MySQL英文文献及翻译 第3页
原文：Understanding MySQL Internals
MySQL architecture is best understood in the context of its history. Thus, the two are discussed in the same chapter.
MySQL History
MySQL history goes back to 1979 when Monty Widenius, working for a small companycalled TcX, created a reporting tool written in BASIC that ran on a 4 Mhzcomputer with 16 KB RAM. Over time, the tool was rewritten in C and ported to run on Unix. It was still just a low-level storage engine with a reporting front end. The tool was known by the name of Unireg.
Working under the adverse conditions of little computational resources, and perhaps building on his God-given talent,Monty developed a habit and ability to write very efficient code naturally. He also developed, or perhaps was gifted from the start,with an unusually acute vision of what needed to be done to the code to make it useful in future development—without knowing in advance much detail about what that future development would be.
In addition to the above, with TcX being a very small company and Monty being one of the owners, he had a lot of say in what happened to his code. While there are perhaps a good number of programmers out there with Monty’s talent and ability, for a number of reasons, few get to carry their code around for more than 20 years. Monty did.
Monty’s work, talents, and ownership of the code provided a foundation upon which the Miracle of MySQL could be built.
Some time in the 1990s, TcX customers began to push for an SQL interface to their data. Several possibilities were considered. One was to load it into a commercial database.Monty was not satisfied with the speed. He tried borrowing mSQL code for the SQL part and integrating it with his low-level storage engine. That did not work well,either. Then came the classic move of a talented,driven programmer: “I’ve had enough of those tools that somebody else wrote that don’t work! I’m writing my own!”
Thus in May of 1996 MySQL version 1.0 was released to a limited group, followed by a public release in October 1996 of version 3.11.1. The initial public release provided only a binary distribution for Solaris. A month later, the source and the Linux binary were released.
In the next two years, MySQL was ported to a number of other operating systems as the feature set gradually increased. MySQL was originally released under a special license that allowed commercial use to those who were not redistributing it with their software. Special licenses were available for sale to those who wanted to bundle it with their product. Additionally, commercial support was also being sold. This provided TcX with some revenue to justify the further development of MySQL,although 毕业论文
http://www.751com.cn could possibly be written by one person, was extremely fast, and was very stable.Numerous APIs were contributed, so one could write a client in pretty much any existing programming language. However, it still lacked support for transactions,subqueries, foreign keys, stored procedures, and views. The locking happened only at a table level, which in some cases could slow it down to a grinding halt. Some programmers unable to get around its limitations still considered it a toy, while others were more than happy to dump their Oracle or SQL Server in favor of MySQL, and deal with the limitations in their code in exchange for improvement in performance and licensing cost savings.
Around 1999–2000 a separate company named MySQL AB was established. It hired several developers and established a partnership with Sleepycat to provide an SQL interface for the Berkeley DB data files. Since Berkeley DB had transaction capabilities,this would give MySQL support for transactions, which it previously lacked.After some changes in the code in preparation for integrating Berkeley DB,version 3.23 was released.
Although the MySQL 无耻悲鄙下流的网.学,网总是抄辣|文,论-文.网,本网不再提供完整内容.source became equipped with hooks to add any type of storage engine, including a transactional one.
By April of 2000, with some encouragement and sponsorship from Slashdot, masterslave replication capability was added. The old nontransactional storage engine,ISAM, was reworked and released as MyISAM. Among a number of improvements,full-text search capabilities were now supported. A short-lived partnership with NuSphere to add Gemini, a transactional engine with row-level locking, ended in a lawsuit toward the end of 2001. However, around the same time, Heikki Tuuri approached MySQL AB with a proposal to integrate his own storage engine,InnoDB, which was also capable of transactions and row-level locking.
Heikki’s contribution integrated much more smoothly with the new table handler interface already polished off by the Berkeley DB integration efforts. The MySQL/InnoDB combination became version 4.0, and was released as alpha in October of 2001. By early 2002 the MySQL/InnoDB combo was stable and instantly took MySQL to another level. Version 4.0 was finally declared production stable in March 2003.
It might be worthy of mention that the version number change was not caused by the addition of InnoDB. MySQL developers have always viewed InnoDB as an important addition, but by no means something that they
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