Sitecore Azure index rebuild doesn't work with disabled indexAllFields

Question

After migration from Solr to Azure Search I found the problem with a limited amount of fields for Sitecore indexes: core and master.

In all articles\answers was suggested disabling of indexAllFields property. But after this change rebuild stopped working. Error is:

Message: {"error":{"code":"InvalidRequestParameter","message":"The request is invalid.","details":[{"code":"InvalidScoringProfile","message":"The field named 'boost_2' referenced in the scoring function was not found in the index schema. Parameters: definition"}]}}

I found usage of this field in the Sitecore.ContentSearch.Azure.DefaultIndexConfiguration:

<scoringProfilesRepository type="Sitecore.ContentSearch.Azure.Models.ScoringProfilesRepository, Sitecore.ContentSearch.Azure">
        <activeScoringProfileName>itemboost</activeScoringProfileName>
        <scoringProfiles hint="raw:AddScoringProfile">
          <scoringProfile functionType="magnitude" interpolationType="linear" boostingRangeStart="1" boostingRangeEnd="10" cloudFieldName="boost_2" scoringProfileName="itemboost" scoringProfileBoostValue="10" constantBoostBeyondRange="false" />
        </scoringProfiles>
</scoringProfilesRepository>

So how could I make it work with reduced amount of indexed fields in sitecore indexes?

Answer 1

Finally I reverted indexAllFields setting to true back and tried to rebuild sitecore indexes. After rebuild I got 180 fields for sitecore_core_index.

Also I removed some unnecessary languages in system/languages and it slightly decreased amount of items (from 80000 to 18000) and fields ( from 180 to 110 ) in sitecore_core_index