Remove obsolete commentary.

Since we got rid of non-MVCC catalog scans, the fourth reason given for
using a non-transactional update in index_update_stats() is obsolete.
The other three are still good, so we're not going to change the code,
but fix the comment.

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index a5a204eb40b20185a5b465abaf13ade1f5de460a..f691dd30c19412110157e0498bbd4131dc2890b5 100644 (file)
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1783,14 +1783,6 @@ index_update_stats(Relation rel,
         * trying to change the pg_class row to the same thing, so it doesn't
         * matter which goes first).
         *
-        * 4. Even with just a single CREATE INDEX, there's a risk factor because
-        * someone else might be trying to open the rel while we commit, and this
-        * creates a race condition as to whether he will see both or neither of
-        * the pg_class row versions as valid.  Again, a non-transactional update
-        * avoids the risk.  It is indeterminate which state of the row the other
-        * process will see, but it doesn't matter (if he's only taking
-        * AccessShareLock, then it's not critical that he see relhasindex true).
-        *
         * It is safe to use a non-transactional update even though our
         * transaction could still fail before committing.  Setting relhasindex
         * true is safe even if there are no indexes (VACUUM will eventually fix