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[Docs] update data types doc and fix some typo (apache#4712)
* update data types doc and fix some typo * update data types doc and fix some typo Co-authored-by: lixueyan07 <[email protected]>
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--- | ||
{ | ||
"title": "BITMAP", | ||
"language": "en" | ||
} | ||
--- | ||
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<!-- | ||
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. | ||
--> | ||
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#BITMAP | ||
## Description | ||
BITMAP | ||
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BITMAP cannot be used as a key column, and the aggregation type is BITMAP_UNION when building the table. | ||
The user does not need to specify the length and default value. The length is controlled within the system according to the degree of data aggregation. | ||
And the BITMAP column can only be queried or used by supporting functions such as bitmap_union_count, bitmap_union, and bitmap_hash. | ||
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The use of BITMAP in offline scenarios will affect the import speed. In the case of a large amount of data, the query speed will be slower than HLL and better than Count Distinct. | ||
Note: If BITMAP does not use a global dictionary in real-time scenarios, using bitmap_hash() may cause an error of about one-thousandth. | ||
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## example | ||
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select hour, BITMAP_UNION_COUNT(pv) over(order by hour) uv from( | ||
select hour, BITMAP_UNION(device_id) as pv | ||
from metric_table -- Query the accumulated UV per hour | ||
where datekey=20200922 | ||
group by hour order by 1 | ||
) final; | ||
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## keyword | ||
BITMAP |
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docs/en/sql-reference/sql-statements/Data Types/HLL(HyperLogLog).md
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--- | ||
{ | ||
"title": "HLL (HyperLogLog)", | ||
"language": "en" | ||
} | ||
--- | ||
|
||
<!-- | ||
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. | ||
--> | ||
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#HLL (HyperLogLog) | ||
## Description | ||
HLL | ||
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HLL cannot be used as a key column, and the aggregation type is HLL_UNION when create table. | ||
The user does not need to specify the length and default value. | ||
The length is controlled within the system according to the degree of data aggregation. | ||
And HLL columns can only be queried or used through the matching hll_union_agg, hll_raw_agg, hll_cardinality, and hll_hash. | ||
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HLL is approximate count of distinct elements, and its performance is better than Count Distinct when the amount of data is large. | ||
The error of HLL is usually around 1%, sometimes up to 2%. | ||
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## example | ||
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select hour, HLL_UNION_AGG(pv) over(order by hour) uv from( | ||
select hour, HLL_RAW_AGG(device_id) as pv | ||
from metric_table -- Query the accumulated UV per hour | ||
where datekey=20200922 | ||
group by hour order by 1 | ||
) final; | ||
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## keyword | ||
HLL,HYPERLOGLOG |
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48
docs/zh-CN/sql-reference/sql-statements/Data Types/BITMAP.md
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--- | ||
{ | ||
"title": "BITMAP", | ||
"language": "zh-CN" | ||
} | ||
--- | ||
|
||
<!-- | ||
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. | ||
--> | ||
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# BITMAP | ||
## description | ||
BITMAP | ||
BITMAP不能作为key列使用,建表时配合聚合类型为BITMAP_UNION。 | ||
用户不需要指定长度和默认值。长度根据数据的聚合程度系统内控制。 | ||
并且BITMAP列只能通过配套的bitmap_union_count、bitmap_union、bitmap_hash等函数进行查询或使用。 | ||
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离线场景下使用BITMAP会影响导入速度,在数据量大的情况下查询速度会慢于HLL,并优于Count Distinct。 | ||
注意:实时场景下BITMAP如果不使用全局字典,使用了bitmap_hash()可能会导致有千分之一左右的误差。 | ||
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## example | ||
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select hour, BITMAP_UNION_COUNT(pv) over(order by hour) uv from( | ||
select hour, BITMAP_UNION(device_id) as pv | ||
from metric_table -- 查询每小时的累计UV | ||
where datekey=20200622 | ||
group by hour order by 1 | ||
) final; | ||
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## keyword | ||
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BITMAP |
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