Re: MySQL ResultSet - count rows?

Arne Vajhøj wrote:
Lew wrote:
Dyreatnews@xxxxxxx wrote:
Ruud is making a very good point. I've just been told that the the
SELECT COUNT(*) approach will only be guaranteed to work if you execute
both SELECTs in a single transaction AND use SERIALIZABLE isolation
level. Even at REPEATABLE READ you may see new rows added since the
previous select, (but all rows counted will have the same value
throughout the transaction).

You won't "see" those new rows added until after the transaction completes.

You will.

user 1 - SELECT COUNT(*)
user 2 - INSERT
user 1 - SELECT

Only SERIALIZABLE will prevent this.

I stand corrected. Thanks, Dyreatnews and Arne.

--
Lew
.

Relevant Pages

  • Re: MySQL ResultSet - count rows?
    ... Lew wrote: ... SELECT COUNTapproach will only be guaranteed to work if you execute ... both SELECTs in a single transaction AND use SERIALIZABLE isolation ...
    (comp.lang.java.databases)
  • Re: MySQL ResultSet - count rows?
    ... SELECT COUNTapproach will only be guaranteed to work if you execute ... both SELECTs in a single transaction AND use SERIALIZABLE isolation ...
    (comp.lang.java.databases)
  • Re: MySQL ResultSet - count rows?
    ... SELECT COUNTapproach will only be guaranteed to work if you execute ... both SELECTs in a single transaction AND use SERIALIZABLE isolation ...
    (comp.lang.java.databases)