Re: On Scalability

2010/10/7 Simon Riggs <simon(at)2ndquadrant(dot)com>:
> On Thu, 2010-10-07 at 14:10 +0200, Vincenzo Romano wrote:
>
>> Making these things sub-linear (whether not O(log n) or even O(1) ),
>> provided that there's  way to, would make this RDBMS more appealing
>> to enterprises.
>> I mean also partial indexes (as an alternative to table partitioning).
>> Being able to effectively cope with "a dozen child tables or so" it's more
>> like an amateur feature.
>> If you really need partitioning (or just hierarchical stuff) I think you'll need
>> for quite more than a dozen items.
>> If you partition by just weeks, you'll need 50+ a year.
>>
>> Is there any precise direction to where look into the code for it?
>>
>> Is there a way to put this into a wish list?
>
> It's already on the wish list ("TODO") and has been for many years.
>
> We've mostly lacked somebody with the experience and time/funding to
> complete that implementation work. I figure I'll be doing it for 9.2
> now; it may be difficult to do this for next release.
>
> Theoretically, this can be O(n.log n) for range partitioning and O(1)
> for exact value partitioning, though the latter isn't a frequent use
> case.
>
> Your conclusion that the current partitioning only works with a dozen or
> so items doesn't match the experience of current users however.
>
> --
>  Simon Riggs           www.2ndQuadrant.com
>  PostgreSQL Development, 24x7 Support, Training and Services
>

Do the same conclusions apply to partial indexes?
I mean, if I have a large number (n>=100 or n>=1000) of partial indexes
on a single very large table (m>=10**12), how good is the planner to choose the
right indexes to plan a query?
Has also this algorithm superlinear complexity?

--
Vincenzo Romano at NotOrAnd Information Technologies
Software Hardware Networking Training Support Security
--
NON QVIETIS MARIBVS NAVTA PERITVS