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Alan Li
05-23-2007, 05:58 PM
Many sql statements may be issued as part of one MDX query in Mondrian. Are
all those sql queries (of a single MDX query) run within the same
transaction?

Alan

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Julian Hyde
05-24-2007, 08:35 PM
Quite a lot of work. Remember that mondrian has a cache and therefore
the cache would either have to be disabled entirely, read-consistency
would need to be extended over all of the statements which populate the
cache, or the user would need to carefully manage the contents of the
cache using the cache control API.

There are other efforts to ensure that mondrian scales to large numbers
of concurrently executing queries, without those queries treating each
other's feet; to make the cache fairer (E.g. a LRU model rather than
garbage-collection); and to be smarter how work is spread between
queries (e.g. combine multiple requests into a SQL statement with uses
the GROUPING SETS construct; and to execute multiple SQL queries in
parallel).

So, the challenge is not only to implement this feature, but to address
the other features as well.

Julian


_____

From: mondrian-bounces (AT) pentaho (DOT) org [mailto:mondrian-bounces (AT) pentaho (DOT) org]
On Behalf Of Alan Li
Sent: Thursday, May 24, 2007 10:22 AM
To: mondrian (AT) pentaho (DOT) org; michael bienstein
Subject: Re : [Mondrian] Transaction semantics of Mondrian


Hi Michael,

How much work would it be to add this functionality to Mondrian?

I can envision it being a configurable mode, where it would be useful
for users that require consistent results in the face of db
update/inserts.

Alan



Date: Thu, 24 May 2007 13:12:19 +0000 (GMT)
From: michael bienstein < mbienstein (AT) yahoo (DOT) fr>
Subject: Re : [Mondrian] Transaction semantics of Mondrian
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