HBASE-17508 Unify the implementation of small scan and regular scan f…

…or sync client

hbase-client/src/main/java/org/apache/hadoop/hbase/MetaTableAccessor.java

@@ -560,16 +560,12 @@ public static Scan getScanForTableName(Connection connection, TableName tableNam
     // Stop key appends the smallest possible char to the table name
     byte[] stopKey = getTableStopRowForMeta(tableName, QueryType.REGION);
 
-    Scan scan = getMetaScan(connection);
+    Scan scan = getMetaScan(connection, -1);
     scan.setStartRow(startKey);
     scan.setStopRow(stopKey);
     return scan;
   }
 
-  private static Scan getMetaScan(Connection connection) {
-    return getMetaScan(connection, Integer.MAX_VALUE);
-  }
-
   private static Scan getMetaScan(Connection connection, int rowUpperLimit) {
     Scan scan = new Scan();
     int scannerCaching = connection.getConfiguration()
@@ -579,11 +575,11 @@ private static Scan getMetaScan(Connection connection, int rowUpperLimit) {
         HConstants.DEFAULT_USE_META_REPLICAS)) {
       scan.setConsistency(Consistency.TIMELINE);
     }
-    if (rowUpperLimit <= scannerCaching) {
-      scan.setSmall(true);
+    if (rowUpperLimit > 0) {
+      scan.setLimit(rowUpperLimit);
+      scan.setReadType(Scan.ReadType.PREAD);
     }
-    int rows = Math.min(rowUpperLimit, scannerCaching);
-    scan.setCaching(rows);
+    scan.setCaching(scannerCaching);
     return scan;
   }
   /**

hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncNonMetaRegionLocator.java

@@ -377,8 +377,8 @@ private void locateInMeta(TableName tableName, LocateRequest req) {
       metaKey = createRegionName(tableName, req.row, NINES, false);
     }
     conn.getRawTable(META_TABLE_NAME)
-        .scanAll(new Scan().withStartRow(metaKey).setReversed(true).setReadType(ReadType.PREAD)
-            .addFamily(CATALOG_FAMILY).setLimit(1))
+        .scanAll(new Scan().withStartRow(metaKey).setReversed(true).addFamily(CATALOG_FAMILY)
+            .setOneRowLimit())
         .whenComplete((results, error) -> onScanComplete(tableName, req, results, error));
   }