i thought about doing that be is obviously a bit more complicated. thx
for confirming the problem.
On 08/25/2010 09:58 AM, Jonathan Ellis wrote:
in many cases, especially "give me the first column", slicing is
faster -- lots of tombstones around is one case where it might not be.
if you can
in many cases, especially "give me the first column", slicing is
faster -- lots of tombstones around is one case where it might not be.
if you can reduce the tombstone volume, say by switching to a new row
every 5 minutes, that would help a lot.
On Wed, Aug 25, 2010 at 11:43 AM, B. Todd Burruss
i did check sstables, and there are only three. i haven't done any
major compacts.
do u think it is taking so long because it must sift thru the deleted
columns before compaction?
so accessing a column by name instead of slice predicate is faster?
On 08/24/2010 11:23 PM, Benjamin Black wro
Cassandra doesn't deserialize entire rows to read a single column.
On Tue, Aug 24, 2010 at 11:25 PM, Artie Copeland wrote:
> Have you tried using a super column, it seems that having a row with over
> 100K columns and growing would be alot for cassandra to deserialize? what
> is iostat and jmete
Todd,
This is a really bad idea. What you are likely doing is spreading
that single row across a large number of sstables. The more columns
you insert, the more sstables you are likely inspecting, the longer
the get_slice operations will take. You can test whether this is so
by running nodetool
thx artie,
i haven't used a super CF because i thought it has more trouble doing
slices because the entire row must be deserialized to get to the
subcolumn you want?
iostat is nothing, 0.0. i have plenty of RAM and the OS is I/O caching
nicely
i haven't used the key cache, because i only
Have you tried using a super column, it seems that having a row with over
100K columns and growing would be alot for cassandra to deserialize? what
is iostat and jmeter telling you? it would be interesting to see that data.
also what are you using for you key or row caching? do you need to use a
i am using get_slice to pull columns from a row to emulate a queue.
column names are TimeUUID and the values are small, < 32 bytes. simple
ColumnFamily.
i am using SlicePredicate like this to pull the first ("oldest") column
in the row:
SlicePredicate predicate = new SlicePredicate
