Le jeudi 7 juin 2012 09:53:48, Nir Zilberman a écrit : > Hi. > > We are handling multiple concurrent clients connecting to our system - > trying to get a license seat (each license has an initial capacity of > seats). We have a table which keeps count of the acquired seats for each > license. When a client tries to acquire a seat we first make sure that the > number of acquired seats is less than the license capacity. We then > increase the number of acquired seats by 1. > > Our main problem here is with the acquired seats table. > It is actually a shared resource which needs to be updated concurrently by > multiple transactions. > > When multiple transactions are running concurrently - each transaction > takes a long time to complete because it waits on the lock for the shared > resource table. > > Any suggestions for better implementation/design of this feature would be > much appreciated. maybe you can manage something around UNIQUE (license_id,license_seat_number). It depends of what you achieve, and the tables structures you have. -- Cédric Villemain +33 (0)6 20 30 22 52 http://2ndQuadrant.fr/ PostgreSQL: Support 24x7 - Développement, Expertise et Formation
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