Filter expression with OR isnull(x) should be pushed down

integ-test/src/test/java/org/opensearch/sql/calcite/remote/CalciteExplainIT.java

@@ -94,6 +94,51 @@ public void supportPartialPushDown_NoPushIfAllFailed() throws IOException {
     assertJsonEqualsIgnoreId(expected, result);
   }
 
+  // Only for Calcite
+  @Test
+  public void testExplainIsEmpty() throws IOException {
+    // cannot pushdown
+    String expected = loadExpectedPlan("explain_isempty.json");
+    assertJsonEqualsIgnoreId(
+        expected,
+        explainQueryToString(
+            "source=opensearch-sql_test_index_account | where isempty(firstname)"));
+  }
+
+  // Only for Calcite
+  @Test
+  public void testExplainIsBlank() throws IOException {
+    // cannot pushdown
+    String expected = loadExpectedPlan("explain_isblank.json");
+    assertJsonEqualsIgnoreId(
+        expected,
+        explainQueryToString(
+            "source=opensearch-sql_test_index_account | where isblank(firstname)"));
+  }
+
+  // Only for Calcite
+  @Test
+  public void testExplainIsEmptyOrOthers() throws IOException {
+    // cannot pushdown
+    String expected = loadExpectedPlan("explain_isempty_or_others.json");
+    assertJsonEqualsIgnoreId(
+        expected,
+        explainQueryToString(
+            "source=opensearch-sql_test_index_account | where gender = 'M' or isempty(firstname) or"
+                + " isnull(firstname)"));
+  }
+
+  // Only for Calcite
+  @Test
+  public void testExplainIsNullOrOthers() throws IOException {
+    // pushdown should work
+    String expected = loadExpectedPlan("explain_isnull_or_others.json");
+    assertJsonEqualsIgnoreId(
+        expected,
+        explainQueryToString(
+            "source=opensearch-sql_test_index_account | where isnull(firstname) or gender = 'M'"));
+  }
+
   @Test
   public void supportPartialPushDownScript() throws IOException {
     Assume.assumeTrue("This test is only for push down enabled", isPushdownEnabled());

integ-test/src/test/resources/expectedOutput/calcite/explain_isblank.json

@@ -0,0 +1,6 @@
+{
+  "calcite": {
+    "logical": "LogicalSystemLimit(fetch=[10000], type=[QUERY_SIZE_LIMIT])\n  LogicalProject(account_number=[$0], firstname=[$1], address=[$2], balance=[$3], gender=[$4], city=[$5], employer=[$6], state=[$7], age=[$8], email=[$9], lastname=[$10])\n    LogicalFilter(condition=[OR(IS NULL($1), IS EMPTY(TRIM(FLAG(BOTH), ' ', $1)))])\n      CalciteLogicalIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n",
+    "physical": "EnumerableLimit(fetch=[10000])\n  EnumerableCalc(expr#0..10=[{inputs}], expr#11=[IS NULL($t1)], expr#12=[FLAG(BOTH)], expr#13=[' '], expr#14=[TRIM($t12, $t13, $t1)], expr#15=[IS EMPTY($t14)], expr#16=[OR($t11, $t15)], proj#0..10=[{exprs}], $condition=[$t16])\n    CalciteEnumerableIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]], PushDownContext=[[PROJECT->[account_number, firstname, address, balance, gender, city, employer, state, age, email, lastname]], OpenSearchRequestBuilder(sourceBuilder={\"from\":0,\"timeout\":\"1m\",\"_source\":{\"includes\":[\"account_number\",\"firstname\",\"address\",\"balance\",\"gender\",\"city\",\"employer\",\"state\",\"age\",\"email\",\"lastname\"],\"excludes\":[]}}, requestedTotalSize=2147483647, pageSize=null, startFrom=0)])\n"
+  }
+}

integ-test/src/test/resources/expectedOutput/calcite/explain_isempty.json

@@ -0,0 +1,6 @@
+{
+  "calcite": {
+    "logical": "LogicalSystemLimit(fetch=[10000], type=[QUERY_SIZE_LIMIT])\n  LogicalProject(account_number=[$0], firstname=[$1], address=[$2], balance=[$3], gender=[$4], city=[$5], employer=[$6], state=[$7], age=[$8], email=[$9], lastname=[$10])\n    LogicalFilter(condition=[OR(IS NULL($1), IS EMPTY($1))])\n      CalciteLogicalIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n",
+    "physical": "EnumerableLimit(fetch=[10000])\n  EnumerableCalc(expr#0..10=[{inputs}], expr#11=[IS NULL($t1)], expr#12=[IS EMPTY($t1)], expr#13=[OR($t11, $t12)], proj#0..10=[{exprs}], $condition=[$t13])\n    CalciteEnumerableIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]], PushDownContext=[[PROJECT->[account_number, firstname, address, balance, gender, city, employer, state, age, email, lastname]], OpenSearchRequestBuilder(sourceBuilder={\"from\":0,\"timeout\":\"1m\",\"_source\":{\"includes\":[\"account_number\",\"firstname\",\"address\",\"balance\",\"gender\",\"city\",\"employer\",\"state\",\"age\",\"email\",\"lastname\"],\"excludes\":[]}}, requestedTotalSize=2147483647, pageSize=null, startFrom=0)])\n"
+  }
+}

integ-test/src/test/resources/expectedOutput/calcite/explain_isempty_or_others.json

@@ -0,0 +1,6 @@
+{
+  "calcite": {
+    "logical": "LogicalSystemLimit(fetch=[10000], type=[QUERY_SIZE_LIMIT])\n  LogicalProject(account_number=[$0], firstname=[$1], address=[$2], balance=[$3], gender=[$4], city=[$5], employer=[$6], state=[$7], age=[$8], email=[$9], lastname=[$10])\n    LogicalFilter(condition=[OR(=($4, 'M'), IS NULL($1), IS EMPTY($1))])\n      CalciteLogicalIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n",
+    "physical": "EnumerableLimit(fetch=[10000])\n  EnumerableCalc(expr#0..10=[{inputs}], expr#11=[IS NULL($t1)], expr#12=['M'], expr#13=[=($t4, $t12)], expr#14=[IS EMPTY($t1)], expr#15=[OR($t11, $t13, $t14)], proj#0..10=[{exprs}], $condition=[$t15])\n    CalciteEnumerableIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]], PushDownContext=[[PROJECT->[account_number, firstname, address, balance, gender, city, employer, state, age, email, lastname]], OpenSearchRequestBuilder(sourceBuilder={\"from\":0,\"timeout\":\"1m\",\"_source\":{\"includes\":[\"account_number\",\"firstname\",\"address\",\"balance\",\"gender\",\"city\",\"employer\",\"state\",\"age\",\"email\",\"lastname\"],\"excludes\":[]}}, requestedTotalSize=2147483647, pageSize=null, startFrom=0)])\n"
+  }
+}

integ-test/src/test/resources/expectedOutput/calcite/explain_isnull_or_others.json

@@ -0,0 +1,6 @@
+{
+  "calcite": {
+    "logical": "LogicalSystemLimit(fetch=[10000], type=[QUERY_SIZE_LIMIT])\n  LogicalProject(account_number=[$0], firstname=[$1], address=[$2], balance=[$3], gender=[$4], city=[$5], employer=[$6], state=[$7], age=[$8], email=[$9], lastname=[$10])\n    LogicalFilter(condition=[OR(IS NULL($1), =($4, 'M'))])\n      CalciteLogicalIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n",
+    "physical": "CalciteEnumerableIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]], PushDownContext=[[PROJECT->[account_number, firstname, address, balance, gender, city, employer, state, age, email, lastname], FILTER->OR(IS NULL($1), =($4, 'M')), LIMIT->10000], OpenSearchRequestBuilder(sourceBuilder={\"from\":0,\"size\":10000,\"timeout\":\"1m\",\"query\":{\"bool\":{\"should\":[{\"bool\":{\"must_not\":[{\"exists\":{\"field\":\"firstname\",\"boost\":1.0}}],\"adjust_pure_negative\":true,\"boost\":1.0}},{\"term\":{\"gender.keyword\":{\"value\":\"M\",\"boost\":1.0}}}],\"adjust_pure_negative\":true,\"boost\":1.0}},\"_source\":{\"includes\":[\"account_number\",\"firstname\",\"address\",\"balance\",\"gender\",\"city\",\"employer\",\"state\",\"age\",\"email\",\"lastname\"],\"excludes\":[]},\"sort\":[{\"_doc\":{\"order\":\"asc\"}}]}, requestedTotalSize=10000, pageSize=null, startFrom=0)])\n"
+  }
+}

integ-test/src/test/resources/expectedOutput/calcite_no_pushdown/explain_isblank.json

@@ -0,0 +1,6 @@
+{
+  "calcite": {
+    "logical": "LogicalSystemLimit(fetch=[10000], type=[QUERY_SIZE_LIMIT])\n  LogicalProject(account_number=[$0], firstname=[$1], address=[$2], balance=[$3], gender=[$4], city=[$5], employer=[$6], state=[$7], age=[$8], email=[$9], lastname=[$10])\n    LogicalFilter(condition=[OR(IS NULL($1), IS EMPTY(TRIM(FLAG(BOTH), ' ', $1)))])\n      CalciteLogicalIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n",
+    "physical": "EnumerableLimit(fetch=[10000])\n  EnumerableCalc(expr#0..16=[{inputs}], expr#17=[IS NULL($t1)], expr#18=[FLAG(BOTH)], expr#19=[' '], expr#20=[TRIM($t18, $t19, $t1)], expr#21=[IS EMPTY($t20)], expr#22=[OR($t17, $t21)], proj#0..10=[{exprs}], $condition=[$t22])\n    CalciteEnumerableIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n"
+  }
+}

integ-test/src/test/resources/expectedOutput/calcite_no_pushdown/explain_isempty.json

@@ -0,0 +1,6 @@
+{
+  "calcite": {
+    "logical": "LogicalSystemLimit(fetch=[10000], type=[QUERY_SIZE_LIMIT])\n  LogicalProject(account_number=[$0], firstname=[$1], address=[$2], balance=[$3], gender=[$4], city=[$5], employer=[$6], state=[$7], age=[$8], email=[$9], lastname=[$10])\n    LogicalFilter(condition=[OR(IS NULL($1), IS EMPTY($1))])\n      CalciteLogicalIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n",
+    "physical": "EnumerableLimit(fetch=[10000])\n  EnumerableCalc(expr#0..16=[{inputs}], expr#17=[IS NULL($t1)], expr#18=[IS EMPTY($t1)], expr#19=[OR($t17, $t18)], proj#0..10=[{exprs}], $condition=[$t19])\n    CalciteEnumerableIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n"
+  }
+}

integ-test/src/test/resources/expectedOutput/calcite_no_pushdown/explain_isempty_or_others.json

@@ -0,0 +1,6 @@
+{
+  "calcite": {
+    "logical": "LogicalSystemLimit(fetch=[10000], type=[QUERY_SIZE_LIMIT])\n  LogicalProject(account_number=[$0], firstname=[$1], address=[$2], balance=[$3], gender=[$4], city=[$5], employer=[$6], state=[$7], age=[$8], email=[$9], lastname=[$10])\n    LogicalFilter(condition=[OR(=($4, 'M'), IS NULL($1), IS EMPTY($1))])\n      CalciteLogicalIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n",
+    "physical": "EnumerableLimit(fetch=[10000])\n  EnumerableCalc(expr#0..16=[{inputs}], expr#17=[IS NULL($t1)], expr#18=['M'], expr#19=[=($t4, $t18)], expr#20=[IS EMPTY($t1)], expr#21=[OR($t17, $t19, $t20)], proj#0..10=[{exprs}], $condition=[$t21])\n    CalciteEnumerableIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n"
+  }
+}

integ-test/src/test/resources/expectedOutput/calcite_no_pushdown/explain_isnull_or_others.json

@@ -0,0 +1,6 @@
+{
+  "calcite": {
+    "logical": "LogicalSystemLimit(fetch=[10000], type=[QUERY_SIZE_LIMIT])\n  LogicalProject(account_number=[$0], firstname=[$1], address=[$2], balance=[$3], gender=[$4], city=[$5], employer=[$6], state=[$7], age=[$8], email=[$9], lastname=[$10])\n    LogicalFilter(condition=[OR(IS NULL($1), =($4, 'M'))])\n      CalciteLogicalIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n",
+    "physical": "EnumerableLimit(fetch=[10000])\n  EnumerableCalc(expr#0..16=[{inputs}], expr#17=[IS NULL($t1)], expr#18=['M'], expr#19=[=($t4, $t18)], expr#20=[OR($t17, $t19)], proj#0..10=[{exprs}], $condition=[$t20])\n    CalciteEnumerableIndexScan(table=[[OpenSearch, opensearch-sql_test_index_account]])\n"
+  }
+}

opensearch/src/main/java/org/opensearch/sql/opensearch/request/PredicateAnalyzer.java

@@ -634,13 +634,20 @@ private static QueryExpression constructQueryExpressionForSearch(
       }
     }
 
+    private boolean containIsEmptyFunction(RexCall call) {
+      return call.getKind() == SqlKind.OR
+          && call.getOperands().stream().anyMatch(o -> o.getKind() == SqlKind.IS_NULL)
+          && call.getOperands().stream()
+              .anyMatch(
+                  o ->
+                      o.getKind() == SqlKind.OTHER
+                          && ((RexCall) o).getOperator().equals(SqlStdOperatorTable.IS_EMPTY));
+    }
+
     private QueryExpression andOr(RexCall call) {
       // For function isEmpty and isBlank, we implement them via expression `isNull or {@function}`,
       // Unlike `OR` in Java, `SHOULD` in DSL will evaluate both branches and lead to NPE.
-      if (call.getKind() == SqlKind.OR
-          && call.getOperands().size() == 2
-          && (call.getOperands().get(0).getKind() == SqlKind.IS_NULL
-              || call.getOperands().get(1).getKind() == SqlKind.IS_NULL)) {
+      if (containIsEmptyFunction(call)) {
         throw new UnsupportedScriptException(
             "DSL will evaluate both branches of OR with isNUll, prevent push-down to avoid NPE");
       }