A.1 MySQL 5.7 FAQ: General
- A.1.1. Which version of MySQL is production-ready (GA)?
- A.1.2. Can MySQL 5.7 do subqueries?
- A.1.3. Can MySQL 5.7 perform multiple-table inserts, updates, and deletes?
- A.1.4. Does MySQL 5.7 have a Query Cache? Does it work on Server, Instance or Database?
- A.1.5. Does MySQL 5.7 have Sequences?
- A.1.6. Does MySQL 5.7 have a NOW() function with fractions of seconds?
- A.1.7. Does MySQL 5.7 work with multi-core processors?
- A.1.8. Why do I see multiple processes for mysqld?
- A.1.9. Can MySQL 5.7 perform ACID transactions?
A.1.1. |
Which version of MySQL is production-ready (GA)? |
MySQL 8.0, 5.7, and MySQL 5.6 are supported for production use. MySQL 8.0 achieved General Availability (GA) status with MySQL 8.0.11, which was released for production use on 19 April 2018. MySQL 5.7 achieved General Availability (GA) status with MySQL 5.7.9, which was released for production use on 21 October 2015. MySQL 5.6 achieved General Availability (GA) status with MySQL 5.6.10, which was released for production use on 5 February 2013. MySQL 5.5 achieved General Availability (GA) status with MySQL 5.5.8, which was released for production use on 3 December 2010. The MySQL 5.5 series is no longer current, but still supported in production. MySQL 5.1 achieved General Availability (GA) status with MySQL 5.1.30, which was released for production use on 14 November 2008. Active development for MySQL 5.1 has ended. MySQL 5.0 achieved General Availability (GA) status with MySQL 5.0.15, which was released for production use on 19 October 2005. Active development for MySQL 5.0 has ended. |
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A.1.2. |
Can MySQL 5.7 do subqueries? |
Yes. See Section 13.2.10, “Subqueries”. |
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A.1.3. |
Can MySQL 5.7 perform multiple-table inserts, updates, and deletes? |
Yes. For the syntax required to perform multiple-table updates, see Section 13.2.11, “UPDATE Statement”; for that required to perform multiple-table deletes, see Section 13.2.2, “DELETE Statement”. A multiple-table insert can be accomplished using a trigger whose |
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A.1.4. |
Does MySQL 5.7 have a Query Cache? Does it work on Server, Instance or Database? |
Yes. (However, the query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0.) The query cache operates on the server level, caching complete result sets matched with the original query string. If an exactly identical query is made (which often happens, particularly in web applications), no parsing or execution is necessary; the result is sent directly from the cache. Various tuning options are available. See Section 8.10.3, “The MySQL Query Cache”. |
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A.1.5. |
Does MySQL 5.7 have Sequences? |
No. However, MySQL has an |
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A.1.6. |
Does MySQL 5.7 have a |
Yes, see Section 11.2.7, “Fractional Seconds in Time Values”. |
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A.1.7. |
Does MySQL 5.7 work with multi-core processors? |
Yes. MySQL is fully multithreaded, and will make use of multiple CPUs, provided that the operating system supports them. |
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A.1.8. |
Why do I see multiple processes for |
When using LinuxThreads, you should see a minimum of three mysqld processes running. These are in fact threads. There is one thread for the LinuxThreads manager, one thread to handle connections, and one thread to handle alarms and signals. |
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A.1.9. |
Can MySQL 5.7 perform ACID transactions? |
Yes. All current MySQL versions support transactions. The The |