Innodb

Trx_rseg_history_len

Trx_rseg_history_len
  1. What is HLL MySQL?
  2. What is InnoDB history length?
  3. How does InnoDB check engine status?
  4. Why is the RDS so slow?
  5. How do I improve my AWS RDS performance?
  6. What is InnoDB engine?
  7. How do I stop a process in MySQL?
  8. What is Innodb_thread_concurrency in MySQL?
  9. What is InnoDB buffer pool?
  10. How do I know what MySQL engine I have?
  11. How do MySQL transactions work?
  12. How do I COMMIT in phpmyadmin?
  13. Are transactions supported by MySQL?

What is HLL MySQL?

The InnoDB history list length represents the number of unflushed changes. If your workload demands a lot of long running or open transactions, then you can expect to see a high HLL on the database.

What is InnoDB history length?

To understand these terms, you have to understand a lot of the foundations of InnoDB. In layman's terms, to be a bit hand-wavy, the history list length is in units of changes. If you're a Git user, you might think of it as analogous to the commit history of the database.

How does InnoDB check engine status?

SHOW ENGINE INNODB STATUS is a specific form of the SHOW ENGINE statement that displays the InnoDB Monitor output, which is extensive InnoDB information which can be useful in diagnosing problems.

Why is the RDS so slow?

RDS is not slow. It may be marginally slower compared to your local mysql server since RDS is a remote instance. If you see it performing way too slow, then chances are that your RDS instance is running in a different availability zone than your EC2 instances.

How do I improve my AWS RDS performance?

An Amazon RDS performance best practice is to allocate enough RAM so that your working set resides almost completely in memory. The working set is the data and indexes that are frequently in use on your instance. The more you use the DB instance, the more the working set will grow.

What is InnoDB engine?

InnoDB is a storage engine for the database management system MySQL and MariaDB. Since the release of MySQL 5.5. 5 in 2010, it replaced MyISAM as MySQL's default table type. It provides the standard ACID-compliant transaction features, along with foreign key support (Declarative Referential Integrity).

How do I stop a process in MySQL?

Login to DB; Run a command show full processlist; to get the process id with status and query itself which causes the database hanging; Select the process id and run a command KILL <pid>; to kill that process.

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.

What is InnoDB buffer pool?

The buffer pool is an area in main memory where InnoDB caches table and index data as it is accessed. The buffer pool permits frequently used data to be accessed directly from memory, which speeds up processing. On dedicated servers, up to 80% of physical memory is often assigned to the buffer pool.

How do I know what MySQL engine I have?

If you're using MySQL Workbench, right-click a table and select alter table . In that window you can see your table Engine and also change it.

How do MySQL transactions work?

Transactions are atomic units of work that can be committed or rolled back. When a transaction makes multiple changes to the database, either all the changes succeed when the transaction is committed, or all the changes are undone when the transaction is rolled back.

How do I COMMIT in phpmyadmin?

begin; INSERT INTO tbl_setting (setting_name) VALUES ('test'); commit; While browsing from phpmyadmin, it is showing the desired result; But in command mode of Windows 8, with query SELECT * FROM tbl_setting it is not displaying the row I just inserted.

Are transactions supported by MySQL?

MySQL supports local transactions (within a given client session) through statements such as SET autocommit , START TRANSACTION , COMMIT , and ROLLBACK . 1, “START TRANSACTION, COMMIT, and ROLLBACK Statements”. ...

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