Detailed interpretation of distributed | dble release notes


Dble is coming, global table function reset!!!

With the resumption of work in all walks of life after the festival, dble 2.19.11 is also released today, unexpectedly!

The following is a detailed interpretation of dble release notes. The article is mainly divided into the following four parts:

  • 1、 Introduction to dble project
  • 2、 Overview of the new version
  • 2、 Main update interpretation
  • 3、 Complete release notes

1、 Introduction to dble project

DBLE — Enterprise level open source distributed middlewareThe nickname “MYCAT plus” was given by the people in the rivers and lakes. With its simple and stable, continuous maintenance, good community environment and broad mass base, it has been strongly supported by the community.

Dble official project:    
		If you are interested in source code or need customized functions, you can install it through source code compilation

		Dble official document (Updated)    
		You can learn more about the background and application scenarios of dble. Details not covered in this article can be obtained in official documents

		Download address and release notes of the new version of dble:

Official courses

Click to learn “dble fast start” practical video + text draft!

Click to learn the advanced course of dble open course

Tips: it is recommended to download the latest releases version, and the tar package can be downloaded. If there is a need for source code compilation, you can download the source code package.

2、 Overview of the new version

90 days after the release of, version was released; 13 refactoring functions, 28 defects and 2 backward compatibility adjustments were added in the new version of dble;

Thank you first

  • Thanks to GitHub users for the quality issue

3、 Main update interpretation

The main feature of this version update is the global table checking method [ාාාාාාාාාාාාාාා

1. Introduction to global table checking

Global table is a special type of table in dble_ A on all distributed nodes, table_ A because the following two conditions are met simultaneously:

  • Have the same table structure
  • Have the same table data

But in fact, in the running process of the system and dble, some unavoidable errors in distributed transactions may lead to the tables on different nodes after a long run_ A the data above is inconsistent.

In order to find the problem in time and not cause further errors, dble uses the method of regularly checking table data_ Check the data consistency in a, and inform the operation and maintenance personnel of the results of the inspection.

2. Support the development and use of custom global table checking

Please refer to the official Manual:

Manual address:…

4、 Complete release notes

We have released a new version
Firstly, we must thanks to the following people for their contributions to our community:
@Lordess, @zhaoshan86, @liuxinwang,@ssxlulu

Release Notes:


  • [#1607] Change the default value of bufferPoolPageNumber
  • [#1585] Add filter condition for some manager command
  • [#1575] add an manager command to show recently(doing or done) query detail stage
  • [#1566] Add command show @@data_distribution to show data distribution for table
  • [#1564] Add STAGE for show @@connection.sql
  • [#1558] Remove old global table check. Add new general global table check & allow customization for global table check
  • [#1544] Heartbeat can check if backend is read_only
  • [#1543] Add propery autocommit to DBLE’s server.xml
  • [#1539] strength usage of view, support MySQL view for vertical sharding
  • [#1527] Add new command show @@Questions
  • [#1526] Change primaryKey into cacheKey in schema.xml
  • [#1521] Support dump file without create table stmt when splitting dump file
  • [#1362] Support kill query statement

For more details, please read the document.


  • [#1532] LOAD DATA INFILE doesn’t encode data before sending it to MySQL when dealing with a small data file, thanks @Lordess report the bug.
  • [#1489] Complex query using one view in another view will get an error column not found
  • [#275] Result set is not merged because of union query on different global tables
  • [#563] Incorrect result when natural join on the global table
  • [#622] Illegal “create table ” syntax execute success for global table
  • [#775] Query [load data …] to global table, column _dble_op_time may need special handle
  • [#1582] DataHost’s heartbeat attribute is not synced after reload @@config_all in ZooKeeper mode
  • [#1451] SQL select a as b from table group by a returns error when b is one of the table’s columns names
  • [#1513] Commit XA transaction will return ‘lost connection’ error when killed one of the backend connection before XA end phase
  • [#1638] Restart mysql node causing the error: the data source[XXX] can’t reach. Please check the dataHost status
  • [#1538] Change dataHost from disabled to enabled, the heartbeat does not recover
  • [#1622] Memory Leak in Some cases
  • [#1524] DDL separate from general queries
  • [#1525] Syntax ‘limit 0’ will return all rows, thanks @ssxlulu report the bug.
  • [#1453] Use user variables in [order by] with union got error
  • [#1618] Compound SQL statement returned package error
  • [#1583] Use DBLE as DBLE’s backend, thanks @zhaoshan86 report the bug.
  • [#1643] Execute query “show warnings” causing an error : Lost connection to MySQL server during query
  • [#1465] Schema.xml datanode sums of attributes values of name and database should equal
  • [#1602] Explain a query with an uppercase table alias when [lower_case_tables_name=1], it will report error
  • [#1541] If there are too many datanodes(>700) for a few dozen datahost, starting/reloading will become slow because of testConn
  • [#1507] Load data returns an error when there is a separate line “” in file
  • [#1466] [select from test join sharding_2_t1 b on>1.001] result not consistent with mysql
  • [#1459] Global sequence does not work correctly for the no-sharding table, thanks @liuxinwang report the bug.
  • [#1455] Query [SELECT * FROM t1 a left join t2 c on and [email protected]_a;] report field not found:@id_a
  • [#1417] The column type returned by DBLE is inconsistent with the MYSQL database.
  • [#1403] Packet ID error for LOAD DATA multi-Queries
  • [#753] dble does not support reserved words as table name or column name even use backtick

Breaking backward compatibility:

  • [#1558] Remove old global table check. Add new general global table check & allow customization for global table check
  • [#1526] Change primaryKey into cacheKey in schema.xml