mysql 大小限制_MySql表大小限制 | 学步园

1.4.4. How Big MySQL Tables Can Be

MySQL 3.22 had a 4GB (4 gigabyte) limit on table size. With the MyISAM storage engine in MySQL 3.23, the maximum table size was increased to 65536 terabytes (2567 – 1 bytes). With this larger allowed table size, the maximum effective table size for MySQL databases is usually determined by operating system constraints on file sizes, not by MySQL internal limits.

The InnoDB storage engine maintains InnoDB tables within a tablespace that can be created from several files. This allows a table to exceed the maximum individual file size. The tablespace can include raw disk partitions, which allows extremely large tables. The maximum tablespace size is 64TB.

The following table lists some examples of operating system file-size limits. This is only a rough guide and is not intended to be definitive. For the most up-to-date information, be sure to check the documentation specific to your operating system.

Operating System File-size Limit

Linux 2.2-Intel 32-bit 2GB (LFS: 4GB)

Linux 2.4+ (using ext3 filesystem) 4TB

Solaris 9/10 16TB

NetWare w/NSS filesystem 8TB

win32 w/ FAT/FAT32 2GB/4GB

win32 w/ NTFS 2TB (possibly larger)

MacOS X w/ HFS+ 2TB

On Linux 2.2, you can get MyISAM tables larger than 2GB in size by using the Large File Support (LFS) patch for the ext2 filesystem. On Linux 2.4, patches also exist for ReiserFS to get support for big files (up to 2TB). Most current Linux distributions are based on kernel 2.4 and include all the required LFS patches. With JFS and XFS, petabyte and larger files are possible on Linux. However, the maximum available file size still depends on several factors, one of them being the filesystem used to store MySQL tables.

For a detailed overview about LFS in Linux, have a look at Andreas Jaeger's Large File Support in Linux page at http://www.suse.de/~aj/linux_lfs.html.

Windows users please note: FAT and VFAT (FAT32) are not considered suitable for production use with MySQL. Use NTFS instead.

By default, MySQL creates MyISAM tables with an internal structure that allows a maximum size of about 4GB. You can check the maximum table size for a table with the SHOW TABLE STATUS statement or with myisamchk -dv tbl_name. See Section 13.5.4, “SHOW Syntax”.

If you need a MyISAM table that is larger than 4GB in size (and your operating system supports large files), the CREATE TABLE statement allows AVG_ROW_LENGTH and MAX_ROWS options. See Section 13.1.5, “CREATE TABLE Syntax”. You can also change these options with ALTER TABLE after the table has been created, to increase the table's maximum allowable size. See Section 13.1.2, “ALTER TABLE Syntax”.

Other ways to work around file-size limits for MyISAM tables are as follows:

If your large table is read-only, you can use myisampack to compress it. myisampack usually compresses a table by at least 50%, so you can have, in effect, much bigger tables. myisampack also can merge multiple tables into a single table. See Section 8.2, “myisampack — Generate Compressed, Read-Only MyISAM Tables”.

MySQL includes a MERGE library that allows you to handle a collection of MyISAM tables that have identical structure as a single MERGE table. See Section 14.3, “The MERGE Storage Engine”.