Re: impact of update operation to read operation

2014-02-10 Thread Benedict Elliott Smith
Also, a major compaction doesn't flush the memtable. If the memtable is still full, reads may take slightly longer as they may have to be merged with any on-disk data before being served. On 10 February 2014 21:18, Tupshin Harper wrote: > You don't mention disks and RAM, but I would assume tha

Re: impact of update operation to read operation

2014-02-10 Thread Tupshin Harper
You don't mention disks and RAM, but I would assume that the additional data meant that you could now cache a lower percentage and that you have to seek on disk more often. -Tupshin On Feb 10, 2014 4:14 PM, "Jiaan Zeng" wrote: > Hi All, > > I am using Cassandra 1.2.4. I wonder if update operati

impact of update operation to read operation

2014-02-10 Thread Jiaan Zeng
Hi All, I am using Cassandra 1.2.4. I wonder if update operation has *permanent* impacts on read operation. Below is the scenario. Previously, a read only workload runs against one column family and has 4000 qps. Later, a read-update mixed workload runs against the same column family. After that