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From Yang <teddyyyy...@gmail.com>
Subject is it possible for light-traffic CF to hold down many commit logs?
Date Fri, 23 Sep 2011 01:45:21 GMT
in 1.0.0  we don't have memtable_throughput for each individual CF ,
and instead
which memtable/CF to flush is determined by "largest
getTotalMemtableLiveSize() ".
(MeteredFlusher.java line 81)


what would happen in the following case ? : I have only 2 CF, the
traffic for one CF is 1000 times that
of the second CF,
so the high-traffic CF constantly triggers total mem threshold , and
every time, the busy CF is flushed.

but the light-traffic CF is never flushed ( well, until we have
flushed about 1000 times the busy CF),
now we are left with many commit logs , each of them containing a few
entries for the light-traffic table. we have to keep these commit logs
because these entries are not flushed to sstable yet.

then there are 2 problems: 1) to persist the few records from the
light-traffic CF, you have to keep 1000 times the commit logs
necessary, taking up disk space 2) when you do a recover on server
restart, you'll have to read through all those commit logs .

does the above hypothesis sound right?

Thanks
Yang

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