START TRANSACTION

[Frank Natoli]

After START TRANSACTION but before COMMIT, are intervening SQL transactions
visible to other threads or processes? I understand that failing to perform
a COMMIT, or explicitly performing a ROLLBACK, results in the transactions
occurring after START TRANSACTION being undone. But until and if the
transactions are undone, would queries to the database reveal those
transactions? Thanks.

[Good Man]

"Frank Natoli" <fr*********@worldnet.att.net.nospam> wrote in
news:zN***************@newsread3.news.atl.earthlin k.net:

After START TRANSACTION but before COMMIT, are intervening SQL
transactions visible to other threads or processes? I understand that
failing to perform a COMMIT, or explicitly performing a ROLLBACK,
results in the transactions occurring after START TRANSACTION being
undone. But until and if the transactions are undone, would queries to
the database reveal those transactions? Thanks.

nope.

[Bill Karwin]

Frank Natoli wrote:

After START TRANSACTION but before COMMIT, are intervening SQL transactions
visible to other threads or processes? I understand that failing to perform
a COMMIT, or explicitly performing a ROLLBACK, results in the transactions
occurring after START TRANSACTION being undone. But until and if the
transactions are undone, would queries to the database reveal those
transactions? Thanks.

If this were so, it would constitute what is called a "dirty read".
That is, being able to view partially finished, uncommitted updates from
another transaction.

According to the documentation, InnoDB does not provide this style of
transaction isolation (if it can be called that).

See http://dev.mysql.com/doc/mysql/en/in...isolation.html
for more information.

Regards,
Bill K.

[Bill Karwin]

Bill Karwin wrote:

If this were so, it would constitute what is called a "dirty read". That
is, being able to view partially finished, uncommitted updates from
another transaction.

According to the documentation, InnoDB does not provide this style of
transaction isolation (if it can be called that).

See http://dev.mysql.com/doc/mysql/en/in...isolation.html
for more information.

Correction: InnoDB does support dirty reads, the keyword is "READ
UNCOMMITTED". See the web page referenced above for usage.

Regards,
Bill K.