diff --git a/documentation20/cn/05.insert/docs.md b/documentation20/cn/05.insert/docs.md
index 4f931f6bbc42089028a911ac5ac701672d1e4f19..7e28d6de1a25c7f516472097caef28d05a97854f 100644
--- a/documentation20/cn/05.insert/docs.md
+++ b/documentation20/cn/05.insert/docs.md
@@ -26,7 +26,7 @@ INSERT INTO d1001 VALUES (1538548685000, 10.3, 219, 0.31) (1538548695000, 12.6,
 
 **Tips:**
 
-- 要提高写入效率，需要批量写入。一批写入的记录条数越多，插入效率就越高。但一条记录不能超过 16K，一条 SQL 语句总长度不能超过 1M 。
+- 要提高写入效率，需要批量写入。一批写入的记录条数越多，插入效率就越高。但一条记录不能超过 48K（2.1.7.0 之前的版本为 16K），一条 SQL 语句总长度不能超过 1M 。
 - TDengine 支持多线程同时写入，要进一步提高写入速度，一个客户端需要打开 20 个以上的线程同时写。但线程数达到一定数量后，无法再提高，甚至还会下降，因为线程频繁切换，带来额外开销。
 - 对同一张表，如果新插入记录的时间戳已经存在，默认情形下（UPDATE=0）新记录将被直接抛弃，也就是说，在一张表里，时间戳必须是唯一的。如果应用自动生成记录，很有可能生成的时间戳是一样的，这样，成功插入的记录条数会小于应用插入的记录条数。如果在创建数据库时使用了 UPDATE 1 选项，插入相同时间戳的新记录将覆盖原有记录。
 - 写入的数据的时间戳必须大于当前时间减去配置参数 keep 的时间。如果 keep 配置为3650天，那么无法写入比 3650 天还早的数据。写入数据的时间戳也不能大于当前时间加配置参数 days。如果 days 为 2，那么无法写入比当前时间还晚2天的数据。
@@ -103,7 +103,7 @@ st,t1=3,t2=4,t3=t3 c1=3i64,c3="passit",c2=false,c4=4f64 1626006833639000000
 <br/>8. 整个处理过程中遇到的错误会中断写入过程，并返回错误代码。
 
 **备注：**
-<br/>无模式所有的处理逻辑，仍会遵循 TDengine 对数据结构的底层限制，例如每行数据的总长度不能超过 16k 字节。这方面的具体限制约束请参见 [TAOS SQL 边界限制](https://www.taosdata.com/cn/documentation/taos-sql#limitation) 章节。
+<br/>无模式所有的处理逻辑，仍会遵循 TDengine 对数据结构的底层限制，例如每行数据的总长度不能超过 48K 字节（2.1.7.0 之前的版本为 16K）。这方面的具体限制约束请参见 [TAOS SQL 边界限制](https://www.taosdata.com/cn/documentation/taos-sql#limitation) 章节。
 
 **时间分辨率识别**
 <br/>无模式写入过程中支持三个指定的模式，具体如下
diff --git a/documentation20/cn/11.administrator/docs.md b/documentation20/cn/11.administrator/docs.md
index b6ec3affe3080662c9d2e4a09c8dbb41a79ae36a..d8be0e8fddbf2bfc00ca9f44b2e7dba29a0274c8 100644
--- a/documentation20/cn/11.administrator/docs.md
+++ b/documentation20/cn/11.administrator/docs.md
@@ -1839,11 +1839,11 @@ rmtaos
 去掉了 ```‘“`\```  (单双引号、撇号、反斜杠、空格)
 
 - 数据库名：不能包含“.”以及特殊字符，不能超过 32 个字符
-- 表名：不能包含“.”以及特殊字符，与所属数据库名一起，不能超过 192 个字符，每行数据最大长度 16k 个字符
+- 表名：不能包含“.”以及特殊字符，与所属数据库名一起，不能超过 192 个字符。每行数据最大长度 48K 个字符（2.1.7.0 之前的版本为 16K，每个 BINARY/NCHAR 类型的列还会额外占用 2 个 byte 的存储位置）
 - 表的列名：不能包含特殊字符，不能超过 64 个字符
 - 数据库名、表名、列名，都不能以数字开头，合法的可用字符集是“英文字符、数字和下划线”
 - 表的列数：不能超过 1024 列，最少需要 2 列，第一列必须是时间戳（从 2.1.7.0 版本开始，改为最多支持 4096 列）
-- 记录的最大长度：包括时间戳 8 byte，不能超过 16KB（每个 BINARY/NCHAR 类型的列还会额外占用 2 个 byte 的存储位置）
+- 记录的最大长度：包括时间戳 8 byte，不能超过 48KB（2.1.7.0 之前的版本为 16K，每个 BINARY/NCHAR 类型的列还会额外占用 2 个 byte 的存储位置）
 - 单条 SQL 语句默认最大字符串长度：1048576 byte，但可通过系统配置参数 maxSQLLength 修改，取值范围 65480 ~ 1048576 byte
 - 数据库副本数：不能超过 3
 - 用户名：不能超过 23 个 byte
diff --git a/documentation20/cn/12.taos-sql/docs.md b/documentation20/cn/12.taos-sql/docs.md
index 05fbfb7389e18ce357103afeb0ec96b2c7b99673..025065fe9e82e6e98aeba436834e9eb3487b2f4b 100755
--- a/documentation20/cn/12.taos-sql/docs.md
+++ b/documentation20/cn/12.taos-sql/docs.md
@@ -172,7 +172,7 @@ CREATE DATABASE db_name PRECISION 'ns';
 
     2) 表名最大长度为 192；
 
-    3) 表的每行长度不能超过 16k 个字符;（注意：每个 BINARY/NCHAR 类型的列还会额外占用 2 个字节的存储位置）
+    3) 表的每行长度不能超过 48K 个字符（2.1.7.0 之前的版本为 16K，每个 BINARY/NCHAR 类型的列还会额外占用 2 个 byte 的存储位置）
 
     4) 子表名只能由字母、数字和下划线组成，且不能以数字开头，不区分大小写
 
@@ -346,7 +346,7 @@ CREATE DATABASE db_name PRECISION 'ns';
     ```mysql
     ALTER STABLE stb_name ADD TAG new_tag_name tag_type;
     ```
-    为 STable 增加一个新的标签，并指定新标签的类型。标签总数不能超过 128 个，总长度不超过 16k 个字符。
+    为 STable 增加一个新的标签，并指定新标签的类型。标签总数不能超过 128 个，总长度不超过 16K 个字符。
 
 - **删除标签**
 
@@ -1732,9 +1732,9 @@ SELECT AVG(current), MAX(current), APERCENTILE(current, 50) FROM meters
 ## <a class="anchor" id="limitation"></a>TAOS SQL 边界限制
 
 - 数据库名最大长度为 32。
-- 表名最大长度为 192，每行数据最大长度 16k 个字符, 从 2.1.7.0 版本开始，每行数据最大长度 48k 个字符（注意：数据行内每个 BINARY/NCHAR 类型的列还会额外占用 2 个字节的存储位置）。
+- 表名最大长度为 192。每行数据最大长度 48K 个字符（2.1.7.0 之前的版本为 16K，每个 BINARY/NCHAR 类型的列还会额外占用 2 个 byte 的存储位置）
 - 列名最大长度为 64，最多允许 1024 列，最少需要 2 列，第一列必须是时间戳。（从 2.1.7.0 版本开始，改为最多允许 4096 列）
-- 标签名最大长度为 64，最多允许 128 个，可以 1 个，一个表中标签值的总长度不超过 16k 个字符。
+- 标签名最大长度为 64，最多允许 128 个，可以 1 个，一个表中标签值的总长度不超过 16K 个字符。
 - SQL 语句最大长度 1048576 个字符，也可通过客户端配置参数 maxSQLLength 修改，取值范围 65480 ~ 1048576。
 - SELECT 语句的查询结果，最多允许返回 1024 列（语句中的函数调用可能也会占用一些列空间），超限时需要显式指定较少的返回数据列，以避免语句执行报错。（从 2.1.7.0 版本开始，改为最多允许 4096 列）
 - 库的数目，超级表的数目、表的数目，系统不做限制，仅受系统资源限制。
diff --git a/documentation20/en/05.insert/docs.md b/documentation20/en/05.insert/docs.md
index 0527b728f348e1eb20298b2dd077ec3c11f1cc88..76be97d4f2cfefa4eaecdbc8c1f7a125e5d3cd54 100644
--- a/documentation20/en/05.insert/docs.md
+++ b/documentation20/en/05.insert/docs.md
@@ -26,7 +26,7 @@ For the SQL INSERT Grammar, please refer to  [Taos SQL insert](https://www.taosd
 
 **Tips:**
 
-- To improve writing efficiency, batch writing is required. The more records written in a batch, the higher the insertion efficiency. However, a record size cannot exceed 16K, and the total length of an SQL statement cannot exceed 64K (it can be configured by parameter maxSQLLength, and the maximum can be configured to 1M).
+- To improve writing efficiency, batch writing is required. The more records written in a batch, the higher the insertion efficiency. However, a record size cannot exceed 48K (it's 16K prior to 2.1.7.0, and the total length of an SQL statement cannot exceed 64K (it can be configured by parameter maxSQLLength, and the maximum can be configured to 1M).
 - TDengine supports multi-thread parallel writing. To further improve writing speed, a client needs to open more than 20 threads to write parallelly. However, after the number of threads reaches a certain threshold, it cannot be increased or even become decreased, because too much thread switching brings extra overhead.
 - For the same table, if the timestamp of a newly inserted record already exists, the new record will be discarded as default (database option update = 0), that is, the timestamp must be unique in a table. If an application automatically generates records, it is very likely that the generated timestamps will be the same, so the number of records successfully inserted will be smaller than the number of records the application try to insert. If you use UPDATE 1 option when creating a database, inserting a new record with the same timestamp will overwrite the original record.
 - The timestamp of written data must be greater than the current time minus the time of configuration parameter keep. If keep is configured for 3650 days, data older than 3650 days cannot be written. The timestamp for writing data cannot be greater than the current time plus configuration parameter days. If days is configured to 2, data 2 days later than the current time cannot be written.
@@ -95,7 +95,7 @@ After MD5 value "md5_val" calculated using the above string, prefix "t_" is prep
 <br/>8. If any error occurs during processing, error code will be returned.
 
 **Note**
-<br/>Schemaless will follow TDengine data structure limitations. For example, each table row cannot exceed 16KB. For detailed TDengine limitations please refer to `https://www.taosdata.com/en/documentation/taos-sql#limitation`.
+<br/>Schemaless will follow TDengine data structure limitations. For example, each table row cannot exceed 48KB (it's 16K prior to 2.1.7.0. For detailed TDengine limitations please refer to `https://www.taosdata.com/en/documentation/taos-sql#limitation`.
 
 **Timestamp precisions**
 <br/>Following protocols are supported in Schemaless:
diff --git a/documentation20/en/11.administrator/docs.md b/documentation20/en/11.administrator/docs.md
index 5ca65b24ec3adde7fd04bcfc33f802b003670061..59955c76a175b44cac3f3164ed6514effd35dc65 100644
--- a/documentation20/en/11.administrator/docs.md
+++ b/documentation20/en/11.administrator/docs.md
@@ -91,12 +91,12 @@ Only some important configuration parameters are listed below. For more paramete
 - firstEp: end point of the first dnode which will be connected in the cluster when taosd starts, the default value is localhost: 6030.
 - fqdn: FQDN of the data node, which defaults to the first hostname configured by the operating system. If you want to access via IP address directly, you can set it to the IP address of the node.
 - serverPort: the port number of the external service after taosd started, the default value is 6030.
-- httpPort: the port number used by the RESTful service to which all HTTP requests (TCP) require a query/write request. The default value is 6041. Note 2.4 and later version use a stand-alone software, taosAdapter to provide RESTFul interface.
+- httpPort: the port number used by the RESTful service to which all HTTP requests (TCP) require a query/write request. The default value is 6041. Note 2.4 and later version use a stand-alone software, taosAdapter to provide RESTful interface.
 - dataDir: the data file directory to which all data files will be written. `Default:/var/lib/taos`.
 - logDir: the log file directory to which the running log files of the client and server will be written. `Default:/var/log/taos`.
 - arbitrator: the end point of the arbitrator in the system; the default value is null.
 - role: optional role for dnode. 0-any; it can be used as an mnode and to allocate vnodes; 1-mgmt; It can only be an mnode, but not to allocate vnodes; 2-dnode; cannot be an mnode, only vnode can be allocated
-- debugFlage: run the log switch. 131 (output error and warning logs), 135 (output error, warning, and debug logs), 143 (output error, warning, debug, and trace logs). Default value: 131 or 135 (different modules have different default values).
+- debugFlags: run the log switch. 131 (output error and warning logs), 135 (output error, warning, and debug logs), 143 (output error, warning, debug, and trace logs). Default value: 131 or 135 (different modules have different default values).
 - numOfLogLines: the maximum number of lines allowed for a single log file. Default: 10,000,000 lines.
 - logKeepDays: the maximum retention time of the log file. When it is greater than 0, the log file will be renamed to taosdlog.xxx, where xxx is the timestamp of the last modification of the log file in seconds. Default: 0 days.
 - maxSQLLength: the maximum length allowed for a single SQL statement. Default: 65380 bytes.
@@ -495,7 +495,7 @@ You can configure different data directories and log directories by modifying sy
 - Table column name: cannot contain special characters, and cannot exceed 64 characters
 - Database name, table name, column name cannot begin with a number
 - Number of columns in table: cannot exceed 1024 columns
-- Maximum length of record: including 8 bytes as timestamp, no more than 16KB (each column of BINARY/NCHAR type will occupy an additional 2 bytes of storage location)
+- Maximum length of record: including 8 bytes as timestamp, no more than 48K bytes (it's 16K bytes prior to 2.1.7.0. each column of BINARY/NCHAR type will occupy an additional 2 bytes of storage location)
 - Default maximum string length for a single SQL statement: 65480 bytes
 - Number of database replicas: no more than 3
 - User name: no more than 23 bytes
diff --git a/documentation20/en/12.taos-sql/docs.md b/documentation20/en/12.taos-sql/docs.md
index 16f85fc0467d3e3215ba1af9c820dd939374019f..cbd2d77a507e0d55f1d870423d517cd1b79aac10 100755
--- a/documentation20/en/12.taos-sql/docs.md
+++ b/documentation20/en/12.taos-sql/docs.md
@@ -34,7 +34,7 @@ With TDengine, the most important thing is timestamp. When creating and insertin
 - Time Format: 'YYYY-MM-DD HH:mm:ss.MS', default in milliseconds. For example,'2017-08-12 18:52:58.128'
 - Internal Function **now** : this is the current time of the server
 - When inserting a record, if timestamp is NOW, then use the server current time.
-- Epch Time: a timestamp value can also be a long integer representing milliseconds since 1970-01-01 08:00:00.000.
+- Epoch Time: a timestamp value can also be a long integer representing milliseconds since 1970-01-01 08:00:00.000.
 - Arithmetic operations can be applied to timestamp. For example: now-2h represents a timestamp which is 2 hours ago from the current server time. Units include u( microsecond), a (milliseconds), s (seconds), m (minutes), h (hours), d (days), w (weeks). In `select * from t1 where ts > now-2w and ts <= now-1w`, which queries data of the whole week before two weeks. To specify the interval of down sampling, you can also use n(calendar month) and y(calendar year) as time units.
 
 TDengine's timestamp is set to millisecond accuracy by default. Microsecond/nanosecond accuracy can be set using CREATE DATABASE with PRECISION parameter. (Nanosecond resolution is supported from version 2.1.5.0 onwards.)
@@ -44,13 +44,13 @@ In TDengine, the following 10 data types can be used in data model of an ordinar
 |      | **Data Type** | **Bytes** | **Note**                                                     |
 | ---- | ------------- | --------- | ------------------------------------------------------------ |
 | 1    | TIMESTAMP     | 8         | Time stamp. Default in milliseconds, and support microseconds. Starting from 1970-01-01 00:00:00. 000 (UTC/GMT), the timing cannot be earlier than this time. |
-| 2    | INT           | 4         | A nullable integer type with a range of [-2^31+1, 2^31-1 ]   |
-| 3    | BIGINT        | 8         | A nullable integer type with a range of [-2^59, 2^59 ]       |
-| 4    | FLOAT         | 4         | A standard nullable float type with 6 -7 significant digits and a range of [-3.4E38, 3.4E38] |
-| 5    | DOUBLE        | 8         | A standard nullable double float type with 15-16 significant digits and a range of [-1.7E308, 1.7E308] |
+| 2    | INT           | 4         | A null-able integer type with a range of [-2^31+1, 2^31-1 ]   |
+| 3    | BIGINT        | 8         | A null-able integer type with a range of [-2^59, 2^59 ]       |
+| 4    | FLOAT         | 4         | A standard null-able float type with 6 -7 significant digits and a range of [-3.4E38, 3.4E38] |
+| 5    | DOUBLE        | 8         | A standard null-able double float type with 15-16 significant digits and a range of [-1.7E308, 1.7E308] |
 | 6    | BINARY        | Custom    | Used to record ASCII strings. Theoretically, the maximum length can be 16,374 bytes, but since each row of data can be up to 16K bytes, the actual limit is generally smaller than the theoretical value. Binary only supports string input, and single quotation marks are used at both ends of the string, otherwise all English will be automatically converted to lowercase. When using, the size must be specified. For example, binary (20) defines a string with a maximum length of 20 characters, and each character occupies 1 byte of storage space. In this case, if the user string exceeds 20 bytes, an error will be reported. For single quotation marks in strings, they can be represented by escape character backslash plus single quotation marks, that is\ '. |
-| 7    | SMALLINT      | 2         | A nullable integer type with a range of [-32767, 32767]      |
-| 8    | TINYINT       | 1         | A nullable integer type with a range of [-127, 127]          |
+| 7    | SMALLINT      | 2         | A null-able integer type with a range of [-32767, 32767]      |
+| 8    | TINYINT       | 1         | A null-able integer type with a range of [-127, 127]          |
 | 9    | BOOL          | 1         | Boolean type，{true, false}                                  |
 | 10   | NCHAR         | Custom    | Used to record non-ASCII strings, such as Chinese characters. Each nchar character takes up 4 bytes of storage space. Single quotation marks are used at both ends of the string, and escape characters are required for single quotation marks in the string, that is \’. When nchar is used, the string size must be specified. A column of type nchar (10) indicates that the string of this column stores up to 10 nchar characters, which will take up 40 bytes of space. If the length of the user string exceeds the declared length, an error will be reported. |
 | 11   | JSON          |           | Json type，only support for tag                                  |
@@ -147,7 +147,7 @@ Note:
   Note:
    1. The first field must be a timestamp, and system will set it as the primary key;
    2. The max length of table name is 192;
-   3. The length of each row of the table cannot exceed 16k characters;
+   3. The length of each row of the table cannot exceed 48K (it's 16K prior to 2.1.7.0) characters;
    4. Sub-table names can only consist of letters, numbers, and underscores, and cannot begin with numbers
    5. If the data type binary or nchar is used, the maximum number of bytes should be specified, such as binary (20), which means 20 bytes;
 
@@ -186,7 +186,7 @@ Note:
 - **Show all data table information under the current database**
 
     ```mysql
-    SHOW TABLES [LIKE tb_name_wildcar];
+    SHOW TABLES [LIKE tb_name_wildcard];
     ```
     Show all data table information under the current database.
     Note: Wildcard characters can be used to match names in like. The maximum length of this wildcard character string cannot exceed 24 bytes.
@@ -236,7 +236,7 @@ Note: In 2.0.15.0 and later versions, STABLE reserved words are supported. That
     1. Data types of TAGS column cannot be timestamp;
     2. No duplicated TAGS column names;
     3. Reversed word cannot be used as a TAGS column name;
-    4. The maximum number of TAGS is 128, and at least 1 TAG allowed, with a total length of no more than 16k characters.
+    4. The maximum number of TAGS is 128, and at least 1 TAG allowed, with a total length of no more than 16K characters.
 
 - **Drop a STable**
 
@@ -409,7 +409,7 @@ SELECT select_expr [, select_expr ...]
 
 #### SELECT Clause
 
-A select clause can be a subquery of UNION and another query.
+A select clause can be a sub-query of UNION and another query.
 
 #### Wildcard character
 
@@ -532,7 +532,7 @@ However, renaming for one single column is not supported for `first(*)`,`last(*)
 
 #### List of STable
 
-The `FROM` keyword can be followed by a list of several tables (STables) or result of a subquery. 
+The `FROM` keyword can be followed by a list of several tables (STables) or result of a sub-query. 
 
 If you do not specify user's current database, you can use the database name before the table name to specify the database to which the table belongs. For example: `power.d1001` to use tables across databases.
 
@@ -686,10 +686,10 @@ Query OK, 1 row(s) in set (0.001091s)
     SELECT (col1 + col2) AS 'complex' FROM tb1 WHERE ts > '2018-06-01 08:00:00.000' AND col2 > 1.2 LIMIT 10 OFFSET 5;
     ```
 
-- Query the records of past 10 minutes, the value of col2 is greater than 3.14, and output the result to the file /home/testoutpu.csv.
+- Query the records of past 10 minutes, the value of col2 is greater than 3.14, and output the result to the file /home/testoutput.csv.
 
     ```mysql
-    SELECT COUNT(*) FROM tb1 WHERE ts >= NOW - 10m AND col2 > 3.14 >> /home/testoutpu.csv;
+    SELECT COUNT(*) FROM tb1 WHERE ts >= NOW - 10m AND col2 > 3.14 >> /home/testoutput.csv;
     ```
 
 <a class="anchor" id="functions"></a>
@@ -1227,9 +1227,9 @@ SELECT AVG(current), MAX(current), LEASTSQUARES(current, start_val, step_val), P
 ## <a class="anchor" id="limitation"></a> TAOS SQL Boundary Restrictions
 
 - Max database name length is 32
-- Max length of table name is 192, and max length of each data row is 16k characters
+- Max length of table name is 192, and max length of each data row is 48K (it's 16K prior to 2.1.7.0) characters
 - Max length of column name is 64, max number of columns allowed is 1024, and min number of columns allowed is 2. The first column must be a timestamp
-- Max number of tags allowed is 128, down to 1, and total length of tags does not exceed 16k characters
+- Max number of tags allowed is 128, down to 1, and total length of tags does not exceed 16K characters
 - Max length of SQL statement is 65480 characters, but it can be modified by system configuration parameter maxSQLLength, and max length can be configured to 1M
 - Number of databases, STables and tables are not limited by system, but only limited by system resources
 
@@ -1355,4 +1355,4 @@ Is not null supports all types of columns. Non-null expression is < > "" and onl
     2. Backquote`` identifier： Keep it as it is.
   - The escape characters that in a data
     3. The escape character defined above will be escaped (% and _ see the description below). If there is no matching escape character, the escape character will be ignored.
-    4. The `\%` and `\_` sequences are used to search for literal instances of % and _ in pattern-matching contexts where they would otherwise be interpreted as wildcard characters.If you use `\%` or `\_` outside of pattern-matching contexts, they evaluate to the strings `\%` and `\_`, not to % and _.
\ No newline at end of file
+    4. The `\%` and `\_` sequences are used to search for literal instances of % and _ in pattern-matching contexts where they would otherwise be interpreted as wildcard characters.If you use `\%` or `\_` outside of pattern-matching contexts, they evaluate to the strings `\%` and `\_`, not to % and _.