tencent cloud

PrevNext

Feedback

search by keyword

Recent Pages

Documentation
Tencent Cloud TCHouse-D
    Documentation
    Download PDF

    Naming Specifications and Limits to the Database and Data Table

    Last updated: 2024-07-31 09:17:12
    Download PDF
      This document will introduce the naming specifications and some limitations for creating and changing databases and tables in Tencent Cloud TCHouse-D.

      Naming Specifications

      Database

      Name: The table name must start with a letter or an underscore. It can contain letters, numbers, and underscores, with a length of 1 to 64 characters.
      Description: It can contain up to 2,048 characters.
      Limitations: The same data link cannot have identical database names.

      Data Table/View

      Name: The table name must start with a letter or an underscore. It can contain letters, numbers, and underscores, with a length of 1 to 64 characters.
      Description: It can contain up to 2,048 characters.
      Limitations: The same database cannot have identical data table names.

      Attribute Column

      Name: The column name must start with a letter or an underscore. It can contain letters, numbers, and underscores, with a length of 1 to 256 characters.
      Description: It can contain up to 256 characters.
      Limitations: The same data table cannot have identical data column names.

      Partition

      Partition feld name: Length should be 1 to 256 characters.
      Usage recommendations:
      1. When the single table data volume is below 200 million records, for convenience, you can choose not to set partitions and use bucketing instead;
      2. When the partition field has a continuous data range (such as date and ID), it is recommended to choose Range partition;
      3. When the data has discrete values (such as country, region, and status), it is recommended to choose LIST partition.

      Bucketing

      Bucket field name: Length should be 1 to 256 characters
      Usage recommendations:
      1. The bucket key can be one or multiple; multiple keys ensure a more balanced data distribution, while a single key is easier to match.
      2. Selection of bucket columns: generally choose fields with high differentiation/cardinality and even hash to avoid data skew; they should also be frequently used fields to improve query efficiency;
      3. The number of buckets created should not be too many or too few; it is recommended to keep each bucket between 1-10 GB.

      Use Limits

      Quantity Limit of Database/Table/Column/Partition

      Restriction Item
      Quantity Limit
      Number of catalogs that can be created
      20
      Number of databases per cluster
      10,000
      Number of databases per user
      1,000
      Number of data tables per cluster
      100,000
      Number of data tables per user
      10,000
      Number of data tables per database
      4,096
      Number of fields per table
      2,048
      Number of partitions per table
      10,000
      Number of views per cluster
      10,000
      Maximum view nesting level
      10
      Number of materialized views per cluster
      10,000

      Query Limits

      Restriction Item
      Explanation
      Supplement
      Daily data query volume
      No limit
      -
      Number of tables in a single SQL query
      32
      -
      Single SQL query timeout
      900 seconds
      -
      Maximum number of files per external table
      No limit
      -

      DML/DML Limits

      Restriction Item
      Explanation
      Supplement
      Simultaneous schema changes per cluster
      20
      -
      Simultaneous schema changes per table
      1
      -
      Data write concurrency per table (per second)
      10
      High-frequency writes are not recommended; it is advised to batch write appropriately: the total number of imports per table should not exceed 20 times per minute.
      Data write concurrency for the same key per table (per second)
      1
      The same key in one table cannot be updated simultaneously; otherwise, it may cause data inaccuracy.
      
      Contact Us

      Contact our sales team or business advisors to help your business.

      Contact Us
      Technical Support

      Open a ticket if you're looking for further assistance. Our Ticket is 7x24 avaliable.

      Submit a Ticket
      7x24 Phone Support
      Copyright © 2013-2024 Tencent Cloud. All Rights Reserved.
      Privacy PolicyLegalCookie Policy