[Lazarus] Web development and XML database (Mattias)

[Juha Manninen]

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.

I in fact created a solution for browsing and searching the PDM data
quickly, using VirtualTreeView + data dumps read into memory.
In many cases the reading should be optimized and fast because it happens
often. Writing can be slow, in most cases nobody cares.

Juha
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lazarus-ide.org/pipermail/lazarus/attachments/20111117/3c47e2e5/attachment-0003.html>