DSN Isolation Level effects

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DSN Isolation Level effects
	Details:
	PROBLEM DESCRIPTION: What are the Locking effects on records based on the different DSN Isolation Levels? PROBLEM RESOLUTION: Below are the results of testing the 5 different DSN Isolation levels using MSAccess, all while monitoring the Lock table via Promon. The 5 DSN Isolation levels are: Blank Isolation, Read Uncommitted, Read Committed, Repeatable Read, Serializable. Of these 5 below is the outcome and a log file for each showing the Lock Table reaction and flag. Blank = Exclusive (EXCL) Lock on all records Read Uncommitted = No lock, lock table remains blank Read Committed = No lock, lock table remains blank Repeatable Read = Mix of Exclusive and Share Locks (EXCL and SHR) Serializable = An "SIX" lock on table 0 To keep your add hoc reports from locking up your system, make sure ALL of your workstation and server DSN's are set to Read Uncommitted. For information on how to set the default isolation level in a query or through a connection string, please see documents 7780MPS and 7786MPS.
	Attachments:
	DSN Isolation = Blank DNS Isolation = Read Committed DSN Isolation = Read Uncommitted DSN Isolation = Repeatable Read DSN Isolation = Serializable