobAsText(column1) from "GroupedSeries" where key=textAsBlob('install/workingkey');
>  blobAsText(column1)
> ---------------------
>             bucket/0
>             metadata
> (2 rows)
> cqlsh:AppBrain> select blobAsText(column1) from "GroupedSeries" where key=textAsBlob('install/brokenkey');
>  blobAsText(column1)
> ---------------------
>             bucket/0
>             metadata
> (2 rows)
> {noformat}
> These two queries work as expected, and return the information that we actually stored.
> However, when we "filter" for certain columns, the brokenkey starts behaving very weird:
> {noformat}
> cqlsh:AppBrain> select blobAsText(column1) from "GroupedSeries" where key=textAsBlob('install/workingkey')
and column1 IN (textAsBlob('metadata'),textAsBlob('bucket/0'),textAsBlob('bucket/1'),textAsBlob('bucket/2'));
>  blobAsText(column1)
> ---------------------
>             bucket/0
>             metadata
> (2 rows)
> cqlsh:AppBrain> select blobAsText(column1) from "GroupedSeries" where key=textAsBlob('install/workingkey')
and column1 IN (textAsBlob('metadata'),textAsBlob('bucket/0'),textAsBlob('bucket/1'),textAsBlob('bucket/2'),textAsBlob('asdfasdfasdf'));
>  blobAsText(column1)
> ---------------------
>             bucket/0
>             metadata
> (2 rows)
> ***  As expected, querying for more information doesn't really matter for the working
key ***
> cqlsh:AppBrain> select blobAsText(column1) from "GroupedSeries" where key=textAsBlob('install/brokenkey')
and column1 IN (textAsBlob('metadata'),textAsBlob('bucket/0'),textAsBlob('bucket/1'),textAsBlob('bucket/2'));
>  blobAsText(column1)
> ---------------------
>             bucket/0
> (1 rows)
> *** Cassandra stops giving us the metadata column when asking for a few more columns!
***
> cqlsh:AppBrain> select blobAsText(column1) from "GroupedSeries" where key=textAsBlob('install/brokenkey')
and column1 IN (textAsBlob('metadata'),textAsBlob('bucket/0'),textAsBlob('bucket/1'),textAsBlob('bucket/2'),textAsBlob('asdfasdfasdf'));
>  key | column1 | value
> -----+---------+-------
> (0 rows)
> *** Adding the bogus column name even makes it return nothing from this row anymore!
***
> {noformat}
> There are at least two rows that malfunction like this in our table (which is quite old
already and has gone through a bunch of Cassandra upgrades). I've upgraded our whole cluster
to 2.1.5 (we were on 2.1.2 when I discovered this problem) and compacted, repaired and scrubbed
this column family, which hasn't helped.
> Our table structure is:
> {noformat}
> cqlsh:AppBrain> describe table "GroupedSeries";
> CREATE TABLE "AppBrain"."GroupedSeries" (
>     key blob,
>     column1 blob,
>     value blob,
>     PRIMARY KEY (key, column1)
> ) WITH COMPACT STORAGE
>     AND CLUSTERING ORDER BY (column1 ASC)
>     AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
>     AND comment = ''
>     AND compaction = {'min_threshold': '4', 'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy',
'max_threshold': '32'}
>     AND compression = {'sstable_compression': 'org.apache.cassandra.io.compress.LZ4Compressor'}
>     AND dclocal_read_repair_chance = 0.1
>     AND default_time_to_live = 0
>     AND gc_grace_seconds = 864000
>     AND max_index_interval = 2048
>     AND memtable_flush_period_in_ms = 0
>     AND min_index_interval = 128
>     AND read_repair_chance = 1.0
>     AND speculative_retry = 'NONE';
> {noformat}
> Let me know if I can give more information that may be helpful.



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