Zugg Software :: View topic

Novice Joined: 02 Jun 2007 Posts: 37

Ok, basically im setting all the settings for my system into one big data record, for cleanliness sake, taking 50+ variables like balance, equilibrium etc. and having them located in one place....the problem is When my prompt trigger fires, sometimes it deletes ALL the other settings in data record....This is a bigtime problem, since none of my other scripts will run if those settings arnt present (I also have another data record that keeps track of defences, and it overwrites that as well).......Here's my prompt trigger.

Apprentice Joined: 12 Jul 2004 Posts: 190 Location: Canada

Does your syssetting variable have a "default" value for some reason that's clearing it after each restart of CMud? I know I had a problem with that on one of my variables, and it turned out that was the case... I believe if you recreate the variable with

Novice Joined: 02 Jun 2007 Posts: 37

Ive tried it with and without a default, it resets correctly on the connect, but the first time my prompt fires (which is immediately after I sign in) it rewrites to JUST the Key's and Values from the Prompt Trigger. The #loopdb works, and from then on the values just update, but I would like to know why it rewrites the entire variable on the first prompt.

Posted: Mon Jun 18, 2007 5:09 pm

One thing to keep in mind is that using database variables is not currently very efficient. Database variables are stored as giant string values (sort of like a string list, but with different delimiters between each item). Therefore, when you reference a particular key value in the variable, it needs to scan the entire string looking for that key. So, the larger your database variable gets, the slower it will get.

You'd have faster scripts if you used class folders and regular variables, such as

Novice Joined: 02 Jun 2007 Posts: 37

Hmmm....I didnt even think of that Shocked

. Well, creating all the individual variables was easy enough (hooray for #loopdb) now i just gotta go back and change the variable calls in the script......Im still curious as to why it rewrites the record though, as I think im going to use the Data Record for certain key settings, like packnumbers that need updating regularly and such.

Wizard Joined: 25 Mar 2003 Posts: 1113 Location: USA

Posted: Tue Jun 19, 2007 7:21 pm

With the current design, it would be quite hard. It's the same reason the database module isn't a real SQL database. When the database module is rewritten, then you will see more efficient database variables (or maybe the Lua scripting will make all of this a moot point).

The problem is that all zMUD variables are stored internally as string values. CMUD expands upon this by also allowing a variable to have an integer or floating-point "cache". In other words, the value is still stored as a string, but if it represents an Integer, then the Integer value is cached to avoid repetitious string conversions (something that makes CMUD a bit faster than zMUD).

But variables still only store those simple types: string, integer, float. And everything needs to be able to be represented by a string value in order to be exported and imported via XML.

So, to implement a hash table, I'd still need to convert the hash table to/from a string value and just have it stored as a table when in memory, and then I'd need to modify the variables so that they can hold a pointer to this value (perhaps similar to how I currently hold pointers to COM objects). But since so much of the internal structure of CMUD is based upon string variables, there might be a lot of excessive conversions between the hash table and the string value and that might still cause it to be slow.

However, I shouldn't overstate this problem...database variables are still quite fast and are certainly not going to be a bottle neck. There are so many other areas in zMUD/CMUD that limit performance of scripting that I'm not saying everyone should convert their scripts. Database variables *are* convenient and should still be used in many cases. I didn't mean to open up a "can of worms" here, but sometimes people are interested in the low level details and whether A or B is faster. Just because B is faster doesn't mean A isn't useful.

Wizard Joined: 25 Mar 2003 Posts: 1113 Location: USA

Thanks, Zugg, for the detailed explanation. I can see very well what you mean about storing things in the SQLite as a string. I don't know if it will be more efficient to serialize the data record variables as binary data when the real database module comes along.

As you say, though, they're not the big bottleneck for scripting in CMUD, and so I'll continue using my methods and believing that what I'm doing is for the best. It's certainly very readable, flexible, and more easily maintainable to use data record variables in so many situations. I'm really just glad they exist. I'll be interested to see how the Lua integration turns out and whether I should move more towards Lua tables for certain types of data manipulation.