[ZODB-Dev] Advice needed

2006-06-23 Thread Adam Groszer
Hi there, I know it is not easy, but I need some advices to keep our bosses happy at the planning stage of our application. The application we are planning is a document management application which follows documents in a company. Document and version count could be around 1s, quite frequent

Re: [ZODB-Dev] Advice needed

2006-06-23 Thread Andreas Jung
--On 23. Juni 2006 14:27:52 +0200 Adam Groszer <[EMAIL PROTECTED]> wrote: Hi there, I know it is not easy, but I need some advices to keep our bosses happy at the planning stage of our application. The application we are planning is a document management application which follows documents i

[ZODB-Dev] Re: What makes the ZODB slow?

2006-06-23 Thread Florent Guillaume
Roché Compaan wrote: I love the ZODB, and I am sure that I don't have to explain why, to anybody on this list. I love it so much that it often clouds my judgement. Sometimes I really should be using a relational backend but I don't - the ZODB is just too convenient, and I don't have to complicate

Re[2]: [ZODB-Dev] Advice needed

2006-06-23 Thread Adam Groszer
Hi Andreas, Thank you for your quick answer. Friday, June 23, 2006, 2:36:56 PM, you wrote: AJ> --On 23. Juni 2006 14:27:52 +0200 Adam Groszer <[EMAIL PROTECTED]> wrote: >> Hi there, >> >> I know it is not easy, but I need some advices to keep our bosses >> happy at the planning stage of our ap

Re: Re[2]: [ZODB-Dev] Advice needed

2006-06-23 Thread Andreas Jung
--On 23. Juni 2006 16:05:49 +0200 Adam Groszer <[EMAIL PROTECTED]> wrote: AJ> We run a CMS with several ZEO storages using FileStorage with up 300k AJ> different objects per storage. May you mention some or some sites on the internet that run Zope/ZODB to have some examples? Since ZODB is

Re: [ZODB-Dev] Re: What makes the ZODB slow?

2006-06-23 Thread Jean Jordaan
> The ZODB is actually very fast. [...] > > So you're probably observing slowness in the frameworks on top of it. I'll believe this anytime :-] In our case, a transaction may be a workflow state change on say 50 objects. Two or three people try a transaction like that within a couple of seconds

[ZODB-Dev] Re: What makes the ZODB slow?

2006-06-23 Thread Florent Guillaume
Jean Jordaan wrote: The ZODB is actually very fast. [...] So you're probably observing slowness in the frameworks on top of it. I'll believe this anytime :-] In our case, a transaction may be a workflow state change on say 50 objects. Two or three people try a transaction like that within a c

Re: [ZODB-Dev] Re: What makes the ZODB slow?

2006-06-23 Thread Andreas Jung
--On 23. Juni 2006 17:51:35 +0200 Florent Guillaume <[EMAIL PROTECTED]> wrote: BTrees perform best when keys' prefixes are randomly distributed. So if your application generates keys like 'foo001', 'foo002',... you'll get lots of conflicts. Same for consecutive integers in IOBTree. hm..

Re: [ZODB-Dev] Re: What makes the ZODB slow?

2006-06-23 Thread Roché Compaan
On Fri, 2006-06-23 at 15:11 +0200, Florent Guillaume wrote: > > I often daydream of a ZODB that will one day have such great performance > > that it won't be necessary to adopt a hybrid backend. I know there is a > > huge difference between objects and records in an RDBMS, but in an > > attempt to

Re: [ZODB-Dev] Re: What makes the ZODB slow?

2006-06-23 Thread Florent Guillaume
On 23 Jun 2006, at 17:55, Andreas Jung wrote: --On 23. Juni 2006 17:51:35 +0200 Florent Guillaume <[EMAIL PROTECTED]> wrote: BTrees perform best when keys' prefixes are randomly distributed. So if your application generates keys like 'foo001', 'foo002',... you'll get lots of conflicts. Same

Re: [ZODB-Dev] Re: What makes the ZODB slow?

2006-06-23 Thread Dieter Maurer
Jean Jordaan wrote at 2006-6-23 16:24 +0200: > ... write conflicts by large transactions ... >To mitigate this, we want to create a savepoint and then commit more often >while iterating and changing workflow, rolling back to the savepoint if >necessary. I fear this will not work -- at least not wh

Re: [ZODB-Dev] What makes the ZODB slow?

2006-06-23 Thread Dieter Maurer
Roché Compaan wrote at 2006-6-22 21:53 +0200: > ... >What overhead does undo add to performance? Very few -- apart from a fast growing storage file. However, the log behaviour of "FileStorage" means that you get a very different notion of locallity. In a relational database, records in the same

Re: [ZODB-Dev] Advice needed

2006-06-23 Thread Dieter Maurer
Adam Groszer wrote at 2006-6-23 14:27 +0200: > ... >Some fears they are having and I can't find unambiguous information: >- Is ZODB a good choice for this app? It depends... At least careful design is necessary! The most problematic aspects of the ZODB are write conflicts. When two concurrent

Re: [ZODB-Dev] What makes the ZODB slow?

2006-06-23 Thread Roché Compaan
On Fri, 2006-06-23 at 21:02 +0200, Dieter Maurer wrote: > Roché Compaan wrote at 2006-6-22 21:53 +0200: > > ... > >What overhead does undo add to performance? > > Very few -- apart from a fast growing storage file. > > However, the log behaviour of "FileStorage" means that > you get a very differ

Re: [ZODB-Dev] Advice needed

2006-06-23 Thread Roché Compaan
On Fri, 2006-06-23 at 22:03 +0200, Dieter Maurer wrote: > Adam Groszer wrote at 2006-6-23 14:27 +0200: > > ... > >Some fears they are having and I can't find unambiguous information: > >- Is ZODB a good choice for this app? > > It depends... > At least careful design is necessary! > > The most pr