[jira] [Comment Edited] (CASSANDRA-8712) Out-of-sync secondary index

["mlowicki (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-8712?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14306835#comment-14306835 ] 

mlowicki edited comment on CASSANDRA-8712 at 2/11/15 7:30 AM:
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[~slebresne] don't have repro steps yet. What I've found on our production though is that index returns always (17340/17340 cases) superset of what we get from table directly without supporting index. After reading www.datastax.com/dev/blog/improving-secondary-index-write-performance-in-1-2 I would suspect that there is problem with removing stale items from the index. What do you think? Should {{rebuild_index}} help with such issue or it just re-adds missing items and do not remove old ones?

Checked and {{rebuild_index}} doesn't fix the index. Still it returns too much data.


was (Author: mlowicki):
[~slebresne] don't have repro steps yet. What I've found on our production though is that index returns always (17340/17340 cases) superset of what we get from table directly without supporting index. After reading www.datastax.com/dev/blog/improving-secondary-index-write-performance-in-1-2 I would suspect that there is problem with removing stale items from the index. What do you think? Should {{rebuild_index}} help with such issue or it just re-adds missing items and do not remove old ones?

> Out-of-sync secondary index
> ---------------------------
>
>                 Key: CASSANDRA-8712
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8712
>             Project: Cassandra
>          Issue Type: Bug
>         Environment: 2.1.2
>            Reporter: mlowicki
>             Fix For: 2.1.3
>
>
> I've such table with index:
> {code}
> CREATE TABLE entity (
>     user_id text,
>     data_type_id int,
>     version bigint,
>     id text,
>     cache_guid text,
>     client_defined_unique_tag text,
>     ctime timestamp,
>     deleted boolean,
>     folder boolean,
>     mtime timestamp,
>     name text,
>     originator_client_item_id text,
>     parent_id text,
>     position blob,
>     server_defined_unique_tag text,
>     specifics blob,
>     PRIMARY KEY (user_id, data_type_id, version, id)
> ) WITH CLUSTERING ORDER BY (data_type_id ASC, version ASC, id ASC)
>     AND bloom_filter_fp_chance = 0.01
>     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 = 0.0
>     AND speculative_retry = '99.0PERCENTILE';
> CREATE INDEX index_entity_parent_id ON entity (parent_id);
> {code}
> It turned out that index became out of sync:
> {code}
> >>> Entity.objects.filter(user_id='255824802', parent_id=parent_id).consistency(6).count()
> 16
>  
> >>> counter = 0
> >>> for e in Entity.objects.filter(user_id='255824802'):
> ...     if e.parent_id and e.parent_id == parent_id:
> ...         counter += 1
> ... 
> >>> counter
> 10
> {code}
> After couple of hours it was fine (at night) but then when user probably started to interact with DB we got the same problem. As a temporary solution we'll try to rebuild indexes from time to time as suggested in http://dev.nuclearrooster.com/2013/01/20/using-nodetool-to-rebuild-secondary-indexes-in-cassandra/
> Launched simple script for checking such anomaly and before rebuilding index for 4024856 folders 10378 had this issue.



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