Hey there – Like other suggested before adding more index , look for opportunity to de-normalize your data model OR create composite keys for your primary index – if that works for you. Secondary index are there so you can leverage them they come with cost. They’re difficult to manage , as you repair data your secondary index will NOT be automatically repaired so you’ll need to maintain them On each cluster node. Depending on size of your cluster that could be a significant effort. Be prepared to rebuild your new index (nodetool rebuild_index) as often as you change the data . performance will eventually get a hit cause index rebuilding is expensive operation on CPU ..
See please http://docs.datastax.com/en/cql/3.1/cql/ddl/ddl_when_use_index_c.html From: techpyaasa . [mailto:techpya...@gmail.com] Sent: Tuesday, June 20, 2017 2:30 AM To: ZAIDI, ASAD A <az1...@att.com> Cc: user@cassandra.apache.org Subject: Re: Secondary Index Hi ZAIDI, Thanks for reply. Sorry I didn't get your line "You can get away the potential situation by leveraging composite key, if that is possible for you?" How can I get through it?? Like I have a table as below CREATE TABLE ks1.cf1 (id1 bigint, id2 bigint, resp text, status int, PRIMARY KEY (id1, id2) ) WITH CLUSTERING ORDER BY (id2 ASC) 'status' will have values of 0/1/2/3/4 (4 possible values) , insertions to table(partition) will happen based on id2 i.e values(id1,id2,resp,status) I want to have a filtering/criteria applied on 'status' column too like select * from ks1.cf1 where id1=123 and status=0; How can I achieve this w/o secondary index (on 'status' column )?? On Tue, Jun 20, 2017 at 12:09 AM, ZAIDI, ASAD A <az1...@att.com<mailto:az1...@att.com>> wrote: If you’re only creating index so that your query work, think again! You’ll be storing secondary index on each node , queries involving index could create issues (slowness!!) down the road the when index on multiple node Is involved and not maintained! Tables involving a lot of inserts/delete could easily ruin index performance. You can get away the potential situation by leveraging composite key, if that is possible for you? From: techpyaasa . [mailto:techpya...@gmail.com<mailto:techpya...@gmail.com>] Sent: Monday, June 19, 2017 1:01 PM To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> Subject: Secondary Index Hi, I want to create Index on already existing table which has more than 3 GB/node. We are using c*-2.1.17 with 2 DCs , each DC with 3 groups and each group has 7 nodes.(Total 42 nodes in cluster) So is it ok to create Index on this table now or will it have any problem? If its ok , how much time it would take for this process? Thanks in advance, TechPyaasa
