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From "Marcus Eriksson (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (CASSANDRA-14261) Compaction Profiling Improvements
Date Thu, 12 Apr 2018 12:36:00 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-14261?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16435468#comment-16435468
] 

Marcus Eriksson edited comment on CASSANDRA-14261 at 4/12/18 12:35 PM:
-----------------------------------------------------------------------

this lgtm, but I don't think the {{isCounterColumn}} change is correct - it seems super columns
with counters are represented as a map with counter values, like this (in 3.0, upgraded from
2.1):
{code}
cqlsh> describe sc.counters;                                                          
                                                                                         
          
CREATE TABLE sc.counters (
    key text,
    column1 text,
    column2 blob,
    "" map<blob, counter>,
    value counter,
    PRIMARY KEY (key, column1, column2)
) WITH COMPACT STORAGE
    AND CLUSTERING ORDER BY (column1 ASC, column2 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',
'max_threshold': '32', 'min_threshold': '4'}
    AND compression = {'chunk_length_in_kb': '64', 'class': 'org.apache.cassandra.io.compress.LZ4Compressor'}
    AND crc_check_chance = 1.0
    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 = 'NONE';
{code}

the "for thrift" comment should be removed though


was (Author: krummas):
this lgtm, but I don't think the {{isCounterColumn}} change is correct - it seems super columns
with counters are represented as a map with counter values, like this (in 3.0, upgraded from
2.1):
{code}
cqlsh> describe sc.counters;                                                          
                                                                                         
          
CREATE TABLE sc.counters (
    key text,
    column1 text,
    column2 blob,
    "" map<blob, counter>,
    value counter,
    PRIMARY KEY (key, column1, column2)
) WITH COMPACT STORAGE
    AND CLUSTERING ORDER BY (column1 ASC, column2 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',
'max_threshold': '32', 'min_threshold': '4'}
    AND compression = {'chunk_length_in_kb': '64', 'class': 'org.apache.cassandra.io.compress.LZ4Compressor'}
    AND crc_check_chance = 1.0
    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 = 'NONE';
{code}

> Compaction Profiling Improvements
> ---------------------------------
>
>                 Key: CASSANDRA-14261
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-14261
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Compaction
>            Reporter: Jeff Jirsa
>            Assignee: Jeff Jirsa
>            Priority: Minor
>             Fix For: 4.x
>
>         Attachments: patched-hot-threads.png, patched-tlab.png, unpatched-hot-threads-top.png,
unpatched-hot-threads.png, unpatched-tlab.png
>
>
> There's some low hanging fruit in some laptop compaction runs, such as creating a ton
of the same object unnecessarily and hashing cell names repeatedly to see if a column is dropped
even when we should know that the table has no dropped columns. 



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