Detailed description of Mysql Proxy Lua internal struct and variables

Mysql Proxy LuaInternalStructureBody andVariableIs the content to be introduced in this article, mainly to learnMysql ProxyOfStructureBody andVariableFor more information, see this article.

Mysql ProxyOfLUAMany internal structures can be used in the configuration script. The most important one is proxy. proxy provides many other struct interfaces, such as the connection list and backend server list. Structures from customers such as incoming packet only exist in the context of script functions.

Attribute description:

 
 

  
  
Connection: contains the connection proxy. connection list of all active customers ..
  
  
Servers: List of backend servers proxy. backends)
  
  
Queries: the query that a customer wants to send to the server
  
  
PROXY_VERSION: Mysql Proxy version, in hexadecimal format.
 
 

Proxy. connection

Proxy. connection is a read-only object that provides information about the current active connection.

Proxy. connection attributes:

Thread_id: Connection threadid

Backend_ndx: ID of the backend server corresponding to the current connection

Proxy. backends

The proxy. backends part is writable and contains a list of background server and server meta information. You can specify the backend server used by the current connection.

Proxy. backends attributes:

Address: Host Name/Port Combination of the current connection

Connected_clients: number of connected customers

State: the status of the backend server.

Proxy. queries

Proxy. queries is a query queue to be sent to the server,

 
 

  
  
The queue is not populated automatically, but if you do not explicitly populate the queue then queries are 
  
  
 passed on to the backend server verbatim. Also, if you do not populate the query queue by hand, 
  
  
 then the read_query_result() function is not triggered. 
  
  
The following methods are supported for populating the proxy.queries object.  
 
 

Function Description:

 
 

  
  
Append (id, packet) is added to the end of the team.
  
  
Prepend (id, packet) inserts the queue header.
  
  
Len () returns the length of the queried queue
 
 

The following constant Mysql Proxy is used to specify the operation:

 
 

  
  
PROXY_SEND_QUERY is sent to the server.
  
  
PROXY_SEND_RESULT: return the client Query Result
  
  
PROXY_IGNORE_RESULT discard result set
 
 

Package status constant: 

 
 

  
  
MYSQLD_PACKET_OK The packet is OK.   
  
  
MYSQLD_PACKET_ERR The packet contains error information.   
  
  
MYSQLD_PACKET_RAW The packet contains raw data.  
 
 

Constant background status:

 
 

  
  
BACKEND_STATE_UNKNOWN The current status is unknown.
  
  
BACKEND_STATE_UP The backend is known to be up (available ).
  
  
BACKEND_STATE_DOWN The backend is known to be down (unavailable ).
  
  
BACKEND_TYPE_UNKNOWN Backend type is unknown.
  
  
BACKEND_TYPE_RW Backend is available for read/write.
  
  
BACKEND_TYPE_RO Backend is available only for read-only use.
  
  
 
  
  
Server command constant:
  
  
 
  
  
Constant Description
  
  
COM_SLEEP Sleep
  
  
COM_QUIT Quit
  
  
COM_INIT_DB Initialize database
  
  
COM_QUERY Query
  
  
COM_FIELD_LIST Field List
  
  
COM_CREATE_DB Create database
  
  
COM_DROP_DB Drop database
  
  
COM_REFRESH Refresh
  
  
COM_SHUTDOWN Shutdown
  
  
COM_STATISTICS Statistics
  
  
COM_PROCESS_INFO Process List
  
  
COM_CONNECT Connect
  
  
COM_PROCESS_KILL Kill
  
  
COM_DEBUG Debug
  
  
COM_PING Ping
  
  
COM_TIME Time
  
  
COM_DELAYED_INSERT Delayed insert
  
  
COM_CHANGE_USER Change user
  
  
COM_BINLOG_DUMP Binlog dump
  
  
COM_TABLE_DUMP Table dump
  
  
COM_CONNECT_OUT Connect out
  
  
COM_REGISTER_SLAVE Register slave
  
  
COM_STMT_PREPARE Prepare server-side statement
  
  
COM_STMT_EXECUTE Execute server-side statement
  
  
COM_STMT_SEND_LONG_DATA Long data
  
  
COM_STMT_CLOSE Close server-side statement
  
  
COM_STMT_RESET Reset statement
  
  
COM_SET_OPTION Set option
  
  
COM_STMT_FETCH Fetch statement
  
  
COM_DAEMON Daemon (MySQL 5.1 only)
  
  
COM_ERROR Error
 
 

MySQL Data Type

 
 

  
  
Constant Field Type   
  
  
MYSQL_TYPE_DECIMAL Decimal   
  
  
MYSQL_TYPE_NEWDECIMAL Decimal (MySQL 5.0 or later)   
  
  
MYSQL_TYPE_TINY Tiny   
  
  
MYSQL_TYPE_SHORT Short   
  
  
MYSQL_TYPE_LONG Long   
  
  
MYSQL_TYPE_FLOAT Float   
  
  
MYSQL_TYPE_DOUBLE Double   
  
  
MYSQL_TYPE_NULL Null   
  
  
MYSQL_TYPE_TIMESTAMP Timestamp   
  
  
MYSQL_TYPE_LONGLONG Long long   
  
  
MYSQL_TYPE_INT24 Integer   
  
  
MYSQL_TYPE_DATE Date   
  
  
MYSQL_TYPE_TIME Time   
  
  
MYSQL_TYPE_DATETIME Datetime   
  
  
MYSQL_TYPE_YEAR Year   
  
  
MYSQL_TYPE_NEWDATE Date (MySQL 5.0 or later)   
  
  
MYSQL_TYPE_ENUM Enumeration   
  
  
MYSQL_TYPE_SET Set   
  
  
MYSQL_TYPE_TINY_BLOB Tiny Blob   
  
  
MYSQL_TYPE_MEDIUM_BLOB Medium Blob   
  
  
MYSQL_TYPE_LONG_BLOB Long Blob   
  
  
MYSQL_TYPE_BLOB Blob   
  
  
MYSQL_TYPE_VAR_STRING Varstring   
  
  
MYSQL_TYPE_STRING String   
  
  
MYSQL_TYPE_TINY Tiny (compatible with MYSQL_TYPE_CHAR)    
  
  
MYSQL_TYPE_ENUM Enumeration (compatible with MYSQL_TYPE_INTERVAL)   
  
  
MYSQL_TYPE_GEOMETRY Geometry   
  
  
MYSQL_TYPE_BIT Bit   
 
 

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