GG-23230 Several open iterators by lazy SQL query can lead to assertion error.

Author: ygerzhedovich

modules/indexing/src/main/java/org/apache/ignite/internal/processors/query/h2/IgniteH2Indexing.java

@@ -1672,6 +1672,14 @@ private ParsingResult parseAndSplit(String schemaName, SqlFieldsQuery qry, int f
             return new ParsingResult(prepared, newQry, remainingSql, twoStepQry, cachedQryKey, meta);
         }
 
+
+        // The part executed in user thread. In case user open few iterators ThreadLocal context will be invalid.
+        // To prevent it we keep old context and restore after.
+        GridH2QueryContext oldCtx = GridH2QueryContext.get();
+
+        if(oldCtx != null)
+            GridH2QueryContext.clearThreadLocal();
+
         try {
             GridH2QueryContext.set(new GridH2QueryContext(locNodeId, locNodeId, 0, PREPARE)
                 .distributedJoinMode(distributedJoinMode(qry.isLocal(), qry.isDistributedJoins())));
@@ -1693,6 +1701,10 @@ private ParsingResult parseAndSplit(String schemaName, SqlFieldsQuery qry, int f
         }
         finally {
             GridH2QueryContext.clearThreadLocal();
+
+            if(oldCtx != null)
+                GridH2QueryContext.set(oldCtx);
+
         }
     }
 

modules/indexing/src/test/java/org/apache/ignite/internal/processors/query/LocalQueryLazyTest.java

@@ -112,6 +112,36 @@ public void testDuplicates() throws Exception {
         assertEquals(KEY_CNT, r0 + r1);
     }
 
+    /** */
+    public void testParallelIterator() throws Exception {
+        IgniteEx g1 = startGrid(0);
+
+        awaitPartitionMapExchange(true, true, null);
+
+        Iterator<List<?>> cursorIter0 = sql(g1, "SELECT * FROM test").iterator();
+        Iterator<List<?>> cursorIter1 = distributedSql(g1, "SELECT * FROM test").iterator();
+
+        int r0 = 0;
+        int r1 = 0;
+
+        for (int i =0; i<KEY_CNT; i++) {
+            if (cursorIter0.hasNext()) {
+                r0++;
+
+                cursorIter0.next();
+            }
+
+            if (cursorIter1.hasNext()) {
+                r1++;
+
+                cursorIter1.next();
+            }
+        }
+
+        assertTrue(r0 < KEY_CNT);
+        assertEquals(KEY_CNT, r1);
+    }
+
     /**
      * @param sql SQL query.
      * @param args Query parameters.
@@ -134,4 +164,17 @@ private FieldsQueryCursor<List<?>> sql(IgniteEx ign, String sql, Object ... args
             .setSchema("TEST")
             .setArgs(args), false);
     }
+
+    /**
+     * @param ign Node.
+     * @param sql SQL query.
+     * @param args Query parameters.
+     * @return Results cursor.
+     */
+    private FieldsQueryCursor<List<?>> distributedSql(IgniteEx ign, String sql, Object ... args) {
+        return ign.context().query().querySqlFields(new SqlFieldsQuery(sql)
+            .setLazy(true)
+            .setSchema("TEST")
+            .setArgs(args), false);
+    }
 }