Re: Secondary Indexes C* 3.0
To provide more context, I was going through this https://docs.datastax.com/en/cql/3.3/cql/cql_using/useWhenIndex.html#useWhenIndex__highCardCol On Thu, Feb 22, 2018 at 9:35 AM, Akash Gangil wrote: > Hi, > > I was wondering if there are recommendations around the cardinality of > secondary indexes. > > As I understand an index on a column with many distinct values will be > inefficient. Is it because the index would only direct me to the specfic > sstable, but then it sequentially searches for the target records? So a > wide range of the index could lead to a lot of ssltable options to traverse? > > Though what's unclear is what the recommended (or benchmarked?) limit, is > it the index must have 100 distinct values, or can it have upto 1000 or > 5 distinct values? > > thanks! > > > > > -- > Akash > -- Akash
Re: Secondary Indexes C* 3.0
Read this: http://www.doanduyhai.com/blog/?p=13191 On Thu, Feb 22, 2018 at 6:44 PM, Akash Gangil wrote: > To provide more context, I was going through this > https://docs.datastax.com/en/cql/3.3/cql/cql_using/useWhenIndex.html# > useWhenIndex__highCardCol > > On Thu, Feb 22, 2018 at 9:35 AM, Akash Gangil > wrote: > >> Hi, >> >> I was wondering if there are recommendations around the cardinality of >> secondary indexes. >> >> As I understand an index on a column with many distinct values will be >> inefficient. Is it because the index would only direct me to the specfic >> sstable, but then it sequentially searches for the target records? So a >> wide range of the index could lead to a lot of ssltable options to traverse? >> >> Though what's unclear is what the recommended (or benchmarked?) limit, is >> it the index must have 100 distinct values, or can it have upto 1000 or >> 5 distinct values? >> >> thanks! >> >> >> >> >> -- >> Akash >> > > > > -- > Akash >
RE: Secondary Indexes C* 3.0
A very interesting and detailed article, thank you DuyHai. I think this should be part of general Cassandra documentation. -- Jacques-Henri Berthemet From: DuyHai Doan [mailto:doanduy...@gmail.com] Sent: Thursday, February 22, 2018 7:04 PM To: user Subject: Re: Secondary Indexes C* 3.0 Read this: http://www.doanduyhai.com/blog/?p=13191<http://www.doanduyhai.com/blog/?p=13191> On Thu, Feb 22, 2018 at 6:44 PM, Akash Gangil mailto:akashg1...@gmail.com>> wrote: To provide more context, I was going through this https://docs.datastax.com/en/cql/3.3/cql/cql_using/useWhenIndex.html#useWhenIndex__highCardCol<https://docs.datastax.com/en/cql/3.3/cql/cql_using/useWhenIndex.html#useWhenIndex__highCardCol> On Thu, Feb 22, 2018 at 9:35 AM, Akash Gangil mailto:akashg1...@gmail.com>> wrote: Hi, I was wondering if there are recommendations around the cardinality of secondary indexes. As I understand an index on a column with many distinct values will be inefficient. Is it because the index would only direct me to the specfic sstable, but then it sequentially searches for the target records? So a wide range of the index could lead to a lot of ssltable options to traverse? Though what's unclear is what the recommended (or benchmarked?) limit, is it the index must have 100 distinct values, or can it have upto 1000 or 5 distinct values? thanks! -- Akash -- Akash
