@@ -51,7 +51,7 @@ TDengine is a distributed and high performance time series database, there are a
1. Set proper number of `vgroups` according to available CPU cores. Normally, we recommend 2 \* number_of_cores as a starting point. If the verification result shows this is not enough to utilize CPU resources, you can use a higher value.
2. Set proper `minTablesPerVnode`, `tableIncStepPerVnode`, and `maxVgroupsPerDb` according to the number of tables so that tables are distributed even across vgroups. The purpose is to balance the workload among all vnodes so that system resources can be utilized better to get higher performance.
For more performance tuning tips, please refer to [Performance Optimization](../../operation/optimize) and [Configuration Parameters](../../reference/config).
For more performance tuning tips, please refer to [Performance Optimization](../../../operation/optimize) and [Configuration Parameters](../../../reference/config).
-`t`, `T`, `true`, `True`, `TRUE`, `f`, `F`, `false`, and `False` will be handled directly as BOOL types.
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@@ -67,13 +67,13 @@ Schemaless writes process row data according to the following principles.
Note that tag_key1, tag_key2 are not the original order of the tags entered by the user but the result of using the tag names in ascending order of the strings. Therefore, tag_key1 is not the first tag entered in the line protocol.
The string's MD5 hash value "md5_val" is calculated after the ranking is completed. The calculation result is then combined with the string to generate the table name: "t_md5_val". "t*" is a fixed prefix that every table generated by this mapping relationship has.
2. If the super table obtained by parsing the line protocol does not exist, this super table is created.
2. If the super table obtained by parsing the line protocol does not exist, this super table is created(It is not recommended to create a super table manually, otherwise the inserted data may be abnormal).
If the subtable obtained by the parse line protocol does not exist, Schemaless creates the sub-table according to the subtable name determined in steps 1 or 2.
4. If the specified tag or regular column in the data row does not exist, the corresponding tag or regular column is added to the super table (only incremental).
5. If there are some tag columns or regular columns in the super table that are not specified to take values in a data row, then the values of these columns are set to NULL.
6. For BINARY or NCHAR columns, if the length of the value provided in a data row exceeds the column type limit, the maximum length of characters allowed to be stored in the column is automatically increased (only incremented and not decremented) to ensure complete preservation of the data.
7.If the specified data subtable already exists, and the specified tag column takes a value different from the saved value this time, the value in the latest data row overwrites the old tag column take value.
8.Errors encountered throughout the processing will interrupt the writing process and return an error code.
7.Errors encountered throughout the processing will interrupt the writing process and return an error code.
8.In order to improve the efficiency of writing, the order of fields in the same super table should be the same. If the order is different, you need to configure the parameter smlDataFormat to false, otherwise, the data in the library will be abnormal.
:::tip
All processing logic of schemaless will still follow TDengine's underlying restrictions on data structures, such as the total length of each row of data cannot exceed 48k bytes. See [TAOS SQL Boundary Limits](/taos-sql/limit) for specific constraints in this area.
