[jira] [Updated] (CASSANDRA-11048) JSON queries are not thread safe

[Ivan Ryndin (JIRA)]

 [ 
https://issues.apache.org/jira/browse/CASSANDRA-11048?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Ivan Ryndin updated CASSANDRA-11048:

Attachment: 0001-Fix-thread-unsafe-usage-of-JsonStringEncoder-see-CAS.patch

patch file submitted

> JSON queries are not thread safe
> 
>
> Key: CASSANDRA-11048
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11048
> Project: Cassandra
>  Issue Type: Bug
>Reporter: Sergio Bossa
>Priority: Critical
>  Labels: easyfix, newbie, patch
> Attachments: 
> 0001-Fix-thread-unsafe-usage-of-JsonStringEncoder-see-CAS.patch
>
>
> {{org.apache.cassandra.cql3.Json}} uses a shared instance of 
> {{JsonStringEncoder}} which is not thread safe (see 1), while 
> {{JsonStringEncoder#getInstance()}} should be used (see 2).
> As a consequence, concurrent {{select JSON}} queries often produce wrong 
> (sometimes unreadable) results.
> 1. 
> http://grepcode.com/file/repo1.maven.org/maven2/org.codehaus.jackson/jackson-core-asl/1.9.2/org/codehaus/jackson/io/JsonStringEncoder.java
> 2. 
> http://grepcode.com/file/repo1.maven.org/maven2/org.codehaus.jackson/jackson-core-asl/1.9.2/org/codehaus/jackson/io/JsonStringEncoder.java#JsonStringEncoder.getInstance%28%29



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[jira] [Commented] (CASSANDRA-11044) query under certain partition key takes much more time than expected

[Ivan Ryndin (JIRA)]

[ 
https://issues.apache.org/jira/browse/CASSANDRA-11044?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15109430#comment-15109430
 ] 

Ivan Ryndin commented on CASSANDRA-11044:
-

>From log it looks like most time is spent while merging memtables and 
>sstables. I see that after messages like {{Merging data from memtables and 3 
>sstables}} there is a big time gap before next message in log shows.

> query under certain partition key takes much more time than expected 
> -
>
> Key: CASSANDRA-11044
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11044
> Project: Cassandra
>  Issue Type: Bug
>  Components: Local Write-Read Paths
>Reporter: xiaost
> Attachments: tracing.log
>
>
> In my cluster, all the nodes is under low workload, 
> but query under certain partition key (we found one) takes much more time 
> than expected. 
> we write & updates about 3 times per row in one day,
> reads are much more than writes.
> HARDWARD:
> 6*nodes(E5-2630, 1*ssd with 5GB data)
> TABLE DESCRIBE:
> {noformat}
> CREATE TABLE album.user_updates (
> user_id bigint,
> time_uuid bigint,
> key ascii,
> PRIMARY KEY (user_id, time_uuid)
> ) WITH CLUSTERING ORDER BY (time_uuid ASC)
> AND bloom_filter_fp_chance = 0.01
> AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
> AND comment = ''
> AND compaction = {'class': 
> 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy'}
> 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 = 0.0
> AND speculative_retry = '99.0PERCENTILE';
> {noformat}
> QUERYs:
> {noformat}
> select * from user_updates where user_id = 1432138730701829 limit 100;
> select count(1) from user_updates where user_id = 1432138730701829;
> {noformat}
> RESULT:  (takes about 3.5 minutes)
> {noformat}
>  count
> ---
>   1058
> (1 rows)
> {noformat}
> check attachments for the tracing log 



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