[MEVD] Consider renaming IsFilterable to IsIndexed

[roji]

First, some database allow filtering on any property, regardless of whether it has an index or not; this is the case e.g. with relational databases, where index can speed up queries but are never required. For those databases, IsFilterable doesn't express what the property actually does. We should consider renaming for this to simply indicate what it does (trigger index creation).

Second, indexes can speed up operations other than filtering, notably sorting/ordering performed by non-vector searches (#10295).

/cc @westey-m @dmytrostruk @adamsitnik

[adamsitnik]

Regarding the ordering, Azure AI Search exposes two properties for that: IsFilterable (which we already use) and IsSortable (which we don't as of today)

https://github.com/Azure/azure-sdk-for-net/blob/8d28a4cfdecd29611e5595ae24f11ad67270df45/sdk/search/Azure.Search.Documents/src/Indexes/Models/SimpleField.cs#L36-L43

https://github.com/Azure/azure-sdk-for-net/blob/8d28a4cfdecd29611e5595ae24f11ad67270df45/sdk/search/Azure.Search.Documents/src/Indexes/Models/SimpleField.cs#L54-L60

[roji]

Interesting, I wonder what that means in terms of the actual database indexes used (presumably it has two different index types to drive each operation or something? Am not familiar with that from other databases).

Assuming we rename IsFilterable to IsIndexed in MEVD, we could make that setting trigger both IsFilterable and IsSortable on Azure AI Search; later, we could expose connector-specific extensions to allow managing this in a more fine-grained way... How does that sound?

[adamsitnik]

How does that sound?

It sounds good to me, but do we have any contacts to the Azure AI Search Team? We could ensure that it's not some kind of anti-pattern.

[shethaadit]

Hi @roji / @adamsitnik / @markwallace-microsoft, I have raised PR for this - #11167.

[roji]

It sounds good to me, but do we have any contacts to the Azure AI Search Team? We could ensure that it's not some kind of anti-pattern.

I don't, but I think maybe @westey-m does - in any case we need to hear his opinion about this first.

@shethaadit thanks for the PR, but we'll need to confirm that this is the way we want to go first.

[westey-m]

@roji Sounds like a reasonable change. The initial naming was heavily inspired by the Azure AI Search naming, but you are right in that IsIndexed definitely matches the behavior of this property much better. We may want to reconsider the IsFullTextSearchable property at the same time as well.

[roji]

Good point about IsFullTextSearchable... AFAIK in at least some (most?) databases, full-text indexes are are different beast from plain indexes (since they need to take lemmatization and other language stuff into account); that may be a good reason to maintain both.

[westey-m]

Yeah, I just meant naming wise. We should consider whether to rename it to IsFullTextIndexed. Similar to the other one it would match what we actually do a bit better.