diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index 360b26e..9883c36 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -951,9 +951,15 @@ summarize_range(IndexInfo *indexInfo, BrinBuildState *state, Relation heapRel,
 	 * Execute the partial heap scan covering the heap blocks in the specified
 	 * page range, summarizing the heap tuples in it.  This scan stops just
 	 * short of brinbuildCallback creating the new index entry.
+	 *
+	 * Note that it is critical we use the "latest snapshot" mode of
+	 * IndexBuildHeapRangeScan here: otherwise, in transaction-snapshot
+	 * isolation mode the snapshot used would be earlier than the insertion of
+	 * the placeholder tuple, leading to values inserted concurrently not
+	 * being considered in the summary info of the block range.
 	 */
 	state->bs_currRangeStart = heapBlk;
-	IndexBuildHeapRangeScan(heapRel, state->bs_irel, indexInfo, false,
+	IndexBuildHeapRangeScan(heapRel, state->bs_irel, indexInfo, false, true,
 							heapBlk, state->bs_pagesPerRange,
 							brinbuildCallback, (void *) state);
 
@@ -1066,28 +1072,10 @@ brinsummarize(Relation index, Relation heapRel, double *numSummarized,
 				 * additional precautions to avoid losing the additional
 				 * tuples; see comments in summarize_range.  Set the
 				 * concurrent flag, which causes IndexBuildHeapRangeScan to
-				 * use a snapshot other than SnapshotAny, and silences
+				 * use LatestSnapshot rather than SnapshotAny, and silences
 				 * warnings emitted there.
 				 */
 				indexInfo->ii_Concurrent = true;
-
-				/*
-				 * If using transaction-snapshot mode, it would be possible
-				 * for another transaction to insert a tuple that's not
-				 * visible to our snapshot if we have already acquired one,
-				 * when in snapshot-isolation mode; therefore, disallow this
-				 * from running in such a transaction unless a snapshot hasn't
-				 * been acquired yet.
-				 *
-				 * This code is called by VACUUM and
-				 * brin_summarize_new_values. Have the error message mention
-				 * the latter because VACUUM cannot run in a transaction and
-				 * thus cannot cause this issue.
-				 */
-				if (IsolationUsesXactSnapshot() && FirstSnapshotSet)
-					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
-							 errmsg("brin_summarize_new_values() cannot run in a transaction that has already obtained a snapshot")));
 			}
 			summarize_range(indexInfo, state, heapRel, heapBlk);
 
@@ -1111,7 +1099,10 @@ brinsummarize(Relation index, Relation heapRel, double *numSummarized,
 	/* free resources */
 	brinRevmapTerminate(revmap);
 	if (state)
+	{
 		terminate_brin_buildstate(state);
+		pfree(indexInfo);
+	}
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 69f35c9..2390e36 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -2161,6 +2161,7 @@ IndexBuildHeapScan(Relation heapRelation,
 {
 	return IndexBuildHeapRangeScan(heapRelation, indexRelation,
 								   indexInfo, allow_sync,
+								   false,
 								   0, InvalidBlockNumber,
 								   callback, callback_state);
 }
@@ -2170,12 +2171,17 @@ IndexBuildHeapScan(Relation heapRelation,
  * number of blocks are scanned.  Scan to end-of-rel can be signalled by
  * passing InvalidBlockNumber as numblocks.  Note that restricting the range
  * to scan cannot be done when requesting syncscan.
+ *
+ * If use_latest_snapshot, the snapshot used is not the transaction snapshot,
+ * but obtained using GetLatestSnapshot().  (Note this only affects scans
+ * marked ii_Concurrent).
  */
 double
 IndexBuildHeapRangeScan(Relation heapRelation,
 						Relation indexRelation,
 						IndexInfo *indexInfo,
 						bool allow_sync,
+						bool use_latest_snapshot,
 						BlockNumber start_blockno,
 						BlockNumber numblocks,
 						IndexBuildCallback callback,
@@ -2234,7 +2240,9 @@ IndexBuildHeapRangeScan(Relation heapRelation,
 	 */
 	if (IsBootstrapProcessingMode() || indexInfo->ii_Concurrent)
 	{
-		snapshot = RegisterSnapshot(GetTransactionSnapshot());
+		snapshot = use_latest_snapshot ?
+			GetLatestSnapshot() : GetTransactionSnapshot();
+		snapshot = RegisterSnapshot(snapshot);
 		OldestXmin = InvalidTransactionId;		/* not used */
 	}
 	else
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 8b3b28d..4ad5ac3 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -105,6 +105,7 @@ extern double IndexBuildHeapRangeScan(Relation heapRelation,
 						Relation indexRelation,
 						IndexInfo *indexInfo,
 						bool allow_sync,
+						bool use_latest_snapshot,
 						BlockNumber start_blockno,
 						BlockNumber end_blockno,
 						IndexBuildCallback callback,