Hello my opinion: @1 can be faster for access to last items with index @2 can be more effective about data files length allocation @1 or @2 - it depends on number of prices per product. For small number (less 100) I am strong for @2 (if speed is important). Personally prefer @2. Pavel 2010/11/16 Louis-David Mitterrand <vindex+lists-pgsql-performance@xxxxxxxxxxx>: > Hi, > > I have to collect lots of prices from web sites and keep track of their > changes. What is the best option? > > 1) one 'price' row per price change: > > Â Â Â Âcreate table price ( > Â Â Â Â Â Â Â Âid_price primary key, > Â Â Â Â Â Â Â Âid_product integer references product, > Â Â Â Â Â Â Â Âprice integer > Â Â Â Â); > > 2) a single 'price' row containing all the changes: > > Â Â Â Âcreate table price ( > Â Â Â Â Â Â Â Âid_price primary key, > Â Â Â Â Â Â Â Âid_product integer references product, > Â Â Â Â Â Â Â Âprice integer[] -- prices are 'pushed' on this array as they change > Â Â Â Â); > > Which is bound to give the best performance, knowing I will often need > to access the latest and next-to-latest prices? > > Thanks, > > -- > Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
