WAL and Re: MySQL's (false?) claims... (was: Re: PL/java?)
От | Dr. Evil |
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Тема | WAL and Re: MySQL's (false?) claims... (was: Re: PL/java?) |
Дата | |
Msg-id | 20010826070834.16849.qmail@sidereal.kz обсуждение исходный текст |
Ответ на | Re: MySQL's (false?) claims... (was: Re: PL/java?) (David Ford <david@blue-labs.org>) |
Список | pgsql-general |
You guys shouldn't even be worrying about this. Five years from now, MySQL will be a much more mature product, but the way I see it now is this: MySQL: Great for message boards (Slashdot), information retrieval (an on-line phone directory that's mostly static), or other lightweight applications. PG7.1: Great for doing more commercial type things: inventories, accounting, and business in general, but it does lack some of the high-end DB features, particularly replication and clustering, and also some performance optimizations, which make it not quite in the big-leagues yet. Oracle: Great for everything beyond PG7.1. MS-SQL: Use this one if you desperately need Western currency and want to "lose" some plutonium! PG7.2: It finally has replication! This makes it a strong competitor to Oracle for most applications. Why is replication so important? If the data you are dealing with are valuable, you simply cannot trust them to one machine. Machines catch on fire, buildings burn down, earthquakes happen, lightning strikes. A disaster can happen any time, anywhere. The only solution to this is replication. Until PG has it, it can't be trusted with really valuable data. One thing which I would like to see in addition to replication is an enhanced WAL mechanism. Right now WAL only writes to a log file. That's fine, but I can see two other things that WAL could do very easily, which would be great for financial users, or others who deal with valuable data: One is sending the tuple, as a string, off to another server somewhere to be logged, perhaps in another DB of some kind. That way, when Server #1 gets struck by lightning, no problem, not a single transaction has been lost. This wouldn't take any major mods to the WAL system; if someone would tell me where to look in the code, I'll do it myself. The second WAL change would be to allow WAL to send output to a plain old dot matrix printer. Yes, it's a primitive thing to do, but again, if you are dealing with financial transactions, sometimes it's a wonderful thing to be able to have them in a human-readable read-only format. No amount of elite hacking can undo something which has been printed. This technique, as primitive as it sounds, is used all over the place. Ever notice that when you put your ATM card in the machine, you often hear a printer going? Everything is logged the old-fashioned way. Again, if someone will point me to the place in the WAL code where it has the tuple and it wants to write it out, I'll make these mods myself.
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