Do not remove indexes not declared in code

[ondrejtucny]

When there are extra indexes declared for a table, do not delete them. At least introduce an option, which will tolerate unknown indexes. This is important when manual performance tuning is done by the DBA in large-scale installations.

[alex-kulakov]

DataObjects.Net has a way to ignore tables and columns, probably we could expand this to support indexes as well (ignoring by prefix of name or exact name).

[LookBehind]

@alex-kulakov we also need this feature, both for columns and indexes.
should "existing column ignoring" done by upgrade handlers ?

[alex-kulakov]

@LookBehind , No. Take a look at DomainConfiguration.IgnoreRules, now these rules filter tables/table columns on very low level. So the idea is to expand this feature to support indexes. If you are familiar with DO sources you can take a look at Xtensive.Orm.Tests.Storage.IgnoreRulesValidateTest for examples of how these rules might be configured.

[alex-kulakov]

By the way, @LookBehind , you probably need this feature in master but feature requester expects it to be in 6.0 as I understand it.

[LookBehind]

thanks for the link.
master is version 7?

[alex-kulakov]

@LookBehind , master is going to be 7.1, the version is in Version.props file in repository root.

[ondrejtucny]

@alex-kulakov we can't upgrade any dependencies this year, so the earliest I can is January 2022, in which case we will have time to test and hence should be able to upgrade to the latest 7.x.

[alex-kulakov]

@ondrejtucny yep, as I said 6.0 is highly desirable, I understood that from another issue about index performance

[ondrejtucny]

@alex-kulakov what I mean is that I can live with version 7 :) No need to back-port to 6.x.

[alex-kulakov]

So we're free to implement it in 7.1 (current master), right?

[LookBehind]

a quick question: if the column is ignored by your pointed way - will the index that was put on that column be removed by DO during upgrade or not?

[alex-kulakov]

a quick question: if the column is ignored by your pointed way - will the index that was put on that column be removed by DO during upgrade or not?

If you look at the IgnoreRulesHandler class, you can see that it removes some indexes on table if an ignored column is part of this index, also foreign keys can be removed.

[ondrejtucny]

Is this going to make it to 7.1? Btw. what's the expected timeline for 7.1 and .NET 6 support?

[alex-kulakov]

I'll try to make it happen before 7.1 become ready-to-release.

Speaking of Net6 support, it is already in master, dotnet build -c Release will provide you packages with binaries for both frameworks.

We're accumulating certain improvements to make DO faster, these include some API changes which, to my mind, should happen before final release, I assume we will have at least one Beta because changes are significant and we want to give it time and wait for some problems appear. We will probably publish next Beta in September/October