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
