not resolved
Anonymous
Unregistered
Hello I have a problem with the stress tool.
I've played this:
stress -d 127.0.0.1 -n 100000
no problem
then I do stress -d 127.0.0.1 -o read
and here I have many error messages like this one:
Operation [15] retried 10 times - error reading key 0526289
and at the end:
0,0,0,NaN,2
I'm running cassandra 1.0.8 under debian suqeeze and java 1.6.
Does it should work?
thx
Anonymous
Unregistered
stress -d 127.0.0.1 -n 100000
will write rows with key values 000000-099999, when you then do
stress -d 127.0.0.1 -o read
without a -n, it is defaulting to -n 1000000, which will try to read keys 0000000-0999999 (notice the extra digit). Switch your stress read to:
stress -d 127.0.0.1 -o read -n 100000
and see if that works for you.
Anonymous
Unregistered
Well I did not know that but even with a
stress -d 127.0.0.1 -o read -n 1 it does not work:
total,interval_op_rate,interval_key_rate,avg_latency,elapsed_time
Operation [0] retried 10 times - error reading key 0
0,0,0,NaN,0
END
I'm sure data are in the DB.
thx
Anonymous
Unregistered
Did you try -o read -n 100000? The issue isn't that you were trying to read with a different n, it's that you were trying to read with an n which has a different order of magnitude. When trying to read -n 1, see that it was trying to read key 0? That key doesn't exist from a -n 100000 insert, since it will have only inserted keys 000000-099999.
To explain it more generally and without so many confusing sets of zeroes...
If you go into Data Explorer in OpsCenter, or simply do a list CF in cassandra-cli, you'll see that each key generated by a -o insert -n x will have the same number of digits as x does. This is the problem you're running into when trying to -o read -n y. If y doesn't have the same number of digits as x, the read will fail as it's trying to access keys that don't exist.
In general, you'll want to only use the stress -o read with the same -n you used during the insert. The farthest you can deviate from this would be to -o insert -n 9999 and then -o read -n 1000 (And similar 9...9->100...0 patterns), since they have the same number of digits they will both be accessing the same keys.
If you have lots of problem from stress just take meditation 5-10 min after that you feel very well.
You must log in to post.
