1205 Lock wait timeout exceeded； Try restarting transaction processing

1205 - Lock wait timeout exceeded; try restarting transaction

solve ：

select * from information_schema.innodb_trx; --  Found the read-only transaction that has not been committed  
kill thread id; --  After the corresponding thread 

MySQL 5.5 – innodb_lock_wait lock wait for

before , When there is a ：ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction,
It's a troublesome thing to solve ;
Especially when a SQL performed , But not COMMIT, hinder SQL To execute is to be locked , Timeout end ;
DBA It is impossible to find out the source just from the database SQL lock ;
Sometimes look show engine innodb status , And combine show full processlist; Can solve the problem temporarily ; But it has been unable to accurately locate ;

stay 5.5 in ,information_schema Three tables about locks are added to the library （MEMORY engine ）;

  innodb_trx ##  All currently running transactions 
  innodb_locks ##  The current lock 
  innodb_lock_waits ##  The correspondence of lock waiting 

Take a look at the table structure

desc information_schema .innodb_locks;
  +-------------+---------------------+------+-----+---------+-------+
  | Field | Type | Null | Key | Default | Extra |
  +-------------+---------------------+------+-----+---------+-------+
  | lock_id | varchar(81) | NO | | | |# lock ID
  | lock_trx_id | varchar(18) | NO | | | |# The transaction that owns the lock ID
  | lock_mode | varchar(32) | NO | | | |# The lock mode 
  | lock_type | varchar(32) | NO | | | |# Lock type 
  | lock_table | varchar(1024) | NO | | | |# Locked watch 
  | lock_index | varchar(1024) | YES | | NULL | |# Locked index 
  | lock_space | bigint(21) unsigned | YES | | NULL | |# Locked tablespace number 
  | lock_page | bigint(21) unsigned | YES | | NULL | |# Locked page number 
  | lock_rec | bigint(21) unsigned | YES | | NULL | |# Locked record number 
  | lock_data | varchar(8192) | YES | | NULL | |# Locked data 
  +-------------+---------------------+------+-----+---------+-------+
desc information_schema .innodb_lock_waits;
  +-------------------+-------------+------+-----+---------+-------+
  | Field | Type | Null | Key | Default | Extra |
  +-------------------+-------------+------+-----+---------+-------+
  | requesting_trx_id | varchar(18) | NO | | | |# The transaction requesting the lock ID
  | requested_lock_id | varchar(81) | NO | | | |# A lock that requests a lock ID
  | blocking_trx_id   | varchar(18) | NO | | | |# Transactions that currently have locks ID
  | blocking_lock_id  | varchar(81) | NO | | | |# Locks that currently have locks ID
  +-------------------+-------------+------+-----+---------+-------+
desc information_schema .innodb_trx ;
  +----------------------------+---------------------+------+-----+---------------------+-------+
  | Field | Type | Null | Key | Default | Extra |
  +----------------------------+---------------------+------+-----+---------------------+-------+
  | trx_id | varchar(18) | NO | | | |# Business ID
  | trx_state | varchar(13) | NO | | | |# State of affairs ：
  | trx_started | datetime | NO | | 0000-00-00 00:00:00 | |# Transaction start time ;
  | trx_requested_lock_id | varchar(81) | YES | | NULL | |#innodb_locks.lock_id
  | trx_wait_started | datetime | YES | | NULL | |# The time when the transaction starts to wait 
  | trx_weight | bigint(21) unsigned | NO | | 0 | |#
  | trx_mysql_thread_id | bigint(21) unsigned | NO | | 0 | |# Transaction thread ID
  | trx_query | varchar(1024) | YES | | NULL | |# Specifically SQL sentence 
  | trx_operation_state | varchar(64) | YES | | NULL | |# The current operation state of the transaction 
  | trx_tables_in_use | bigint(21) unsigned | NO | | 0 | |# How many tables are used in the transaction 
  | trx_tables_locked | bigint(21) unsigned | NO | | 0 | |# How many locks does the transaction have 
  | trx_lock_structs | bigint(21) unsigned | NO | | 0 | |#
  | trx_lock_memory_bytes | bigint(21) unsigned | NO | | 0 | |# Transaction locked memory size （B）
  | trx_rows_locked | bigint(21) unsigned | NO | | 0 | |# Number of rows locked in transaction 
  | trx_rows_modified | bigint(21) unsigned | NO | | 0 | |# Number of rows changed by transaction 
  | trx_concurrency_tickets | bigint(21) unsigned | NO | | 0 | |# Number of transactions and invoices 
  | trx_isolation_level | varchar(16) | NO | | | |# Transaction isolation level 
  | trx_unique_checks | int(1) | NO | | 0 | |# Is the uniqueness check 
  | trx_foreign_key_checks | int(1) | NO | | 0 | |# Whether foreign key check 
  | trx_last_foreign_key_error | varchar(256) | YES | | NULL | |# Last foreign key error 
  | trx_adaptive_hash_latched | int(1) | NO | | 0 | |#
  | trx_adaptive_hash_timeout | bigint(21) unsigned | NO | | 0 | |#
  +----------------------------+---------------------+------+-----+---------------------+-------
select * from information_schema.innodb_lock_waits G