amcheck: Remove duplicate XID/MXID bounds checks.

Commit 3b6c1259f9ca8e21860aaf24ec6735a8e5598ea0 resulted in the same
xmin and xmax bounds checking being performed in both check_tuple()
and check_tuple_visibility(). Remove the duplication.

While at it, adjust some code comments that were overlooked in that
commit.

Mark Dilger

Discussion: http://postgr.es/m/AC5479E4-6321-473D-AC92-5EC36299FBC2@enterprisedb.com

diff --git a/contrib/amcheck/verify_heapam.c b/contrib/amcheck/verify_heapam.c
index 11ace483d04088802aa4af806d5963025b1ec533..1d769035f1349e127b91caf23584d7077464b3f6 100644 (file)
--- a/contrib/amcheck/verify_heapam.c
+++ b/contrib/amcheck/verify_heapam.c
@@ -1390,136 +1390,18 @@ check_tuple_attribute(HeapCheckContext *ctx)
 static void
 check_tuple(HeapCheckContext *ctx)
 {
-       TransactionId xmin;
-       TransactionId xmax;
-       bool            fatal = false;
-       uint16          infomask = ctx->tuphdr->t_infomask;
-
-       /* If xmin is normal, it should be within valid range */
-       xmin = HeapTupleHeaderGetXmin(ctx->tuphdr);
-       switch (get_xid_status(xmin, ctx, NULL))
-       {
-               case XID_INVALID:
-               case XID_BOUNDS_OK:
-                       break;
-               case XID_IN_FUTURE:
-                       report_corruption(ctx,
-                                                         psprintf("xmin %u equals or exceeds next valid transaction ID %u:%u",
-                                                                          xmin,
-                                                                          EpochFromFullTransactionId(ctx->next_fxid),
-                                                                          XidFromFullTransactionId(ctx->next_fxid)));
-                       fatal = true;
-                       break;
-               case XID_PRECEDES_CLUSTERMIN:
-                       report_corruption(ctx,
-                                                         psprintf("xmin %u precedes oldest valid transaction ID %u:%u",
-                                                                          xmin,
-                                                                          EpochFromFullTransactionId(ctx->oldest_fxid),
-                                                                          XidFromFullTransactionId(ctx->oldest_fxid)));
-                       fatal = true;
-                       break;
-               case XID_PRECEDES_RELMIN:
-                       report_corruption(ctx,
-                                                         psprintf("xmin %u precedes relation freeze threshold %u:%u",
-                                                                          xmin,
-                                                                          EpochFromFullTransactionId(ctx->relfrozenfxid),
-                                                                          XidFromFullTransactionId(ctx->relfrozenfxid)));
-                       fatal = true;
-                       break;
-       }
-
-       xmax = HeapTupleHeaderGetRawXmax(ctx->tuphdr);
-
-       if (infomask & HEAP_XMAX_IS_MULTI)
-       {
-               /* xmax is a multixact, so it should be within valid MXID range */
-               switch (check_mxid_valid_in_rel(xmax, ctx))
-               {
-                       case XID_INVALID:
-                               report_corruption(ctx,
-                                                                 pstrdup("multitransaction ID is invalid"));
-                               fatal = true;
-                               break;
-                       case XID_PRECEDES_RELMIN:
-                               report_corruption(ctx,
-                                                                 psprintf("multitransaction ID %u precedes relation minimum multitransaction ID threshold %u",
-                                                                                  xmax, ctx->relminmxid));
-                               fatal = true;
-                               break;
-                       case XID_PRECEDES_CLUSTERMIN:
-                               report_corruption(ctx,
-                                                                 psprintf("multitransaction ID %u precedes oldest valid multitransaction ID threshold %u",
-                                                                                  xmax, ctx->oldest_mxact));
-                               fatal = true;
-                               break;
-                       case XID_IN_FUTURE:
-                               report_corruption(ctx,
-                                                                 psprintf("multitransaction ID %u equals or exceeds next valid multitransaction ID %u",
-                                                                                  xmax,
-                                                                                  ctx->next_mxact));
-                               fatal = true;
-                               break;
-                       case XID_BOUNDS_OK:
-                               break;
-               }
-       }
-       else
-       {
-               /*
-                * xmax is not a multixact and is normal, so it should be within the
-                * valid XID range.
-                */
-               switch (get_xid_status(xmax, ctx, NULL))
-               {
-                       case XID_INVALID:
-                       case XID_BOUNDS_OK:
-                               break;
-                       case XID_IN_FUTURE:
-                               report_corruption(ctx,
-                                                                 psprintf("xmax %u equals or exceeds next valid transaction ID %u:%u",
-                                                                                  xmax,
-                                                                                  EpochFromFullTransactionId(ctx->next_fxid),
-                                                                                  XidFromFullTransactionId(ctx->next_fxid)));
-                               fatal = true;
-                               break;
-                       case XID_PRECEDES_CLUSTERMIN:
-                               report_corruption(ctx,
-                                                                 psprintf("xmax %u precedes oldest valid transaction ID %u:%u",
-                                                                                  xmax,
-                                                                                  EpochFromFullTransactionId(ctx->oldest_fxid),
-                                                                                  XidFromFullTransactionId(ctx->oldest_fxid)));
-                               fatal = true;
-                               break;
-                       case XID_PRECEDES_RELMIN:
-                               report_corruption(ctx,
-                                                                 psprintf("xmax %u precedes relation freeze threshold %u:%u",
-                                                                                  xmax,
-                                                                                  EpochFromFullTransactionId(ctx->relfrozenfxid),
-                                                                                  XidFromFullTransactionId(ctx->relfrozenfxid)));
-                               fatal = true;
-               }
-       }
-
        /*
-        * Cannot process tuple data if tuple header was corrupt, as the offsets
-        * within the page cannot be trusted, leaving too much risk of reading
-        * garbage if we continue.
-        *
-        * We also cannot process the tuple if the xmin or xmax were invalid
-        * relative to relfrozenxid or relminmxid, as clog entries for the xids
-        * may already be gone.
+        * Check various forms of tuple header corruption, and if the header is too
+        * corrupt, do not continue with other checks.
         */
-       if (fatal)
+       if (!check_tuple_header(ctx))
                return;
 
        /*
-        * Check various forms of tuple header corruption.  If the header is too
-        * corrupt to continue checking, or if the tuple is not visible to anyone,
-        * we cannot continue with other checks.
+        * Check tuple visibility.  If the inserting transaction aborted, we
+        * cannot assume our relation description matches the tuple structure, and
+        * therefore cannot check it.
         */
-       if (!check_tuple_header(ctx))
-               return;
-
        if (!check_tuple_visibility(ctx))
                return;