Innodb_lock_wait_timeout mysql

What is innodb_lock_wait_timeout ? In MySql innodb_lock_wait_timeout is an Innodb transaction wait time in seconds for a row lock. An another transaction has to wait for specified innodb_lock_wait_timeout if a transaction is taking place.

1. What is Innodb_sort_buffer_size MySQL?
2. What is innodb_log_file_size MySQL?
3. What is Innodb_stats_persistent_sample_pages?
4. What is the use of innodb_buffer_pool_size?
5. What is Innodb_log_files_in_group?
6. What Causes lock wait timeout MySQL?
7. What Causes lock wait timeout?
8. How do I stop a MySQL table from locking?
9. What is Innodb_adaptive_hash_index?
10. How do I show global variables in MySQL?
11. What is Tmp_table_size in MySQL?
12. What is Table_open_cache in MySQL?
13. What is Query_cache_type in MySQL?
14. What is Innodb_thread_concurrency in MySQL?

What is Innodb_sort_buffer_size MySQL?

innodb_sort_buffer_size specifies the size of sort buffers used for sorting data during creation of an InnoDB index. While sort_buffer_size is just a per-connection variable and do not belongs to any specific storage engine.

What is innodb_log_file_size MySQL?

innodb_log_file_size. This parameter determines the fixed size for MySQL's redo logs. Tuning this value affects the crash recovery time and also overall system performance. The default value is 134,217,728 (about 128 MB). The default value for innodb_log_file_size might be small for your workload.

What is Innodb_stats_persistent_sample_pages?

innodb_stats_persistent_sample_pages. It is used for number of index pages to sample when estimating cardinality and other statistics for an indexed column.

What is the use of innodb_buffer_pool_size?

innodb_buffer_pool_size is the MySQL configuration parameter that specifies the amount of memory allocated to the InnoDB buffer pool by MySQL. This is one of the most important settings in the MySQL hosting configuration and should be configured based on the available system RAM.

What is Innodb_log_files_in_group?

innodb_buffer_pool_size is the amount of memory to use to cache tables, indexes and a few other things. This is the main tunable and you will want to set it quite high for performance reasons - there are plenty of resources discussing this.

What Causes lock wait timeout MySQL?

The common causes are: The offensive transaction is not fast enough to commit or rollback the transaction within innodb_lock_wait_timeout duration. The offensive transaction is waiting for row lock to be released by another transaction.

What Causes lock wait timeout?

A lock wait timeout results when one user gets a lock on some data and holds it while another user tries to access it. If the first user doesn't unlock the data, the second one will time out after a while. ... For example, the first user and second user both lock some data.

How do I stop a MySQL table from locking?

Option 3: Third option to prevent table locks with MySQL database is to use AUTOCOMMIT on the database level. This will prevent table locks from occurring unintentionally during report execution since all the transactions are committed after they are executed without additional commit commands.

What is Innodb_adaptive_hash_index?

The adaptive hash index is enabled by the innodb_adaptive_hash_index variable, or turned off at server startup by --skip-innodb-adaptive-hash-index . Based on the observed pattern of searches, a hash index is built using a prefix of the index key. ... InnoDB has a mechanism that monitors index searches.

How do I show global variables in MySQL?

SHOW VARIABLES accepts an optional GLOBAL or SESSION variable scope modifier: With a GLOBAL modifier, the statement displays global system variable values. These are the values used to initialize the corresponding session variables for new connections to MySQL. If a variable has no global value, no value is displayed.

What is Tmp_table_size in MySQL?

LEAST(max_heap_table_size, tmp_table_size) is the cap on how big to let certain implicit temp tables to get. These are tables used inside SELECTs (etc) to handle GROUP BY , ORDER BY , subqueries, etc.

What is Table_open_cache in MySQL?

table_open_cache indicates the maximum number of tables the server can keep open in any one table cache instance. Ideally, you'd like this set so as to re-open a table as infrequently as possible.

What is Query_cache_type in MySQL?

MySQL determines the queries to cache by examining the query_cache_type variable. Setting this value to 0 or OFF prevents caching or retrieval of cached queries. You can also set it to 1 to enable caching for all queries except for ones beginning with the SELECT SQL_NO_CACHE statement.

What is Innodb_thread_concurrency in MySQL?

By default, innodb_thread_concurrency is 0. That's actually the best setting. It means infinite concurrency. It allows the InnoDB storage engine to decide the best number of concurrency tickets to launch and address. Setting it to a nonzero value actually can throttle InnoDB or throttle the OS if not set properly.