Hi Noah, On Sat, Apr 04, 2020 at 08:40:43PM +0000, Noah Misch wrote: > Skip WAL for new relfilenodes, under wal_level=minimal. > > Until now, only selected bulk operations (e.g. COPY) did this. If a > given relfilenode received both a WAL-skipping COPY and a WAL-logged > operation (e.g. INSERT), recovery could lose tuples from the COPY. See > src/backend/access/transam/README section "Skipping WAL for New > RelFileNode" for the new coding rules. Maintainers of table access > methods should examine that section. > > To maintain data durability, just before commit, we choose between an > fsync of the relfilenode and copying its contents to WAL. A new GUC, > wal_skip_threshold, guides that choice. If this change slows a workload > that creates small, permanent relfilenodes under wal_level=minimal, try > adjusting wal_skip_threshold. Users setting a timeout on COMMIT may > need to adjust that timeout, and log_min_duration_statement analysis > will reflect time consumption moving to COMMIT from commands like COPY.
+ /* + * Records other than SWITCH_WAL must have content. We use an integer 0 to + * follow the restriction. + */ This commit has added the following comment, but I guess you meant XLOG_SWITCH instead? -- Michael
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