Adjust cutoff points in newly-added sanity tests.

Per recommendation from Andres.

diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 47eef924be099149baf55720407c2f35ee3a922a..79f952c9096a2974bba5f2d5252c8a4c316e4029 100644 (file)
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -745,13 +745,13 @@ vac_update_relstats(Relation relation,
     * which case we don't want to forget the work it already did.  However,
     * if the stored relfrozenxid is "in the future", then it must be corrupt
     * and it seems best to overwrite it with the cutoff we used this time.
-    * See vac_update_datfrozenxid() concerning what we consider to be "in the
-    * future".
+    * This should match vac_update_datfrozenxid() concerning what we consider
+    * to be "in the future".
     */
    if (TransactionIdIsNormal(frozenxid) &&
        pgcform->relfrozenxid != frozenxid &&
        (TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
-        TransactionIdPrecedes(GetOldestXmin(true, true),
+        TransactionIdPrecedes(ReadNewTransactionId(),
                               pgcform->relfrozenxid)))
    {
        pgcform->relfrozenxid = frozenxid;
@@ -762,7 +762,7 @@ vac_update_relstats(Relation relation,
    if (MultiXactIdIsValid(minmulti) &&
        pgcform->relminmxid != minmulti &&
        (MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
-        MultiXactIdPrecedes(GetOldestMultiXactId(), pgcform->relminmxid)))
+        MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
    {
        pgcform->relminmxid = minmulti;
        dirty = true;
@@ -803,8 +803,8 @@ vac_update_datfrozenxid(void)
    SysScanDesc scan;
    HeapTuple   classTup;
    TransactionId newFrozenXid;
-   TransactionId lastSaneFrozenXid;
    MultiXactId newMinMulti;
+   TransactionId lastSaneFrozenXid;
    MultiXactId lastSaneMinMulti;
    bool        bogus = false;
    bool        dirty = false;
@@ -815,13 +815,21 @@ vac_update_datfrozenxid(void)
     * committed pg_class entries for new tables; see AddNewRelationTuple().
     * So we cannot produce a wrong minimum by starting with this.
     */
-   newFrozenXid = lastSaneFrozenXid = GetOldestXmin(true, true);
+   newFrozenXid = GetOldestXmin(true, true);
 
    /*
     * Similarly, initialize the MultiXact "min" with the value that would be
     * used on pg_class for new tables.  See AddNewRelationTuple().
     */
-   newMinMulti = lastSaneMinMulti = GetOldestMultiXactId();
+   newMinMulti = GetOldestMultiXactId();
+
+   /*
+    * Identify the latest relfrozenxid and relminmxid values that we could
+    * validly see during the scan.  These are conservative values, but it's
+    * not really worth trying to be more exact.
+    */
+   lastSaneFrozenXid = ReadNewTransactionId();
+   lastSaneMinMulti = ReadNextMultiXactId();
 
    /*
     * We must seqscan pg_class to find the minimum Xid, because there is no