mangalaman93 commented :
We have been working hard behind the scene to figure out a way we can cancel an ongoing index and still have strong consistency semantics in Dgraph. As Manish explained, the challenge in cancelling indexing is that the followed proposal are not seen until index creation is complete i.e. an alpha will not see a proposal for index deletion (i.e. unindexed schema) until the index is fully computed. Looking ahead in the proposal would be complex and possibly inefficient to implement.
What we plan to do instead is to figure out a way to compute the indexes in the background. This has its own challenges too. But once we do this, we can continue applying rest of the proposals while indexes are computed in the background. Now, if rest of the proposals contain proposal for deleting the index (or cancelling the index, i.e. unindexed schema), we could stop the background computation of the index.
We are still working on figuring out a way to compute the indexes in the background. We have a proposal in place, we are executing the proposal and testing the code. I will keep you posted with rest of the progress. Once again, thanks for filling the issue.