Merge branch '3.0' of github.com:taosdata/TDengine into szhou/python-udf

docs/en/12-taos-sql/02-database.md

@@ -75,10 +75,10 @@ database_option: {
 - TABLE_PREFIX：The prefix length in the table name that is ignored when distributing table to vnode based on table name.
 - TABLE_SUFFIX：The suffix length in the table name that is ignored when distributing table to vnode based on table name.
 - TSDB_PAGESIZE: The page size of the data storage engine in a vnode. The unit is KB. The default is 4 KB. The range is 1 to 16384, that is, 1 KB to 16 MB.
-- WAL_RETENTION_PERIOD: specifies the time after which WAL files are deleted. This parameter is used for data subscription. Enter a time in seconds. The default value of single copy is 0. A value of 0 indicates that each WAL file is deleted immediately after its contents are written to disk. -1: WAL files are never deleted. The default value of multiple copy is 4 days.
-- WAL_RETENTION_SIZE: specifies the size at which WAL files are deleted. This parameter is used for data subscription. Enter a size in KB. The default value of single copy is 0. A value of 0 indicates that each WAL file is deleted immediately after its contents are written to disk. -1: WAL files are never deleted. The default value of multiple copy is -1.
-- WAL_ROLL_PERIOD: specifies the time after which WAL files are rotated. After this period elapses, a new WAL file is created. The default value of single copy is 0. A value of 0 indicates that a new WAL file is created only after the previous WAL file was written to disk. The default values of multiple copy is 1 day.
-- WAL_SEGMENT_SIZE: specifies the maximum size of a WAL file. After the current WAL file reaches this size, a new WAL file is created. The default value is 0. A value of 0 indicates that a new WAL file is created only after the previous WAL file was written to disk.
+- WAL_RETENTION_PERIOD: specifies the maximum time of which WAL files are to be kept after consumption. This parameter is used for data subscription. Enter a time in seconds. The default value 0. A value of 0 indicates that WAL files are not required to keep after consumption. -1: the time of WAL files to keep has no upper limit.
+- WAL_RETENTION_SIZE: specifies the maximum total size of which WAL files are to be kept after consumption. This parameter is used for data subscription. Enter a size in KB. The default value is 0. A value of 0 indicates that WAL files are not required to keep after consumption. -1: the total size of WAL files to keep has no upper limit.
+- WAL_ROLL_PERIOD: specifies the time after which WAL files are rotated. After this period elapses, a new WAL file is created. The default value is 0. A value of 0 indicates that a new WAL file is created only after TSDB data in memory are flushed to disk.
+- WAL_SEGMENT_SIZE: specifies the maximum size of a WAL file. After the current WAL file reaches this size, a new WAL file is created. The default value is 0. A value of 0 indicates that a new WAL file is created only after TSDB data in memory are flushed to disk.
 
 ### Example Statement
 

docs/zh/12-taos-sql/02-database.md

@@ -75,10 +75,10 @@ database_option: {
 - TABLE_PREFIX：内部存储引擎根据表名分配存储该表数据的 VNODE 时要忽略的前缀的长度。
 - TABLE_SUFFIX：内部存储引擎根据表名分配存储该表数据的 VNODE 时要忽略的后缀的长度。
 - TSDB_PAGESIZE：一个 VNODE 中时序数据存储引擎的页大小，单位为 KB，默认为 4 KB。范围为 1 到 16384，即 1 KB到 16 MB。
-- WAL_RETENTION_PERIOD：wal 文件的额外保留策略，用于数据订阅。wal 的保存时长，单位为 s。单副本默认为 0，即落盘后立即删除。-1 表示不删除。多副本默认为 4 天。
-- WAL_RETENTION_SIZE：wal 文件的额外保留策略，用于数据订阅。wal 的保存的最大上限，单位为 KB。单副本默认为 0，即落盘后立即删除。多副本默认为-1，表示不删除。
-- WAL_ROLL_PERIOD：wal 文件切换时长，单位为 s。当 wal 文件创建并写入后，经过该时间，会自动创建一个新的 wal 文件。单副本默认为 0，即仅在落盘时创建新文件。多副本默认为 1 天。
-- WAL_SEGMENT_SIZE：wal 单个文件大小，单位为 KB。当前写入文件大小超过上限后会自动创建一个新的 wal 文件。默认为 0，即仅在落盘时创建新文件。
+- WAL_RETENTION_PERIOD：数据订阅已消费WAL日志，WAL文件的最大额外保留的时长策略。单位为 s。默认为 0，表示无需额外保留。-1, 表示额外保留，时间无上限。
+- WAL_RETENTION_SIZE：数据订阅已消费WAL日志，WAL文件的最大额外保留的累计大小策略。单位为 KB。默认为 0，表示无需额外保留。-1, 表示额外保留，累计大小无上限。
+- WAL_ROLL_PERIOD：wal 文件切换时长，单位为 s。当WAL文件创建并写入后，经过该时间，会自动创建一个新的WAL文件。默认为 0，即仅在TSDB落盘时创建新文件。
+- WAL_SEGMENT_SIZE：wal 单个文件大小，单位为 KB。当前写入文件大小超过上限后会自动创建一个新的WAL文件。默认为 0，即仅在TSDB落盘时创建新文件。
 
 ### 创建数据库示例
 

docs/zh/14-reference/12-config/index.md

@@ -355,8 +355,6 @@ charset 的有效值是 UTF-8。
 | 取值范围 | 0-4096                      |
 | 缺省值   | CPU 核数的 2 倍                         |
 
-## 时间相关                       |
-
 ## 性能调优
 
 ### numOfCommitThreads