Fix a couple of comments.

diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 1f24fdc5a091e8ddc9bb9e140ef9bf15e792f11f..02d2ded5538e0a7fe44f9d056a4e863e3779c56f 100644 (file)
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -446,10 +446,8 @@ GetOldestXmin(bool allDbs, bool ignoreVacuum)
                                /*
                                 * Also consider the transaction's Xmin, if set.
                                 *
-                                * Note that this Xmin may seem to be guaranteed to be always
-                                * lower than the transaction's Xid, but this is not so because
-                                * there is a time window on which the Xid is already assigned
-                                * but the Xmin has not being calculated yet.
+                                * We must check both Xid and Xmin because there is a window
+                                * where an xact's Xid is set but Xmin isn't yet.
                                 */
                                xid = proc->xmin;
                                if (TransactionIdIsNormal(xid))
@@ -489,7 +487,7 @@ GetOldestXmin(bool allDbs, bool ignoreVacuum)
  *                     older than this are known not running any more.
  *             RecentGlobalXmin: the global xmin (oldest TransactionXmin across all
  *                     running transactions, except those running LAZY VACUUM).  This is
- *                     the same computation done by GetOldestXmin(true, false).
+ *                     the same computation done by GetOldestXmin(true, true).
  *----------
  */
 Snapshot