[Lazarus] Web development and XML database (Mattias)
zeljko at holobit.net
Thu Nov 17 11:55:49 CET 2011
On Thursday 17 of November 2011 11:52:39 michael.vancanneyt at wisa.be wrote:
> On Thu, 17 Nov 2011, Juha Manninen wrote:
> > 2011/11/17 <michael.vancanneyt at wisa.be>
> >> I really don't see why you think SQL databases are slow. We have lots of
> >> queries running on our system, huge amounts of updates, and Firebird
> >> does an extremely good job of it, and we do almost only multi-table
> >> select queries. Concurrency is not an issue at all with their
> >> multi-generational architecture - no locking is needed.
> > I believe your DBs are fast but I have seen really slow ones. I think the
> > complexity of queries, the amount of data and amount of users are the key
> > factors.
> > The delayed response of many web-sites is caused by slow DB access, not
> > by slow program code or slow network connection.
> > In a big company I was involved with PDM, eMatrix object DB which was
> > built on top of Oracle relational DB. It created mystical table
> > structure for the objects. Normal queries took seconds but if your query
> > would return tens of thousands of items it practically halted and the
> > process had to be killed. Another DB was an Oracle ERP. It also had
> > complex table structure and lots of data, and queries typically took
> > seconds. It was running in a computer that was the fastest in our
> > country when it was bought!
> > The table indexes could not be wrong because many people had optimized
> > them.
> That is a VERY dangerous statement :-)
Seen Oracle DB designed with varchars as primary keys, same db ported to pgsql
(redesigned same database by me), using ints as primary keys (so indexes too)
x100 faster (some complex queries (and those are cca 3-4k chars with 10-20
joins and 2-3 subselects) dropped down from 10 minutes into reasonable 10
And ,yes many "programmers" "optimized" that oracle db :)
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