compasses commented on code in PR #11579:
URL: https://github.com/apache/doris/pull/11579#discussion_r945119661
##########
docs/zh-CN/docs/data-table/index/ngram-bloomfilter-index.md:
##########
@@ -0,0 +1,79 @@
+---
+{
+ "title": "NGram BloomFilter索引",
+ "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.
+-->
+
+# Doris NGram BloomFilter索引及使用使用场景
+
+为了提升like的查询性能，增加了NGram BloomFilter索引，其实现主要参照了ClickHouse的ngrambf。
+
+## NGram BloomFilter创建
+
+表创建时指定：
+
+```sql
+CREATE TABLE `table3` (
+ `siteid` int(11) NULL DEFAULT "10" COMMENT "",
+ `citycode` smallint(6) NULL COMMENT "",
+ `username` varchar(32) NULL DEFAULT "" COMMENT "",
+ INDEX idx_ngrambf (`username`) USING NGRAM_BF (3,256) COMMENT 'username
ngram_bf index'
+) ENGINE=OLAP
+AGGREGATE KEY(`siteid`, `citycode`, `username`) COMMENT "OLAP"
+DISTRIBUTED BY HASH(`siteid`) BUCKETS 10
+PROPERTIES (
+"replication_num" = "1"
+);
+
+-- 其中(3,256)，分别表示ngram的个数和bloomfilter的字节数。
+```
+
+## 查看NGram BloomFilter索引
+
+查看我们在表上建立的NGram BloomFilter索引是使用:
+
+```sql
+show index from example_db.table3;
+```
+
+## 删除NGram BloomFilter索引
+
+
+```sql
+alter table example_db.table3 drop index idx_ngrambf;
+```
+
+## 修改NGram BloomFilter索引
+
+为已有列新增NGram BloomFilter索引：
+
+```sql
+alter table example_db.table3 add index idx_ngrambf(username) using
NGRAM_BF(3, 256) comment 'username ngram_bf index'
+```
+
+## **Doris NGram BloomFilter使用注意事项**
+
+1. NGram BloomFilter只支持字符串列
+2. NGram BloomFilter索引和BloomFilter索引为互斥关系，即同一个列只能设置两者中的一个
Review Comment:
Functionally, that's work if add whole value as a token. But I just doubt
it can make things more confusing, since NGram index, has gram size, how about
the whole value length less than the gram size during query? Which will make
the original logic complex, and probable has some impact for the NGram index.
So I concern about this kind of extension. I think it's better to let our user
clear about the NGram index just for like query.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org
For additional commands, e-mail: commits-h...@doris.apache.org
