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List: cassandra-user
Subject: Tuning chunk_length_kb in cassandra 2.1.12
From: Jean Carlo <jean.jeancarl48 () gmail ! com>
Date: 2016-01-29 16:26:17
Message-ID: CAHW7YSTmjLStvaDQA7aF55UVqwu1Zkqub+UvhH_DJojxXCLBHg () mail ! gmail ! com
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Hi guys
I want to set the param chunk_length_kb in order to improve the read
latency of my cassandra_stress's test.
This is the table
CREATE TABLE "Keyspace1".standard1 (
key blob PRIMARY KEY,
"C0" blob,
"C1" blob,
"C2" blob,
"C3" blob,
"C4" blob
) WITH bloom_filter_fp_chance = 0.1
AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
AND comment = ''
AND compaction = {'sstable_size_in_mb': '160', 'class':
'org.apache.cassandra.db.compaction.LeveledCompactionStrategy'}
AND compression = {'sstable_compression':
'org.apache.cassandra.io.compress.SnappyCompressor'}
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';
I have 6 columns of type blob. This table is filled by cassandra_stres
admin@cqlsh:Keyspace1> select * from standard1 limit 2;
key |
C0 |
C1 |
C2 |
C3 | C4
------------------------+------------------------------------------------------------- \
-----------+------------------------------------------------------------------------+- \
-----------------------------------------------------------------------+-------------- \
----------------------------------------------------------+------------------------------------------------------------------------
0x4b343050393536353531 |
0xe0e3d68ed1536e4d994aa74860270ac91cf7941acb5eefd925815481298f0d558d4f |
0xa43f78202576f1ccbdf50657792fac06f0ca7c9416ee68a08125c8dce4dfd085131d |
0xab12b06bf64c73e708d1b96fea9badc678303906e3d5f5f96fae7d8092ee0df0c54c |
0x428a157cb598487a1b938bdb6c45b09fad3b6408fddc290a6b332b91426b00ddaeb2 |
0x0583038d881ab25be72155bc3aa5cb9ec3aab8e795601abe63a2b35f48ce1e359f5e
I am having a read latency of ~500 microseconds, I think it takes to much
time comparing to the write latency of ~30 microseconds.
My first clue is to fix the chunk_length_kb to a value close to the size
of the rows in kb
Am I in the right direction? If it is true, how can I compute the size of a
row?
Other question, the value of "Compacted partition" of the command nodetool
cfstats migth give me a value close to the chunk_length_kb ?
Best regards
Jean Carlo
"The best way to predict the future is to invent it" Alan Kay
[Attachment #3 (text/html)]
<div dir="ltr"><div><div>Hi guys<br><br></div>I want to set the param chunk_length_kb \
in order to improve the read latency of my cassandra_stress's \
test.<br><br></div>This is the table<br><br>CREATE TABLE \
"Keyspace1".standard1 (<br> key blob PRIMARY KEY,<br> "C0" \
blob,<br> "C1" blob,<br> "C2" blob,<br> "C3" \
blob,<br> "C4" blob<br>) WITH bloom_filter_fp_chance = 0.1<br> AND \
caching = '{"keys":"ALL", \
"rows_per_partition":"NONE"}'<br> AND comment = \
''<br> AND compaction = {'sstable_size_in_mb': '160', \
'class': 'org.apache.cassandra.db.compaction.LeveledCompactionStrategy'}<br> \
AND compression = {'sstable_compression': \
'org.apache.cassandra.io.compress.SnappyCompressor'}<br> AND \
dclocal_read_repair_chance = 0.1<br> AND default_time_to_live = 0<br> AND \
gc_grace_seconds = 864000<br> AND max_index_interval = 2048<br> AND \
memtable_flush_period_in_ms = 0<br> AND min_index_interval = 128<br> AND \
read_repair_chance = 0.0<br> AND speculative_retry = \
'99.0PERCENTILE';<br><div><div><div><br></div><div>I have 6 columns of type \
blob. This table is filled by cassandra_stres<br><br>admin@cqlsh:Keyspace1> select \
* from standard1 limit 2; <br><br> key | C0 \
| C1 | C2 \
| C3 | \
C4<br>------------------------+------------------------------------------------------- \
-----------------+-------------------------------------------------------------------- \
----+------------------------------------------------------------------------+-------- \
----------------------------------------------------------------+------------------------------------------------------------------------<br> \
0x4b343050393536353531 | \
0xe0e3d68ed1536e4d994aa74860270ac91cf7941acb5eefd925815481298f0d558d4f | \
0xa43f78202576f1ccbdf50657792fac06f0ca7c9416ee68a08125c8dce4dfd085131d | \
0xab12b06bf64c73e708d1b96fea9badc678303906e3d5f5f96fae7d8092ee0df0c54c | \
0x428a157cb598487a1b938bdb6c45b09fad3b6408fddc290a6b332b91426b00ddaeb2 | \
0x0583038d881ab25be72155bc3aa5cb9ec3aab8e795601abe63a2b35f48ce1e359f5e<br><br></div><div>I \
am having a read latency of ~500 microseconds, I think it takes to much time \
comparing to the write latency of ~30 microseconds.<br><br></div><div>My first clue \
is to fix the chunk_length_kb to a value close to the size of the rows in \
kb<br><br></div><div>Am I in the right direction? If it is true, how can I compute \
the size of a row?<br></div><div><br></div><div>Other question, the value of \
"Compacted partition" of the command nodetool cfstats migth give me a value \
close to the chunk_length_kb ?<br></div><div><font size="2"><br>Best \
regards<br></font><div style="border-collapse:collapse"><span \
style="border-collapse:collapse"><span style="border-collapse:separate"><font \
face="arial, helvetica, sans-serif" size="2"><br>Jean \
Carlo</font></span></span></div><font face="arial, helvetica, sans-serif" \
size="2"><br>"The best way to predict the future is to invent it" Alan \
Kay</font><br></div><div><div><div><div class="gmail_signature"><div \
dir="ltr"></div></div></div> </div></div></div></div></div>
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