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gus bjorklund
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> On May 2, 2019, at 5:27 AM, George Potemkin wrote: > > Note that the code of writeprobe above creates only 3 recovery notes per transaction (RL_TBGN, RL_TMSAVE, RL_TEND) there is a slight flaw here. note that the create and the delete were optimized away by the 4GL runtime. what’s left should also be optimized away since no database change was made. but in the real world, this isnt going to happen much. > Can somebody explain when these latches are locked individually and when they are locked under the cover of MTX latch the TXT latch is (mostly) used while holding the MTX latch. same with TXQ. LKT is often not used while also holding MTX some of the other things that can happen while holding MTX are: - writes to before-image log - formatting new before-image cluster - expanding before-image extent - writes to after-image journal - expanding after-image extent - after-image extent switch - writes to database extents - use of BIB latch - use of AIB latch
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