IN(..): when combining and IN(..) condition with a condition that didn't use an…

IN(..): when combining and IN(..) condition with a condition that didn't use an index, the result could contain duplicate rows.

h2/src/docsrc/html/changelog.html

@@ -19,7 +19,9 @@ Change Log
 
 <h2>Next Version (unreleased)</h2>
 <ul><li>EXPLAIN: The query plan now contains ".tableScan" if a table scan is used.
-</li><li>The index was not used if there were multiple IN(..) conditions.
+</li><li>IN(..): when combining and IN(..) condition with a condition that didn't use an index,
+    the result could contain duplicate rows.
+</li><li>IN(..): the index was not used if there were multiple IN(..) conditions.
 </li><li>For foreign key constraints, the metadata column
     INFORMATION_SCHEMA.INDEXES.CONSTRAINT_NAME was not set for non-unique indexes.
 </li><li>PostgreSQL compatibility: when using the following exception was thrown:

h2/src/main/org/h2/index/IndexCondition.java

@@ -20,6 +20,7 @@ import org.h2.expression.ExpressionVisitor;
 import org.h2.message.DbException;
 import org.h2.result.ResultInterface;
 import org.h2.table.Column;
+import org.h2.table.Table;
 import org.h2.util.StatementBuilder;
 import org.h2.value.CompareMode;
 import org.h2.value.Value;
@@ -219,28 +220,16 @@ public class IndexCondition {
         case Comparison.IN_LIST:
         case Comparison.IN_QUERY:
             if (indexConditions.size() > 1) {
-                // IN(..) can not be combined with other conditions.
-                // If there are other conditions (except for other
-                // IN_ conditions), don't use the index on IN(..)
-                // otherwise the query returns the wrong result.
-                boolean beforeThis = true;
-                for (IndexCondition c : indexConditions) {
-                    if (c == this) {
-                        beforeThis = false;
-                        continue;
-                    }
-                    if (c.isEvaluatable()) {
-                        if (beforeThis) {
-                            // If there are only multiple IN_ conditions,
-                            // only the first one can be used
-                            return 0;
-                        }
-                        if (!c.isIn()) {
-                            // If there are other (non-IN_) conditions,
-                            // this one can't be used
-                            return 0;
-                        }
-                    }
+                if (!column.getTable().getTableType().equals(Table.TABLE)) {
+                    // if combined with other conditions,
+                    // IN(..) can only be used for regular tables
+                    // test case:
+                    // create table test(a int, b int, primary key(id, name));
+                    // create unique index c on test(b, a);
+                    // insert into test values(1, 10), (2, 20);
+                    // select * from (select * from test)
+                    // where a=1 and b in(10, 20);
+                    return 0;
                 }
             }
             return EQUALITY;
@@ -264,16 +253,6 @@ public class IndexCondition {
         return compareType == Comparison.FALSE;
     }
 
-    private boolean isIn() {
-        switch (compareType) {
-        case Comparison.IN_LIST:
-        case Comparison.IN_QUERY:
-            return true;
-        default:
-            return false;
-        }
-    }
-
     /**
      * Check if this index condition is of the type column larger or equal to
      * value.

h2/src/main/org/h2/index/PageDataIndex.java

@@ -249,7 +249,10 @@ public class PageDataIndex extends PageIndex {
     }
 
     public Cursor find(Session session, SearchRow first, SearchRow last) {
-        // ignore first and last
+        if (first != null || last != null) {
+            // this index is a table scan, must not use it for lookup
+            throw DbException.throwInternalError(getSQL() + " " + first + " " + last);
+        }
         PageData root = getPage(rootPageId, 0);
         return root.find(session, Long.MIN_VALUE, Long.MAX_VALUE, isMultiVersion);
     }
@@ -422,9 +425,7 @@ public class PageDataIndex extends PageIndex {
     }
 
     public int getColumnIndex(Column col) {
-        if (col.getColumnId() == mainIndexColumn) {
-            return 0;
-        }
+        // can not use this index - use the PageDelegateIndex instead
         return -1;
     }
 

h2/src/main/org/h2/index/PageDelegateIndex.java

@@ -75,7 +75,10 @@ public class PageDelegateIndex extends PageIndex {
     }
 
     public int getColumnIndex(Column col) {
-        return mainIndex.getColumnIndex(col);
+        if (col.getColumnId() == mainIndex.getMainIndexColumn()) {
+            return 0;
+        }
+        return -1;
     }
 
     public double getCost(Session session, int[] masks) {

h2/src/main/org/h2/table/Column.java

@@ -9,7 +9,6 @@ package org.h2.table;
 import java.sql.ResultSetMetaData;
 import java.sql.Time;
 import java.sql.Timestamp;
-
 import org.h2.command.Parser;
 import org.h2.constant.ErrorCode;
 import org.h2.engine.Constants;

h2/src/test/org/h2/test/test-1.2.txt

 --- special grammar and test cases ---------------------------------------------------------------------------------------------
+create table test(id int primary key, d int);
+> ok
+
+insert into test values(1,1), (2, 1);
+> update count: 2
+
+select id from test where id in (1, 2) and d = 1;
+> ID
+> --
+> 1
+> 2
+> rows: 2
+
+drop table test;
+> ok
+
 create table test(id decimal(10, 2) primary key) as select 0;
 > ok