I have gone through link for reindexing with zero downtime.
There is no information for handling live updates going on into old index.
Solution thought were:
Queue updated and deletes and update new index with these instruction when reindexing is done.
(Issue i can see with this as it does not update old index, my current search queries will not be up to date).
Keep performing live updates on old index as well as keep queueing. When i am done with reindex, reissue queues command to new index.
(Issue in this , there can be data inconsistencies).
I can't use old index for reindex into new index as my old document did not contain some new fields. I always will be needing to reindex from source of truth (sql). Again as this sql db is getting updated at a high rate, how i can reindex to new elasticsearch index?
It will be really helpful if i can get some pointers.
Thanks in advance.