Category: MySQLDevelopment

MySQL Internals Files In MySQL Sources

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Contents

[edit] MySQL Source Code Distribution

This is a description of the files that you get when you download the source code of MySQL. This description begins with a list of the main directories and a short comment about each one. Then, for each directory, in alphabetical order, a longer description is supplied. When a directory contains significant program files, a list of each C program is given along with an explanation of its intended function.

[edit] Directory Listing

Directory Short Comment

[edit] The bdb Directory

The Berkeley Database table handler.

The Berkeley Database (BDB) is maintained by Sleepycat Software. MySQL AB maintains only a few small patches to make BDB work better with MySQL.

The documentation for BDB is available at http://www.sleepycat.com/docs/. Since it's reasonably thorough documentation, a description of the BDB program files is not included in this document.

[edit] The BitKeeper Directory

BitKeeper administration.

Bitkeeper administration is not part of the source distribution. This directory may be present if you downloaded the MySQL source using BitKeeper rather than via the mysql.com site. The files in the BitKeeper directory are for maintenance purposes only they are not part of the MySQL package.

The MySQL Reference Manual explains how to use Bitkeeper to get the MySQL source. Please see http://www.mysql.com/doc/en/installing-source-tree.html. for more information.

[edit] The BUILD Directory

Frequently used build scripts.

This directory contains the build switches for compilation on various platforms. There is a subdirectory for each set of options. The main ones are:

[edit] The client Directory

Client library.

The client library includes mysql.cc (the source of the mysql executable) and other utilities. Most of the utilities are mentioned in the MySQL Reference Manual. Generally these are standalone C programs which one runs in "client mode", that is, they call the server.

The C program files in the directory are:

[edit] The config Directory

Macros for use during build.

There is a single subdirectory: \ac-macros. All the files in it have the extension .m4, which is a normal expectation of the GNU autoconf tool.

[edit] The cmd-line-utils Directory

Command-line utilities (libedit and readline).

There are two subdirectories: \readline and \libedit. All the files here are "non-MySQL" files, in the sense that MySQL AB didn't produce them, it just uses them. It should be unnecessary to study the programs in these files unless you are writing or debugging a tty-like client for MySQL, such as mysql.exe.

The \readline subdirectory contains the files of the GNU Readline Library, "a library for reading lines of text with interactive input and history editing". The programs are copyrighted by the Free Software Foundation.

The \libedit (library of edit functions) subdirectory has files written by Christos Zoulas. They are distributed and modifed under the BSD License. These files are for editing the line contents.

These are the program files in the \libedit subdirectory:

[edit] The dbug Directory

Fred Fish's dbug library.

This is not really part of the MySQL package. Rather, it's a set of public-domain routines which are useful for debugging MySQL programs. The MySQL Server and all .c and .cc programs support the use of this package.

How it works: One inserts a function call that begins with DBUG_* in one of the regular MYSQL programs. For example, in get_password.c, you will find this line: 

DBUG_ENTER("get_tty_password");

at the start of a routine, and this line: 

DBUG_RETURN(my_strdup(to,MYF(MY_FAE)));

at the end of the routine. These lines don't affect production code. Features of the dbug library include extensive reporting and profiling (the latter has not been used by the MySQL team).

The C programs in this directory are:

[edit] The Docs Directory

With the BitKeeper downloads, /Docs is nearly empty. Binary and source distributions include some pre-formatted documentation files, such as the MySQL Reference manual in Info format (for Unix) or CHM format (for Windows).

[edit] The extra Directory

Some minor standalone utility programs.

These programs are all standalone utilities, that is, they have a main() function and their main role is to show information that the MySQL server needs or produces. Most are unimportant. They are as follows:

[edit] The heap Directory

The HEAP (MEMORY) table handler.

All the MySQL table handlers (i.e. the handlers that MySQL itself produces) have files with similar names and functions. Thus, this (heap) directory contains a lot of duplication of the myisam directory (for the MyISAM table handler). Such duplicates have been marked with an "*" in the following list. For example, you will find that \heap\hp_extra.c has a close equivalent in the myisam directory (\myisam\mi_extra.c) with the same descriptive comment. (Some of the differences arise because HEAP has different structures. HEAP does not need to use the sort of B-tree indexing that ISAM and MyISAM use; instead there is a hash index. Most importantly, HEAP is entirely in memory. File-I/O routines lose some of their vitality in such a context.)

There are fewer files in the heap directory than in the myisam directory, because fewer are necessary. For example, there is no need for a \myisam\mi_cache.c equivalent (to cache reads) or a \myisam\mi_log.c equivalent (to log statements).

[edit] The include Directory

Header (*.h) files for most libraries; includes all header files distributed with the MySQL binary distribution.

These files may be included in C program files. Note that each individual directory will also have its own *.h files, for including in its own *.c programs. The *.h files in the include directory are ones that might be included from more than one place.

For example, the mysys directory contains a C file named rijndael.c, but does not include rijndael.h. The include directory contains rijndael.h. Looking further, you'll find that rijndael.h is also included in other places: by my_aes.c and my_aes.h.

The include directory contains 55 *.h (header) files.

[edit] The innobase Directory

The Innobase (InnoDB) table handler.

A full description of these files can be found elsewhere in this document.

[edit] The libmysql Directory

The MySQL Library, Part 1.

The files here are for producing MySQL as a library (e.g. a Windows DLL). The idea is that, instead of producing separate mysql (client) and mysqld (server) programs, one produces a library. Instead of sending messages, the client part merely calls the server part.

The libmysql files are split into three directories: libmysql (this one), libmysql_r (the next one), and libmysqld (the next one after that).

The "library of mysql" has some client-connection modules. For example, as described in an earlier section of this manual, there is a discussion of libmysql/libmysql.c which sends packets from the client to the server. Many of the entries in the libmysql directory (and in the following libmysqld directory) are 'symlinks' on Linux, that is, they are in fact pointers to files in other directories.

The program files on this directory are:

[edit] The libmysql_r Directory

The MySQL Library, Part 2.

There is only one file here, used to build a thread-safe libmysql library:

[edit] The libmysqld Directory

The MySQL library, Part 3.

The Embedded MySQL Server Library. The product of libmysqld is not a client/server affair, but a library. There is a wrapper to emulate the client calls. The program files on this directory are:

[edit] The man Directory

Some user-contributed manual pages

These are user-contributed "man" (manual) pages in a special markup format. The format is described in a document with a heading like "man page for man" or "macros to format man pages" which you can find in a Linux directory or on the Internet.

[edit] The myisam Directory

The MyISAM table handler.

The C files in this subdirectory come in six main groups:

The "full text" and "rtree" and "spatial" program sets are for special purposes, so this document focuses only on the mi*.c "myisam" C programs. They are:

[edit] The myisammrg Directory

MyISAM Merge table handler.

As with other table handlers, you'll find that the *.c files in the myissammrg directory have counterparts in the myisam directory. In fact, this general description of a myisammrg program is almost always true: The myisammrg function checks an argument, the myisammrg function formulates an expression for passing to a myisam function, the myisammrg calls a myisam function, the myisammrg function returns.

These are the 22 files in the myisammrg directory, with notes about the myisam functions or programs they're connected with:

[edit] The mysql-test Directory

A test suite for mysqld.

The directory has a README file which explains how to run the tests, how to make new tests (in files with the filename extension *.test), and how to report errors.

There are four subdirectories:

There are 400 *.test files in the \t subdirectory. Primarily these are SQL scripts which try out a feature, output a result, and compare the result with what's required. Some samples of what the test files check are: latin1_de comparisons, date additions, the HAVING clause, outer joins, openSSL, load data, logging, truncate, and UNION.

There are other tests in these directories:

[edit] The mysys Directory

MySQL system library. Low level routines for file access and so on.

There are 125 *.c programs in this directory:

You can find documentation for the main functions in these files elsewhere in this document. For example, the main functions in my_getwd.c are described thus: 

"int my_getwd _A((string buf, uint size, myf MyFlags));
     int my_setwd _A((const char *dir, myf MyFlags));
     Get and set working directory."

[edit] The ndb Directory

The ndb (MySQL Cluster) source code.

MySQL's shared-nothing in-memory feature is practically a DBMS by itself. We generally use the term "ndb" when referring to the storage engine, and the term "MySQL Cluster" when referring to the combination of the storage engine and the rest of the MySQL facilities.

The sub-directories within ndb are:

[edit] The netware Directory

Files related to the Novell NetWare version of MySQL.

There are 43 files on this directory. Most have filename extensions of *.def, *.sql, or *.c.

The twenty-eight *.def files are all from Novell Inc. They contain import or export symbols. (.def is a common filename extension for "definition".)

The three *.sql files are short scripts of SQL statements used in testing.

These are the five *.c files, all from Novell Inc.:

Perhaps the most important files are:

For instructions about basic installation, see "Deployment Guide For NetWare AMP" at: http://developer.novell.com/ndk/whitepapers/namp.htm

[edit] The NEW-RPMS Directory

Directory to place RPMs while making a distribution.

This directory is not part of the Windows distribution. It is a temporary directory used during RPM builds with Linux distributions. You only see it after you've done a "build".

[edit] The os2 Directory

Routines for working with the OS2 operating system.

The files in this directory are the product of the efforts of three people from outside MySQL: Yuri Dario, Timo Maier, and John M Alfredsson. There are no .C program files in this directory.

The contents of \os2 are:

The README file refers to MySQL version 3.23, which suggests that there have been no updates for MySQL 4.0 for this section.

[edit] The pstack Directory

Process stack display (not currently used).

This is a set of publicly-available debugging aids which all do pretty well the same thing: display the contents of the stack, along with symbolic information, for a running process. There are versions for various object file formats (such as ELF and IEEE-695). Most of the programs are copyrighted by the Free Software Foundation and are marked as "part of GNU Binutils".

In other words, the pstack files are not really part of the MySQL library. They are merely useful when you re-program some MYSQL code and it crashes.

[edit] The regex Directory

Henry Spencer's Regular Expression library for support of REGEXP function.

This is the copyrighted product of Henry Spencer from the University of Toronto. It's a fairly-well-known implementation of the requirements of POSIX 1003.2 Section 2.8. The library is bundled with Apache and is the default implementation for regular-expression handling in BSD Unix. MySQL's Monty Widenius has made minor changes in three programs (debug.c, engine.c, regexec.c) but this is not a MySQL package. MySQL calls it only in order to support two MySQL functions: REGEXP and RLIKE.

Some of Mr Spencer's documentation for the regex library can be found in the README and WHATSNEW files.

One MySQL program which uses regex is \cmd-line-utils\libedit\search.c

This program calls the 'regcomp' function, which is the entry point in \regex\regexp.c.

[edit] The SCCS Directory

Source Code Control System (not part of source distribution).

You will see this directory if and only if you used BitKeeper for downloading the source. The files here are for BitKeeper administration and are not of interest to application programmers.

[edit] The scripts Directory

SQL batches, e.g. mysqlbug and mysql_install_db.

The *.sh filename extension stands for "shell script". Linux programmers use it where Windows programmers would use a *.bat (batch filename extension).

Some of the *.sh files on this directory are:

[edit] The server-tools Directory

The instance manager.

Quoting from the README file within this directory: "Instance Manager - manage MySQL instances locally and remotely. File description: mysqlmanager.cc - entry point to the manager, main, options.{h,cc} - handle startup options. manager.{h,cc} - manager process. mysql_connection.{h,cc} - handle one connection with mysql client. See also instance manager architecture description in mysqlmanager.cc.

[edit] The sql Directory

Programs for handling SQL commands. The "core" of MySQL.

These are the .c and .cc files in the sql directory:

[edit] The sql-bench Directory

The MySQL Benchmarks.

This directory has the programs and input files which MySQL uses for its comparisons of MySQL, PostgreSQL, mSQL, Solid, etc. Since MySQL publishes the comparative results, it's only right that it should make available all the material necessary to reproduce all the tests.

There are five subdirectories and sub-subdirectories:

There are twenty-four *.sh (shell script) files, which involve Perl programs.

There are three *.bat (batch) files.

There is one README file and one TODO file.

[edit] The sql-common Directory

Three files: client.c, my_time.c, pack.c. You will file symlinks to these files in other directories.

[edit] The SSL Directory

Secure Sockets Layer; includes an example certification one can use test an SSL (secure) database connection.

This isn't a code directory. It contains a short note from Tonu Samuel (the NOTES file) and seven *.pem files. PEM stands for "Privacy Enhanced Mail" and is an Internet standard for adding security to electronic mail. Finally, there are two short scripts for running clients and servers over SSL connections.

[edit] The strings Directory

The string library.

Many of the files in this subdirectory are equivalent to well-known functions that appear in most C string libraries. For those, there is documentation available in most compiler handbooks.

On the other hand, some of the files are MySQL additions or improvements. Often the MySQL changes are attempts to optimize the standard libraries. It doesn't seem that anyone tried to optimize for recent Pentium class processors, though.

The .C files are:

There are also four .ASM files --- macros.asm, ptr_cmp.asm, strings.asm, and strxmov.asm --- which can replace some of the C-program functions. But again, they look like optimizations for old members of the Intel processor family.

[edit] The support-files Directory

Files used to build MySQL on different systems.

The files here are for building ("making") MySQL given a package manager, compiler, linker, and other build tools. The support files provide instructions and switches for the build processes. They include example my.cnf files one can use as a default setup for MySQL.

[edit] The tests Directory

Tests in Perl and in C.

The files in this directory are test programs that can be used as a base to write a program to simulate problems in MySQL in various scenarios: forks, locks, big records, exporting, truncating, and so on. Some examples are:

[edit] The tools Directory

Tools --- well, actually, one tool.

The only file is:

[edit] The VC++Files Directory

Visual C++ Files.

Includes this entire directory, repeated for VC++ (Windows) use.

VC++Files includes a complete environment to compile MySQL with the VC++ compiler. To use it, just copy the files on this directory; the make_win_src_distribution.sh script uses these files to create a Windows source installation.

This directory has subdirectories which are copies of the main directories. For example, there is a subdirectory \VC++Files\heap, which has the Microsoft developer studio project file to compile \heap with VC++. So for a description of the files in \VC++Files\heap, see the description of the files in \heap. The same applies for almost all of VC++Files's subdirectories (bdb, client, isam, libmysql, etc.). The difference is that the \VC++Files variants are specifically for compilation with Microsoft Visual C++ in 32-bit Windows environments.

In addition to the "subdirectories which are duplicates of directories", VC++Files contains these subdirectories, which are not duplicates:

The "nearly empty" subdirectories noted above (e.g. comp_err and isamchk) are needed because VC++ requires one directory per project (i.e. executable). We are trying to keep to the MySQL standard source layout and compile only to different directories.

[edit] The vio Directory

Virtual I/O Library.

The VIO routines are wrappers for the various network I/O calls that happen with different protocols. The idea is that in the main modules one won't have to write separate bits of code for each protocol. Thus vio's purpose is somewhat like the purpose of Microsoft's winsock library.

The underlying protocols at this moment are: TCP/IP, Named Pipes (for WindowsNT), Shared Memory, and Secure Sockets (SSL).

The C programs are:

The older functions --- raw_net_read, raw_net_write --- are now obsolete.

[edit] The zlib Directory

Data compression library, used on Windows.

zlib is a data compression library used to support the compressed protocol and the COMPRESS/UNCOMPRESS functions under Windows. On Unix, MySQL uses the system libgz.a library for this purpose.

Zlib --- which presumably stands for "Zip Library" --- is not a MySQL package. It was produced by the GNU Zip (gzip.org) people. Zlib is a variation of the famous "Lempel-Ziv" method, which is also used by "Zip". The method for reducing the size of any arbitrary string of bytes is as follows:

There is a full description of the library's functions in the gzip manual at http://www.gzip.org/zlib/manual.html. There is therefore no need to list the modules in this document.

The MySQL program \mysys\my_compress.c uses zlib for packet compression. The client sends messages to the server which are compressed by zlib. See also: \sql\net_serv.cc.

Retrieved from "http://forge.mysql.com/wiki/MySQL_Internals_Files_In_MySQL_Sources"

This page has been accessed 10,104 times. This page was last modified 16:23, 31 May 2007.

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