concatenated indexes deliver faster results as concatenated indexes do not require the resultsets to be merged provided the more selective column of the concatenated index is first and least selective column of the concatenated index is last http://webglobalnet.net/support/index.php?topic=864.0
HTH Martin Gainty “I shall take all the troubles of the past, all the disappointments, all the headaches, and I shall pack them in a bag and toss them in the East River.” - Trygve Lie ______________________________________________ Note de déni et de confidentialité Ce message est confidentiel et peut être privilégié. Si vous n'êtes pas le destinataire prévu, nous te demandons avec bonté que pour satisfaire informez l'expéditeur. N'importe quelle diffusion non autorisée ou la copie de ceci est interdite. Ce message sert à l'information seulement et n'aura pas n'importe quel effet légalement obligatoire. Étant donné que les email peuvent facilement être sujets à la manipulation, nous ne pouvons accepter aucune responsabilité pour le contenu fourni. > Date: Thu, 22 Apr 2010 23:36:51 +0200 > From: b...@havleik.no > To: pgsql-general@postgresql.org > Subject: [GENERAL] Creating indexes? > > What is the best approach for PostgreSQL when creating indexes? E.g I have > two fields in a table that I want indexed, is it best to create one index > combining the two fields or creating one for each field? If I create one for > each field, will the search when using both fields be slower that a > combined index? > > > Regards, > > BTJ > > -- > ----------------------------------------------------------------------------------------------- > Bjørn T Johansen > > b...@havleik.no > ----------------------------------------------------------------------------------------------- > Someone wrote: > "I understand that if you play a Windows CD backwards you hear strange > Satanic messages" > To which someone replied: > "It's even worse than that; play it forwards and it installs Windows" > ----------------------------------------------------------------------------------------------- > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general _________________________________________________________________ Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_2
