Re: Replacement Selection
От | |
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Тема | Re: Replacement Selection |
Дата | |
Msg-id | BAY132-DS29B97B01D7C8267DECC12E6720@phx.gbl обсуждение исходный текст |
Ответ на | Autovacuum and OldestXmin (Simon Riggs <simon@2ndquadrant.com>) |
Ответы |
Re: Replacement Selection
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Список | pgsql-hackers |
> in puttuple_common(), the transition from an internal to external sort is > performed at the bottom of the TSS_INITIAL case in the main switch > statement. The transition? Do we internal sort somewhere else and then external sort here in tuplesort.c? > The function dumptuples() heapifies the in-core tuples (divides the > in-core tuples into initial runs and then advances the state to > TSS_BUILDRUNS). Cannot see where dumptuples() "advances the state to TSS_BUILDRUNS". I expected something like state->status = TSS_BUILDRUNS; executed through dumptuples() > > I recommend you run the code in the debugger on a external-sorting query: > watch two or three tuples go into the heap and you'll get the idea. > > The top of the heap is at state->memtuples[0] the heap goes down from > there. New tuples are added there and the heap is adjusted (Using the > tuplesort_heap_siftup() function). > > -Tim >
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