Hi, On 2021-09-01 11:34:34 +0900, Fujii Masao wrote: > On 2021/09/01 0:53, Andres Freund wrote: > > Of course, we need to be careful to not weaken WAL validity checking too > > much. How about the following: > > > > If we're "aborting" a continued record, we set XLP_FIRST_IS_ABORTED_PARTIAL > > on > > the page at which we do so (i.e. the page after the valid end of the WAL). > > When do you expect that XLP_FIRST_IS_ABORTED_PARTIAL is set? It's set > when recovery finds a a partially-flushed segment-spanning record? > But maybe we cannot do that (i.e., cannot overwrite the page) because > the page that the flag is set in might have already been archived. No?
I was imagining that XLP_FIRST_IS_ABORTED_PARTIAL would be set in the "tail end" of a partial record. I.e. if there's a partial record starting in the successfully archived segment A, but the end of the record, in B, has not been written to disk before a crash, we'd set XLP_FIRST_IS_ABORTED_PARTIAL at the end of the valid data in B. Which could not have been archived yet, or we'd not have a partial record. So we should never need to set the flag on an already archived page. Greetings, Andres Freund
