From: | Andrew Dunstan <andrew(at)dunslane(dot)net> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | simon(at)2ndquadrant(dot)com, pgman(at)candle(dot)pha(dot)pa(dot)us, kleptog(at)svana(dot)org, gsstark(at)mit(dot)edu, pg(at)rbt(dot)ca, zhouqq(at)cs(dot)toronto(dot)edu, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: [Bizgres-general] WAL bypass for INSERT, UPDATE and |
Date: | 2005-12-30 17:39:21 |
Message-ID: | 43B570C9.6060406@dunslane.net |
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Lists: | pgsql-hackers |
Tom Lane wrote:
>"Andrew Dunstan" <andrew(at)dunslane(dot)net> writes:
>
>
>>Simon Riggs said:
>>
>>
>>>Following Andrew's concerns, I'd also note that ALTER TABLE requires a
>>>much higher level of privilege to operate than does COPY. That sounds
>>>like it will make things more secure, but all it does is open up the
>>>administrative rights, since full ownership rights must be obtained
>>>merely to load data.
>>>
>>>
>
>
>
>>My concern is more about making plain that this is for special operations,
>>not normal operations. Or maybe I have misunderstood the purpose.
>>
>>
>
>Rephrase that as "full ownership rights must be obtained to load data in
>a way that requires dropping any existing indexes and locking out other
>users of the table". I don't think the use-case for this will be very
>large for non-owners, or indeed even for owners except during initial
>table creation; and so I don't think the above argument is strong.
>
>
>
>
Those restrictions aren't true of Bruce's proposed drop and
delete/truncate recovery modes, are they?
People do crazy things in pursuit of performance. Illustration: a few
months ago I was instrumenting an app (based on MySQL/ISAM) and I
noticed that under load it simply didn't update the inventory properly -
of 1000 orders placed within a few seconds it might reduce inventory by
3 or 4. I reported this and they shrugged their shoulders and said
"well, we'd have to lock the table and that would slow everything down
...".
I just want to be sure we aren't providing a footgun. "Oh, just set
recovery mode to delete. It won't make any difference unless you crash
and you'll run faster."
cheers
andrew
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