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From Brian Burruss <bburr...@real.com>
Subject read latency creaping up
Date Sun, 13 Dec 2009 21:14:57 GMT
i've noticed the longer i let my test clients run the higher the read latency becomes.  if
i kill the clients, the latency drops back down to a reasonable value.  write latency isn't
affected.  here are two cfstats listings from the same machine, the first before and the second
after i killed the clients.  i do not touch the servers.  this seems odd.  if the clients
are doing some bad, it seems that the server's latency wouldn't be affected.  is this a thrift
issue?  

before
---------


Keyspace: uds
	Read Count: 2003
	Read Latency: 59.807 ms.
	Write Count: 65145
	Write Latency: 0.047 ms.
	Pending Tasks: 0
		Column Family: bucket
		Memtable Columns Count: 168751
		Memtable Data Size: 351695390
		Memtable Switch Count: 94
		Read Count: 2003
		Read Latency: 59.807 ms.
		Write Count: 65176
		Write Latency: 0.047 ms.
		Pending Tasks: 0


after
-------

Keyspace: uds
	Read Count: 53249
	Read Latency: 3.653 ms.
	Write Count: 52888
	Write Latency: 0.035 ms.
	Pending Tasks: 0
		Column Family: bucket
		Memtable Columns Count: 383297
		Memtable Data Size: 798864312
		Memtable Switch Count: 94
		Read Count: 53271
		Read Latency: 3.649 ms.
		Write Count: 52937
		Write Latency: 0.035 ms.
		Pending Tasks: 0

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