In Sitecore 9.1.1
The Sitecore_master_index is huge on CM server. It goes up to like 450-500k documents than IIS resets. (think this is because memory dump?)
On Test-environment, which has similar items in master-db, including media library, the result of rebuild sitecore_master_index is only about 60k documents.
Why and what can cause the sitecore_master_index to get so massive?
(I've emptied the recycle bin)
I set the DisableCacheSizeLimits to false and now it completed the rebuild. I also did a Cleanup Database, cleared cache in admin/cache.aspx and cleared the Queues in db.
But i'm not sure if only changing DisableCacheSizeLimits was enough. Before that change, during index rebuild the server was on 99% memory usage for a long time, probably causing the IIS reset.