diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index de491ea0c4b..27ba27f4162 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -701,6 +701,10 @@ SnapBuildProcessNewCid(SnapBuild *builder, TransactionId xid,
 	 */
 	ReorderBufferXidSetCatalogChanges(builder->reorder, xid, lsn);
 
+	/* EXPERIMENT: which catalog does this change touch? */
+	elog(LOG, "NEWCID xid=%u top=%u rel=%u",
+		 xid, xlrec->top_xid, xlrec->target_locator.relNumber);
+
 	ReorderBufferAddNewTupleCids(builder->reorder, xlrec->top_xid, lsn,
 								 xlrec->target_locator, xlrec->target_tid,
 								 xlrec->cmin, xlrec->cmax,
@@ -968,6 +972,17 @@ SnapBuildCommitTxn(SnapBuild *builder, XLogRecPtr lsn, TransactionId xid,
 		return;
 	}
 
+	/* EXPERIMENT: does every catalog-changing xact carry invalidations? */
+	elog(LOG, "CATCHK state=%d xid=%u sub=0 rb=%d invals=%d",
+		 builder->state, xid,
+		 ReorderBufferXidHasCatalogChanges(builder->reorder, xid),
+		 (xinfo & XACT_XINFO_HAS_INVALS) != 0);
+	for (int i = 0; i < nsubxacts; i++)
+		elog(LOG, "CATCHK state=%d xid=%u sub=1 rb=%d invals=%d",
+			 builder->state, subxacts[i],
+			 ReorderBufferXidHasCatalogChanges(builder->reorder, subxacts[i]),
+			 (xinfo & XACT_XINFO_HAS_INVALS) != 0);
+
 	if (builder->state < SNAPBUILD_CONSISTENT)
 	{
 		/* ensure that only commits after this are getting replayed */