A few days ago I was in the middle of writing up a quick post about a query performance problem I recently ran into. The writeup referenced predicate selectivity, and I found myself wondering whether everyone who came across the post would have a good intuitive understanding of what that referred to. Just in case,…
Month: January 2011
Living with SQL’s 900 Byte Index Key Length Limit
We recently had a situation where we needed to interface with an external non-relational data source that happened to use really long strings to identify entity instances. These identity strings had theoretically unbounded length, but in practice they were never more than 1000-2000 characters. The database layer needed to accept an identifier of this sort…