Re: Repeatable Read Isolation Level "transaction start time"

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Wizard Brony <wizardbrony(at)gmail(dot)com>
Cc: pgsql-general(at)lists(dot)postgresql(dot)org
Subject: Re: Repeatable Read Isolation Level "transaction start time"
Date: 2024-09-24 14:28:46
Message-ID: 3346993.1727188126@sss.pgh.pa.us
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Wizard Brony <wizardbrony(at)gmail(dot)com> writes:
> But in my testing, I find that according to that statement, the transaction start time is actually "the start of the first non-transaction-control statement in the transaction" (as mentioned earlier in the section). Is my conclusion correct, or am I misunderstanding the documentation?

It's even looser than that, really: it's the first statement that
requires an MVCC snapshot. From memory, LOCK TABLE is an important
exception --- you can acquire table locks before pinning down
a snapshot, and this is important in some scenarios.

regards, tom lane

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