RE: [DISCUSS] Improve Commitlog write path

[Public] Thank you Bowen for your reply. Took some time to respond due to testing issue. I tested again multi-threaded feature with number of records from 260 million to 2 billion and still improvement is seen around 80% of Ramdisk score. It is still possible that compaction can become new bott

Re: [DISCUSS] Improve Commitlog write path

Hi Amit, I am inclined to agree with Bowen Song, in that benchmarks from an initially empty cluster tend to lean more heavily on memtable and commit log bottlenecks than a real-world long running cluster does, as the algorithmic complexity of LSMTs begin to bite much later while the cost of the

Re: [DISCUSS] Improve Commitlog write path

Hi Amit, The compaction bottleneck is not an instantly visible limitation. It in effect limits the total size of writes over a fairly long period of time, because compaction is asynchronous and can be queued. That means if compaction can't keep up with the writes, they will be queued, and Ca

Re: [DISCUSS] Improve Commitlog write path

When thinking about compaction vs commit log bottlenecks, there would be very different profiles between TWCS vs STCS as well as for transient tables with short TTLs which never accumulate large data, but have heavy I/O. Amit's analysis strikes me as insightful. Multi-threading the commit log mig

RE: [DISCUSS] Improve Commitlog write path

[AMD Official Use Only - General] Hi Benedict, The whole point is Cassandra as a software should take advantage of hardware wherever possible. So reducing Commitlog bottleneck may help some workloads and not all. I am already working on trunk now and will share the patch. If changes looks good

Re: CEP-15 multi key transaction syntax

Avi brought up an interesting point around NULLness checking in CASSANDRA-17762 ... In SQL, any comparison with NULL is NULL, which is interpreted as FALSE in > a condition. To test for NULLness, you use IS NULL or IS NOT NULL. But LWT > uses

Grant Read-Only access on Production Cassandra Keyspace

Hi, There is a requirement to grant Read-Only access to dev team on Production Cassandra Keyspace. In RDS MySQL, we can leverage Read-Replica so that dev can run queries without causing any performance issue on live database. How can I grant read-only access on Cassandra keyspace and also ensu

Re: [DISCUSS] Improve Commitlog write path

Amit, welcome and thank you for contributing the results from your test and opening this discussion.I don’t think anyone is arguing that the database shouldn’t take advantage of available hardware.A few things important to keep in mind when considering a patch like this:- Where the actual bottlenec

Re: Grant Read-Only access on Production Cassandra Keyspace

Hi Bhavesh, In order to control the access to cassandra, you need to enable authentication and authorization in cassandra. However, both are disabled in a10 cassandra, so I don't have much experience on this requirement. Thanks, Guang From: Bhavesh Prajapati

RE: [DISCUSS] Improve Commitlog write path

[AMD Official Use Only - General] Hi Scott, Thank you for your reply. I didn’t mean to argue and sorry if it appeared that way. I see that compaction is a complex activity once the data grows too big and definitely at some peak point improvement will go away due to some factors on some worklo