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The following commit(s) were added to refs/heads/master by this push:
new 689a5a495 [core] Remove count function because it cannot be
implemented correctly (#3932)
689a5a495 is described below
commit 689a5a49544e186b26f5a988732f5e97f3405187
Author: monster <[email protected]>
AuthorDate: Sun Aug 11 21:06:13 2024 +0800
[core] Remove count function because it cannot be implemented correctly
(#3932)
---
.../primary-key-table/merge-engine/aggregation.md | 12 ++-
.../compact/aggregate/FieldAggregator.java | 3 -
.../mergetree/compact/aggregate/FieldCountAgg.java | 100 ---------------------
.../compact/aggregate/FieldAggregatorTest.java | 31 -------
4 files changed, 9 insertions(+), 137 deletions(-)
diff --git a/docs/content/primary-key-table/merge-engine/aggregation.md
b/docs/content/primary-key-table/merge-engine/aggregation.md
index 7cdd9044a..27b29ed5b 100644
--- a/docs/content/primary-key-table/merge-engine/aggregation.md
+++ b/docs/content/primary-key-table/merge-engine/aggregation.md
@@ -71,8 +71,14 @@ Current supported aggregate functions and data types are:
It supports DECIMAL, TINYINT, SMALLINT, INTEGER, BIGINT, FLOAT, and DOUBLE
data types.
### count
- The count function counts the values across multiple rows.
- It supports INTEGER, BIGINT data types.
+ In scenarios where counting rows that match a specific condition is
required, you can use the SUM function to achieve this. By expressing a
condition as a Boolean value (TRUE or FALSE) and converting it into a numerical
value, you can effectively count the rows. In this approach, TRUE is converted
to 1, and FALSE is converted to 0.
+
+ For example, if you have a table orders and want to count the number of rows
that meet a specific condition, you can use the following query:
+ ```sql
+ SELECT SUM(CASE WHEN condition THEN 1 ELSE 0 END) AS count
+ FROM orders;
+ ```
+
### max
The max function identifies and retains the maximum value.
@@ -261,7 +267,7 @@ For streaming queries, `aggregation` merge engine must be
used together with `lo
## Retraction
-Only `sum`, `product`, `count`, `collect`, `merge_map`, `nested_update`,
`last_value` and `last_non_null_value` supports retraction (`UPDATE_BEFORE` and
`DELETE`), others aggregate functions do not support retraction.
+Only `sum`, `product`, `collect`, `merge_map`, `nested_update`, `last_value`
and `last_non_null_value` supports retraction (`UPDATE_BEFORE` and `DELETE`),
others aggregate functions do not support retraction.
If you allow some functions to ignore retraction messages, you can configure:
`'fields.${field_name}.ignore-retract'='true'`.
diff --git
a/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregator.java
b/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregator.java
index 8d0f5b79f..b3fb7b0eb 100644
---
a/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregator.java
+++
b/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregator.java
@@ -89,9 +89,6 @@ public abstract class FieldAggregator implements Serializable
{
case FieldFirstNonNullValueAgg.LEGACY_NAME:
fieldAggregator = new
FieldFirstNonNullValueAgg(fieldType);
break;
- case FieldCountAgg.NAME:
- fieldAggregator = new FieldCountAgg(fieldType);
- break;
case FieldProductAgg.NAME:
fieldAggregator = new FieldProductAgg(fieldType);
break;
diff --git
a/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldCountAgg.java
b/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldCountAgg.java
deleted file mode 100644
index 0c1d8c094..000000000
---
a/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldCountAgg.java
+++ /dev/null
@@ -1,100 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements. See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership. The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.paimon.mergetree.compact.aggregate;
-
-import org.apache.paimon.types.DataType;
-
-/** count value aggregate a field of a row. */
-public class FieldCountAgg extends FieldAggregator {
-
- public static final String NAME = "count";
-
- public FieldCountAgg(DataType dataType) {
- super(dataType);
- }
-
- @Override
- String name() {
- return NAME;
- }
-
- @Override
- public Object agg(Object accumulator, Object inputField) {
-
- if (accumulator != null && inputField == null) {
- return accumulator;
- }
- // ordered by type root definition
- switch (fieldType.getTypeRoot()) {
- case TINYINT:
- return accumulator == null
- ? (inputField == null ? (byte) 0 : (byte) 1)
- : (byte) ((byte) accumulator + 1);
- case SMALLINT:
- return accumulator == null
- ? (inputField == null ? (short) 0 : (short) 1)
- : (short) ((short) accumulator + 1);
- case INTEGER:
- return accumulator == null ? (inputField == null ? 0 : 1) :
(int) accumulator + 1;
- case BIGINT:
- return accumulator == null
- ? (inputField == null ? 0L : 1L)
- : (long) accumulator + 1L;
- default:
- String msg =
- String.format(
- "type %s not support in %s",
- fieldType.getTypeRoot().toString(),
this.getClass().getName());
- throw new IllegalArgumentException(msg);
- }
- }
-
- @Override
- public Object retract(Object accumulator, Object inputField) {
-
- if (accumulator != null && inputField == null) {
- return accumulator;
- }
-
- // ordered by type root definition
- switch (fieldType.getTypeRoot()) {
- case TINYINT:
- return accumulator == null
- ? (inputField == null ? (byte) 0 : (byte) -1)
- : (byte) ((byte) accumulator - 1);
- case SMALLINT:
- return accumulator == null
- ? (inputField == null ? (short) 0 : (short) -1)
- : (short) ((short) accumulator - 1);
- case INTEGER:
- return accumulator == null ? (inputField == null ? 0 : -1) :
(int) accumulator - 1;
-
- case BIGINT:
- return accumulator == null
- ? (inputField == null ? 0L : -1L)
- : (long) accumulator - 1L;
- default:
- String msg =
- String.format(
- "type %s not support in %s",
- fieldType.getTypeRoot().toString(),
this.getClass().getName());
- throw new IllegalArgumentException(msg);
- }
- }
-}
diff --git
a/paimon-core/src/test/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregatorTest.java
b/paimon-core/src/test/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregatorTest.java
index 7fae50622..b0ae2c5c0 100644
---
a/paimon-core/src/test/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregatorTest.java
+++
b/paimon-core/src/test/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregatorTest.java
@@ -175,37 +175,6 @@ public class FieldAggregatorTest {
assertThat(fieldSumAgg.retract(null, 5)).isEqualTo(-5);
}
- @Test
- public void testFieldCountIntAgg() {
- FieldCountAgg fieldCountAggInt = new FieldCountAgg(new IntType());
- assertThat(fieldCountAggInt.agg(null, null)).isEqualTo(0);
- assertThat(fieldCountAggInt.agg(1, null)).isEqualTo(1);
- assertThat(fieldCountAggInt.agg(null, 15)).isEqualTo(1);
- assertThat(fieldCountAggInt.agg(1, 0)).isEqualTo(2);
- assertThat(fieldCountAggInt.agg(3, 6)).isEqualTo(4);
-
- FieldCountAgg fieldCountAggLong = new FieldCountAgg(new BigIntType());
- assertThat(fieldCountAggLong.agg(null, null)).isEqualTo(0L);
- assertThat(fieldCountAggLong.agg((long) 1, null)).isEqualTo((long) 1);
- assertThat(fieldCountAggLong.agg(null, (long) 15)).isEqualTo(1L);
- assertThat(fieldCountAggLong.agg((long) 1, 0)).isEqualTo((long) 2);
- assertThat(fieldCountAggLong.agg((long) 3, (long) 6)).isEqualTo((long)
4);
-
- FieldCountAgg fieldCountAggByte = new FieldCountAgg(new TinyIntType());
- assertThat(fieldCountAggByte.agg(null, null)).isEqualTo((byte) 0);
- assertThat(fieldCountAggByte.agg((byte) 1, null)).isEqualTo((byte) 1);
- assertThat(fieldCountAggByte.agg(null, (byte) 15)).isEqualTo((byte) 1);
- assertThat(fieldCountAggByte.agg((byte) 1, 0)).isEqualTo((byte) 2);
- assertThat(fieldCountAggByte.agg((byte) 3, (byte) 6)).isEqualTo((byte)
4);
-
- FieldCountAgg fieldCountAggShort = new FieldCountAgg(new
SmallIntType());
- assertThat(fieldCountAggShort.agg(null, null)).isEqualTo((short) 0);
- assertThat(fieldCountAggShort.agg((short) 1, null)).isEqualTo((short)
1);
- assertThat(fieldCountAggShort.agg(null, (short) 15)).isEqualTo((short)
1);
- assertThat(fieldCountAggShort.agg((short) 1, 0)).isEqualTo((short) 2);
- assertThat(fieldCountAggShort.agg((short) 3, (short)
6)).isEqualTo((short) 4);
- }
-
@Test
public void testFieldProductIntAgg() {
FieldProductAgg fieldProductAgg = new FieldProductAgg(new IntType());
