On Thu, Jul 9, 2015 at 4:49 PM, Jeff Janes <jeff.janes@gmail.com> wrote: > Is there anything in the below section which has been been implemented or > rendered irrelevant by BRIN indexes? > > https://wiki.postgresql.org/wiki/Todo#Indexes > > "Consider smaller indexes that record a range of values per heap page, > rather than having one index entry for every heap row"
[ catching up on old threads ]
BRIN is exactly this, isn't it? Well, moreso: it's a range of values for a range of heap pages.
It's close, but not the same.
BRIN is a summary index and so could never support uniqueness.
It's also possible to have an index type that has a precise TID entry, yet a more compact format, which would then allow unique values. This would be similar to the way SQLServer compresses primary key indexes.
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Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services