On Tue, Jan 03, 2023 at 02:53:10PM +0530, Bharath Rupireddy wrote: > The proposed patch makes the inherent state change to pg_wal after > failure to read from archive in XLogFileReadAnyTLI() to explicit by > setting currentSource to XLOG_FROM_PG_WAL in the state machine. I > think it doesn't alter the existing state machine or add any new extra > lookups in pg_wal.
Well, did you notice 4d894b41? It introduced this change: - readFile = XLogFileReadAnyTLI(readSegNo, DEBUG2, currentSource); + readFile = XLogFileReadAnyTLI(readSegNo, DEBUG2, + currentSource == XLOG_FROM_ARCHIVE ? XLOG_FROM_ANY : + currentSource); And this patch basically undoes that, meaning that we would basically look at the archives first for all the expected TLIs, but only if no files were found in pg_wal/. The change is subtle, see XLogFileReadAnyTLI(). On HEAD we go through each timeline listed and check both archives and then pg_wal/ after the last source that failed was the archives. The patch does something different: it checks all the timelines for the archives, then all the timelines in pg_wal/ with two separate calls to XLogFileReadAnyTLI(). -- Michael
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