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Displaying posts with tag: InnoDB Performance Transaction (reset)
Transaction life cycle improvements in 5.7.3

This is part of the ongoing work on improving the transaction life cycle management. In 5.7.2 we split the transaction list into two. The read-only transaction list and the read-write transaction list. There was another “virtual” list, the auto-commit non-locking read-only (AC-NL-RO) transaction list. The change in 5.7.2 was that by default a transaction was treated as read only and added to the read-only transaction list. Only when it was determined that the transaction was going to do an update we removed the transaction from the read-only list and moved it to the read-write transaction list. This initial add to the the read-only list forced the acquisition of the trx_sys_t::mutex. Acquiring the mutex during transaction start/begin has a cost. Promoting a transaction from read-only to read-write we had to acquire the trx_sys_t::mutex to add to the read-write transaction list and so that is not too expensive and is unavoidable. There is another …

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