On LWLockDisown():
+/*
+ * Stop treating lock as held by current backend.
+ *
+ * After calling this function it's the callers responsibility to ensure that
+ * the lock gets released, even in case of an error. This only is desirable if
+ * the lock is going to be released in a different process than the process
+ * that acquired it.
+ *
+ * Returns the mode in which the lock was held by the current backend.
Returning the lock mode feels a bit ad hoc..
+ * NB: This will leave lock->owner pointing to the current backend (if
+ * LOCK_DEBUG is set). We could add a separate flag indicating that, but it
+ * doesn't really seem worth it.
Hmm. I won't insist, but I feel it probably would be worth it. This is
only in LOCK_DEBUG mode so there's no performance penalty in non-debug
builds, and when you do compile with LOCK_DEBUG you probably appreciate
any extra information.
+ * NB: This does not call RESUME_INTERRUPTS(), but leaves that responsibility
+ * of the caller.
+ */
That feels weird. The only caller outside lwlock.c does call
RESUME_INTERRUPTS() immediately.
Perhaps it'd make for a better external interface if LWLockDisown() did
call RESUME_INTERRUPTS(), and there was a separate internal version that
didn't. And it might make more sense for the external version to return
'void' while we're at it. Returning a value that the caller ignores is
harmless, of course, but it feels a bit weird. It makes you wonder what
you're supposed to do with it.
+ {
+ {"io_method", PGC_POSTMASTER, RESOURCES_MEM,
+ gettext_noop("Selects the method of asynchronous I/O to
use."),
+ NULL
+ },
+ &io_method,
+ DEFAULT_IO_METHOD, io_method_options,
+ NULL, assign_io_method, NULL
+ },
+
The description is a bit funny because synchronous I/O is one of the
possible methods.
--
Heikki Linnakangas
Neon (https://neon.tech)
