Jiri Kuthan wrote:
At 19:39 03/12/2007, SIP wrote:
On the flip side of having to do more modifications for integration, of course, is that we get the ABILITY to do more modifications.
SER 0.9.6 wasn't limited, per se, but certain aspects of what we've implemented (user-configurable timers, number-based AND uri-based call blocking, call forwarding, call return, whitelisting number mode, etc) in 0.9.6 has felt like a complete and total hack because of the way it has had to be done using a mish mash of AVPs. We're HOPING we can forego some of that with the new SER using the new db queries and such, as well as being able to better-implement some functionality of other RFCs using the more flexible core.
But yes... integration with the new db schema is proving to be a pain in the left ventricle if only because it's so totally focused around optimisation for SER.
The question to me is whether this pain is really specific to current release of the data model (which I apparently don't think so) or to do the burden of migration from the previous. IMO, it is the latter, to be compensated by extensibility which minimizes future migration burden.
I disagree entirely that it's strictly based on migration.
Let's look at the simple act of adding information to the system:
With a flat subscriber table with all the fields I desire, adding information to the system is 1 insert. Let's say that my subscriber table looks like this (because in the dev ser 0.9.6 box, it does):
+-------------------+--------------+------+-----+---------------------+-------+ | Field | Type | Null | Key | Default | Extra | +-------------------+--------------+------+-----+---------------------+-------+ | phplib_id | varchar(32) | NO | UNI | | | | username | varchar(64) | NO | PRI | | | | domain | varchar(128) | NO | PRI | | | | password | varchar(25) | NO | | | | | first_name | varchar(25) | NO | | | | | last_name | varchar(45) | NO | | | | | phone | varchar(15) | NO | | | | | email_address | varchar(50) | NO | | | | | datetime_created | datetime | NO | | 0000-00-00 00:00:00 | | | datetime_modified | timestamp | NO | | CURRENT_TIMESTAMP | | | confirmation | varchar(64) | NO | | | | | flag | char(1) | NO | | o | | | sendnotification | varchar(50) | NO | | | | | greeting | varchar(50) | NO | | | | | ha1 | varchar(128) | NO | | | | | ha1b | varchar(128) | NO | | | | | allow_find | char(1) | NO | | 0 | | | timezone | varchar(128) | YES | | NULL | | | rpid | varchar(128) | YES | | NULL | | | domn | int(10) | YES | | NULL | | | uuid | varchar(64) | YES | | NULL | | | signup_ip | varchar(15) | NO | | | | +-------------------+--------------+------+-----+---------------------+-------+
Now... ignoring the fact that we have 1 possibly 2 unused fields in that table, let's assume we have to add a user in the new schema.
That's 22 inserts right there (one for each attribute, especially since we can't have defaults).
Searching through data? Let's say I want to know the first_name,last_name,username,domain,confirmation, and the datetime_modified of a user. Simple enough. That's 1 query. If any of those data points were null or their default, grabbing that is still easy as can be.
Now... in the new schema, that's a join (which IS less efficient than a query, I'm afraid, though I can't quote exact meaningful metrics on how much). If any of those data points are not SET (assuming we were going to minimise our impact by NOT doing a full 22-insert creation for each user), it causes yet another series of headaches. When you want to reference data in other relations, it becomes even MORE of a hassle. The queries themselves become these unwieldy beasts that increase the chance of an error in syntax or logic.
One of the simplest queries we have is with our admin interface to query who's logged in in such a way that the data will be used in the web interface:
select username, first_name, last_name, signup_ip from subscriber where username=ANY (select username from location);
Simple. Succinct. Clear.We grab the fields we need and can format them. One short line.
Now I'll leave the new schema version as an exercise for the reader, as I don't recall the syntax right off (which is the first clue as to its added complexity). It's lengthy and utterly non-relational -- which is why we simply don't USE it for these sorts of things.
This is not just a migration headache. This is a schema problem. Now, I know you love your schema, and you're allowed, and I fully understand that it's flexible and good for the SER service. But for integration with any sort of system beyond the most basic, it's a right pain in the ass. You can tout its joys and wonders all you'd like, but we're developing with it, and I can assure you, it's not as easy and as straightforward as you like to believe.
I'm not saying there's anything wrong with the schema overall. There have been some great forward leaps in this one, such as the riddance of the incredibly tiresome domain column in every table (that was sometimes checked and sometimes not). But it DOES make for additional complexity when building a system around it.
N.