Common DBLE Operational Commands for Monitoring, Diagnosis, and Maintenance

DBLE is a widely used open‑source MySQL distributed middleware that offers two ports: the default business port 8066 and the management port 9066, both configurable in conf/bootstrap.cnf. User definitions (managerUser, shardingUser, rwSplitUser) are stored in conf/user.xml.

Basic Information Commands show @@help – lists all available management commands. show @@server – displays memory usage, uptime, and character set. show @@database – shows configured logical databases. show @@shardingNode – reveals logical sharding node details. show @@sql and show @@sql.high – list recent SQL statements and high‑frequency/slow queries. show @@sql.sum.user, show @@sql.sum.table – summarize read/write counts by user or table. show @@sysparam – shows DBLE configuration parameters. show @@white – displays whitelist settings. show @@binlog.status – reports GTID execution status of backend instances. show @@algorithm where schema='testdb' and table='sbtest1' – checks the sharding algorithm for a specific table.

show @@shardingNodes where schema='testdb' and table='sbtest1'

– lists logical sharding nodes for a table. show @@reload_status – shows the reload count of configuration files. show @@user and show @@user.privilege – list users and their privileges. show @@data_distribution where table='testdb.sbtest1' – shows row distribution of a sharded table. show @@connection_pool – displays connection pool settings for backend instances. file @@list, file @@show filename, file @@upload filename content – (deprecated after 3.21.06) manage files in the conf directory.

Fault Diagnosis Commands show @@heartbeat – checks heartbeat status of backend databases. show @@backend – shows connections from DBLE to backend instances. show @@connection – lists active frontend connections and network traffic. show @@connection.sql – displays SQL received on each frontend connection. show @@session – shows active backend sessions. show @@thread_used – reports internal thread load, with details such as BussinessExecutorX, backendBusinessExecutorX, _NIO_REACTOR_FRONT_X, and _NIO_REACTOR_BACKEND_X, configurable via bootstrap.cnf. enable @@general_log – turns on DBLE general log for capturing SQL statements (use with caution due to overhead).

Maintenance Operations kill @@connection – terminates a client connection using the FRONT_ID from show @@connection. reload @@config_all – reloads all configuration files without stopping DBLE. dryrun – validates configuration files for potential issues. check full @@metadata – verifies table definition consistency (not real‑time). check @@global – checks global table consistency across shards.

split src dest [-sschema] [-r500] [-w500] [-l10000] [--ignore] [-t2]

– splits a large table into multiple SQL files for parallel import. pause @@shardingNode = 'dn1' and timeout = 10000; – pauses traffic to a sharding node during scaling; resume restores traffic. reload @@config_all (used after pause) – applies the new configuration.

These commands together form a practical toolbox for DBLE administrators to monitor performance, diagnose issues, and safely perform maintenance on distributed MySQL clusters.