Untagging CentralAuth since it doesn't directly write to the ipblocks table, if the other uses of INSERT IGNORE in CA are a problem please file separate tasks for those.

INSERT IGNORE is primarily used to try prevent duplicates, while INSERT will return an error on duplicate entries INSERT IGNORE will issue a warning and discard the entry.

Technically insert ignore should have stopped all the duplicates, an alternative can be using a REPLACE however since this deletes the previous duplicate row before inserting it might cause on cascade/referential constraint issues.

We could try one one the 2 in code,

1. Manually check if row exists before inserting then skip if it does (essentially INSERT IGNORE that is code driven) or
2. Try to run an INSERT but put it in a try catch and just issue a continue on duplicate key error and log other errors.

Tested using try catch doesn't work since we get this error `Cannot execute query from MediaWiki\Block\DatabaseBlockStore::insertBlock while transaction status is ERROR```
so probably the reason we used ignore, since it will not generate any DB errors.

Manually check if row exists before inserting then skip if it does (essentially INSERT IGNORE that is code driven) or

It sounds like this is a safe option for getting rid of the INSERT IGNORE. @Niharika - anything to add?

I discussed this task with @LSobanski and they are inclined towards us picking up this work at our leisure (preferably after SecurePoll).
We can repurpose this into an actionable ticket and add it to our backlog.