Read Committed | Notes on SQL

Read Committed Snapshot – Another Optimistic Flavour

Steve Hall

August 26, 2015

In a previous article (here) I described how the isolation level read committed works, with some examples. There is also an optimistic version of this – read committed snapshot, which uses row versions. The behaviour of read committed and read committed snapshot is similar and repeating the examples used previously will show the similarities and …

Read Committed – not getting what you expect

Steve Hall

no comments

July 23, 2015

In a previous article I demonstrated how use of READUNCOMMITTED (or the NOLOCK hint) can result in erroneous data, due to page splits. Examples abound of the more common issue with this isolation level, which occur when reading a row that is being updated in another transaction and then rolled back. These so-called ‘dirty reads’ …