Merge pull request #989 from katzyn/range_table

Fix more issues with range table and improve its documentation

h2/src/docsrc/html/systemtables.html

@@ -37,12 +37,27 @@ of all tables in the database as well as the current settings.
 <h2 id="range_table" class="notranslate">Range Table</h2>
 <p>
 The range table is a dynamic system table that contains all values from a start to an end value.
-The table contains one column called X. Both the start and end values are included in the result.
+Non-zero step value may be also specified, default is 1.
+Start value, end value, and optional step value are converted to BIGINT data type.
+The table contains one column called X.
+If start value is greater than end value and step is positive the result is empty.
+If start value is less than end value and step is negative the result is empty too.
+If start value is equal to end value the result contains only start value.
+Start value, start value plus step, start value plus step multiplied by two and so on are included in result.
+If step is positive the last value is less than or equal to the specified end value.
+If step in negative the last value is greater than or equal to the specified end value.
 The table is used as follows:
 </p>
-<p>Example:</p>
+<p>Examples:</p>
 <pre>
 SELECT X FROM SYSTEM_RANGE(1, 10);
+-- 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
+SELECT X FROM SYSTEM_RANGE(1, 10, 2);
+-- 1, 3, 5, 7, 9
+SELECT X FROM SYSTEM_RANGE(1, 10, -1);
+-- No rows
+SELECT X FROM SYSTEM_RANGE(10, 2, -2);
+-- 10, 8, 6, 4, 2
 </pre>
 
 <!-- [close] { --></div></td></tr></table><!-- } --><!-- analytics --></body></html>

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

@@ -90,7 +90,7 @@ public class HashIndex extends BaseIndex {
 
     @Override
     public long getRowCount(Session session) {
-        return getRowCountApproximation();
+        return rows.size();
     }
 
     @Override

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

@@ -47,20 +47,34 @@ public class RangeIndex extends BaseIndex {
 
     @Override
     public Cursor find(Session session, SearchRow first, SearchRow last) {
-        long min = rangeTable.getMin(session), start = min;
-        long max = rangeTable.getMax(session), end = max;
+        long min = rangeTable.getMin(session);
+        long max = rangeTable.getMax(session);
         long step = rangeTable.getStep(session);
         try {
-            start = Math.max(min, first == null ? min : first.getValue(0).getLong());
+            long v = first.getValue(0).getLong();
+            if (step > 0) {
+                if (v > min) {
+                    min += (v - min + step - 1) / step * step;
+                }
+            } else if (v > max) {
+                max = v;
+            }
         } catch (Exception e) {
             // error when converting the value - ignore
         }
         try {
-            end = Math.min(max, last == null ? max : last.getValue(0).getLong());
+            long v = last.getValue(0).getLong();
+            if (step > 0) {
+                if (v < max) {
+                    max = v;
+                }
+            } else if (v < min) {
+                min -= (min - v - step - 1) / step * step;
+            }
         } catch (Exception e) {
             // error when converting the value - ignore
         }
-        return new RangeCursor(session, start, end, step);
+        return new RangeCursor(session, min, max, step);
     }
 
     @Override
@@ -108,7 +122,7 @@ public class RangeIndex extends BaseIndex {
 
     @Override
     public long getRowCount(Session session) {
-        return rangeTable.getRowCountApproximation();
+        return rangeTable.getRowCount(session);
     }
 
     @Override

h2/src/test/org/h2/test/scripts/range_table.sql

@@ -3,6 +3,80 @@
 -- Initial Developer: H2 Group
 --
 
+explain select * from system_range(1, 2) where x=x+1 and x=1;
+> PLAN
+> ---------------------------------------------------------------------------------------------------------------------------------
+> SELECT SYSTEM_RANGE.X FROM SYSTEM_RANGE(1, 2) /* PUBLIC.RANGE_INDEX: X = 1 */ WHERE ((X = 1) AND (X = (X + 1))) AND (1 = (X + 1))
+> rows: 1
+
+explain select * from system_range(1, 2) where not (x = 1 and x*2 = 2);
+> PLAN
+> -------------------------------------------------------------------------------------------------------
+> SELECT SYSTEM_RANGE.X FROM SYSTEM_RANGE(1, 2) /* PUBLIC.RANGE_INDEX */ WHERE (X <> 1) OR ((X * 2) <> 2)
+> rows: 1
+
+explain select * from system_range(1, 10) where (NOT x >= 5);
+> PLAN
+> ------------------------------------------------------------------------------------------
+> SELECT SYSTEM_RANGE.X FROM SYSTEM_RANGE(1, 10) /* PUBLIC.RANGE_INDEX: X < 5 */ WHERE X < 5
+> rows: 1
+
+select (select t1.x from system_range(1,1) t2) from system_range(1,1) t1;
+> SELECT T1.X FROM SYSTEM_RANGE(1, 1) T2 /* PUBLIC.RANGE_INDEX */ /* scanCount: 2 */
+> ----------------------------------------------------------------------------------
+> 1
+> rows: 1
+
+EXPLAIN PLAN FOR SELECT * FROM SYSTEM_RANGE(1, 20);
+> PLAN
+> -----------------------------------------------------------------------
+> SELECT SYSTEM_RANGE.X FROM SYSTEM_RANGE(1, 20) /* PUBLIC.RANGE_INDEX */
+> rows: 1
+
+select sum(x) from system_range(2, 1000) r where
+not exists(select * from system_range(2, 32) r2 where r.x>r2.x and mod(r.x, r2.x)=0);
+> SUM(X)
+> ------
+> 76127
+> rows: 1
+
+SELECT COUNT(*) FROM SYSTEM_RANGE(0, 2111222333);
+> COUNT(*)
+> ----------
+> 2111222334
+> rows: 1
+
+select * from system_range(2, 100) r where
+not exists(select * from system_range(2, 11) r2 where r.x>r2.x and mod(r.x, r2.x)=0);
+> X
+> --
+> 11
+> 13
+> 17
+> 19
+> 2
+> 23
+> 29
+> 3
+> 31
+> 37
+> 41
+> 43
+> 47
+> 5
+> 53
+> 59
+> 61
+> 67
+> 7
+> 71
+> 73
+> 79
+> 83
+> 89
+> 97
+> rows: 25
+
 SELECT * FROM SYSTEM_RANGE(1, 10) ORDER BY 1;
 > X
 > --
@@ -118,3 +192,57 @@ SELECT * FROM SYSTEM_RANGE(2, 1, 0);
 
 SELECT COUNT(*) FROM SYSTEM_RANGE(2, 1, 0);
 > exception
+
+SELECT * FROM SYSTEM_RANGE(1, 8, 2);
+> X
+> -
+> 1
+> 3
+> 5
+> 7
+> rows: 4
+
+SELECT * FROM SYSTEM_RANGE(1, 8, 2) WHERE X = 2;
+> X
+> -
+> rows: 0
+
+SELECT COUNT(*) FROM SYSTEM_RANGE(1, 8, 2) WHERE X = 2;
+>> 0
+
+SELECT * FROM SYSTEM_RANGE(1, 8, 2) WHERE X BETWEEN 2 AND 6;
+> X
+> -
+> 3
+> 5
+> rows: 2
+
+SELECT COUNT(*) FROM SYSTEM_RANGE(1, 8, 2) WHERE X BETWEEN 2 AND 6;
+>> 2
+
+SELECT * FROM SYSTEM_RANGE(8, 1, -2) ORDER BY X DESC;
+> X
+> -
+> 8
+> 6
+> 4
+> 2
+> rows (ordered): 4
+
+SELECT * FROM SYSTEM_RANGE(8, 1, -2) WHERE X = 3;
+> X
+> -
+> rows: 0
+
+SELECT COUNT(*) FROM SYSTEM_RANGE(8, 1, -2) WHERE X = 3;
+>> 0
+
+SELECT * FROM SYSTEM_RANGE(8, 1, -2) WHERE X BETWEEN 3 AND 7 ORDER BY 1 DESC;
+> X
+> -
+> 6
+> 4
+> rows (ordered): 2
+
+SELECT COUNT(*) FROM SYSTEM_RANGE(8, 1, -2) WHERE X BETWEEN 3 AND 7;
+>> 2

h2/src/test/org/h2/test/scripts/testScript.sql

@@ -1950,24 +1950,6 @@ create table test as select 1, space(10) from dual where 1=0 union all select x,
 drop table test;
 > ok
 
-explain select * from system_range(1, 2) where x=x+1 and x=1;
-> PLAN
-> ---------------------------------------------------------------------------------------------------------------------------------
-> SELECT SYSTEM_RANGE.X FROM SYSTEM_RANGE(1, 2) /* PUBLIC.RANGE_INDEX: X = 1 */ WHERE ((X = 1) AND (X = (X + 1))) AND (1 = (X + 1))
-> rows: 1
-
-explain select * from system_range(1, 2) where not (x = 1 and x*2 = 2);
-> PLAN
-> -------------------------------------------------------------------------------------------------------
-> SELECT SYSTEM_RANGE.X FROM SYSTEM_RANGE(1, 2) /* PUBLIC.RANGE_INDEX */ WHERE (X <> 1) OR ((X * 2) <> 2)
-> rows: 1
-
-explain select * from system_range(1, 10) where (NOT x >= 5);
-> PLAN
-> ------------------------------------------------------------------------------------------
-> SELECT SYSTEM_RANGE.X FROM SYSTEM_RANGE(1, 10) /* PUBLIC.RANGE_INDEX: X < 5 */ WHERE X < 5
-> rows: 1
-
 CREATE TABLE TEST(ID INT PRIMARY KEY, NAME VARCHAR(255));
 > ok
 
@@ -3042,12 +3024,6 @@ SELECT t1.ID, (SELECT t1.id || ':' || AVG(t2.ID) FROM X t2) FROM X t1;
 drop table x;
 > ok
 
-select (select t1.x from system_range(1,1) t2) from system_range(1,1) t1;
-> SELECT T1.X FROM SYSTEM_RANGE(1, 1) T2 /* PUBLIC.RANGE_INDEX */ /* scanCount: 2 */
-> ----------------------------------------------------------------------------------
-> 1
-> rows: 1
-
 create table test(id int primary key, name varchar);
 > ok
 
@@ -5872,12 +5848,6 @@ EXPLAIN PLAN FOR SELECT LEFT(NAME, 2) FROM TEST;
 > SELECT LEFT(NAME, 2) FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */
 > rows: 1
 
-EXPLAIN PLAN FOR SELECT * FROM SYSTEM_RANGE(1, 20);
-> PLAN
-> -----------------------------------------------------------------------
-> SELECT SYSTEM_RANGE.X FROM SYSTEM_RANGE(1, 20) /* PUBLIC.RANGE_INDEX */
-> rows: 1
-
 SELECT * FROM test t1 inner join test t2 on t1.id=t2.id and t2.name is not null where t1.id=1;
 > ID NAME  ID NAME
 > -- ----- -- -----
@@ -6358,54 +6328,6 @@ SELECT * FROM TEST;
 DROP TABLE TEST;
 > ok
 
---- range ----------------------------------------------------------------------------------------------
---import java.math.*;
---int s=0;for(int i=2;i<=1000;i++)
---s+=BigInteger.valueOf(i).isProbablePrime(10000)?i:0;s;
-select sum(x) from system_range(2, 1000) r where
-not exists(select * from system_range(2, 32) r2 where r.x>r2.x and mod(r.x, r2.x)=0);
-> SUM(X)
-> ------
-> 76127
-> rows: 1
-
-SELECT COUNT(*) FROM SYSTEM_RANGE(0, 2111222333);
-> COUNT(*)
-> ----------
-> 2111222334
-> rows: 1
-
-select * from system_range(2, 100) r where
-not exists(select * from system_range(2, 11) r2 where r.x>r2.x and mod(r.x, r2.x)=0);
-> X
-> --
-> 11
-> 13
-> 17
-> 19
-> 2
-> 23
-> 29
-> 3
-> 31
-> 37
-> 41
-> 43
-> 47
-> 5
-> 53
-> 59
-> 61
-> 67
-> 7
-> 71
-> 73
-> 79
-> 83
-> 89
-> 97
-> rows: 25
-
 --- syntax errors ----------------------------------------------------------------------------------------------
 CREATE SOMETHING STRANGE;
 > exception