RE: [firebird-support] Re: How to "shape" indexes to avoid index depth > 3

2019-01-30 Thread 'Leyne, Sean' s...@broadviewsoftware.com [firebird-support]
> > the multi-segment indexes are to optimize commonly used queries. > >In this case you can consider removing one or two fields from the index and > see how much selectivity it lose and how much performance would be > affected. So, you are saying that having less fields reduces the index

Re: [firebird-support] Re: How to "shape" indexes to avoid index depth > 3

2019-01-29 Thread Dimitry Sibiryakov s...@ibphoenix.com [firebird-support]
29.01.2019 21:13, 'Leyne, Sean' s...@broadviewsoftware.com [firebird-support] wrote: > the multi-segment indexes are to optimize commonly used queries. In this case you can consider removing one or two fields from the index and see how much selectivity it lose and how much performance would

RE: [firebird-support] Re: How to "shape" indexes to avoid index depth > 3

2019-01-29 Thread 'Leyne, Sean' s...@broadviewsoftware.com [firebird-support]
> > All the FB articles/docs/postings that I have seen have said for > > performance, index depth should be no more than 3. > > This is not a hard requirement, 4 levels may be also OK. Are those multi- > segment indices primary/unique keys or just for lookup purposes? {Sorry for the delay in