一个表最多可以包含 1017 列。虚拟生成列也包含在此限制内。A table can contain a maximum of 1017 columns. Virtual generated columns are included in this limit.

一个表最多可以包含 64 个 二级索引。A table can contain a maximum of 64 secondary indexes.

对于使用 DYNAMIC 或 COMPRESSED 行格式的 InnoDB 表，索引键前缀长度的限制为 3072 字节。The index key prefix length limit is 3072 bytes for InnoDB tables that use DYNAMIC or COMPRESSED row format.

对于使用 REDUNDANT 或 COMPACT 行格式的 InnoDB 表，索引键前缀长度的限制为 767 字节。例如，如果在 TEXT 或 VARCHAR 列上使用超过 191 个字符的 列前缀 索引，并且使用 utf8mb4 字符集且每个字符最多占 4 个字节，就可能会遇到此限制。The index key prefix length limit is 767 bytes for InnoDB tables that use the REDUNDANT or COMPACT row format. For example, you might hit this limit with a column prefix index of more than 191 characters on a TEXT or VARCHAR column, assuming a utf8mb4 character set and the maximum of 4 bytes for each character.

尝试使用超过限制的索引键前缀长度会返回错误。Attempting to use an index key prefix length that exceeds the limit returns an error.

如果在创建 MySQL 实例时通过指定 innodb_page_size 选项将 InnoDB 页面大小 减小到 8KB 或 4KB，则索引键的最大长度将按比例降低，基于 16KB 页面大小的 3072 字节限制。也就是说，当页面大小为 8KB 时，最大索引键长度为 1536 字节；页面大小为 4KB 时为 768 字节。If you reduce the InnoDB page size to 8KB or 4KB by specifying the innodb_page_size option when creating the MySQL instance, the maximum length of the index key is lowered proportionally, based on the limit of 3072 bytes for a 16KB page size. That is, the maximum index key length is 1536 bytes when the page size is 8KB, and 768 bytes when the page size is 4KB.

适用于索引键前缀的限制也适用于完整列索引键。The limits that apply to index key prefixes also apply to full-column index keys.

多列索引最多允许 16 列。超过此限制会返回错误。A maximum of 16 columns is permitted for multicolumn indexes. Exceeding the limit returns an error.

ERROR 1070 (42000): Too many key parts specified; max 16 parts allowed

最大行大小（不包括存储在页外的任何可变长度列）对于 4KB、8KB、16KB 和 32KB 的页大小略小于一页的一半。例如，默认 innodb_page_size 为 16KB 时，最大行大小约为 8000 字节。然而，对于 64KB 的 InnoDB 页大小，最大行大小约为 16000 字节。LONGBLOB 和 LONGTEXT 列必须小于 4GB，并且包括 BLOB 和 TEXT 列的总行大小必须小于 4GB。The maximum row size, excluding any variable-length columns that are stored off-page, is slightly less than half of a page for 4KB, 8KB, 16KB, and 32KB page sizes. For example, the maximum row size for the default innodb_page_size of 16KB is about 8000 bytes. However, for an InnoDB page size of 64KB, the maximum row size is approximately 16000 bytes. LONGBLOB and LONGTEXT columns must be less than 4GB, and the total row size, including BLOB and TEXT columns, must be less than 4GB.

如果一行小于半页长，则整行数据都会在页面内本地存储。如果超过半页长，则会选择可变长度的列进行页外存储，直到行在半页内放下，如第 17.11.2 节，“文件空间管理”中所述。If a row is less than half a page long, all of it is stored locally within the page. If it exceeds half a page, variable-length columns are chosen for external off-page storage until the row fits within half a page, as described in Section 17.11.2, “File Space Management”.

尽管InnoDB内部支持行大小超过 65,535 字节，但 MySQL 本身对所有列的总行大小限制为 65,535 字节。请参阅第 10.4.7 节，“表列数和行大小限制”。Although InnoDB supports row sizes larger than 65,535 bytes internally, MySQL itself imposes a row-size limit of 65,535 for the combined size of all columns. See Section 10.4.7, “Limits on Table Column Count and Row Size”.

最大表或表空间的大小受到服务器文件系统的影响，文件系统可能会施加一个最大文件大小，该大小可能比 InnoDB 定义的内部 64 TiB 大小限制还小。例如，Linux 上的 ext4 文件系统的最大文件大小为 16 TiB，因此最大表或表空间的大小变为 16 TiB，而不是 64 TiB。另一个例子是 FAT32 文件系统，其最大文件大小为 4 GB。The maximum table or tablespace size is impacted by the server's file system, which can impose a maximum file size that is smaller than the internal 64 TiB size limit defined by InnoDB. For example, the ext4 file system on Linux has a maximum file size of 16 TiB, so the maximum table or tablespace size becomes 16 TiB instead of 64 TiB. Another example is the FAT32 file system, which has a maximum file size of 4 GB.

如果需要更大的系统表空间，请使用多个较小的数据文件来配置，而不是使用一个大型数据文件，或者将表数据分布在每表一个文件和通用表空间数据文件中。If you require a larger system tablespace, configure it using several smaller data files rather than one large data file, or distribute table data across file-per-table and general tablespace data files.

InnoDB 日志文件的总最大大小为 512GB。The combined maximum size for InnoDB log files is 512GB.

最小表空间大小略大于 10MB。最大表空间大小取决于InnoDB页大小。The minimum tablespace size is slightly larger than 10MB. The maximum tablespace size depends on the InnoDB page size.

最大表空间大小也是表的最大大小。The maximum tablespace size is also the maximum size for a table.

一个InnoDB实例最多支持 2^32（4294967296）个表空间，其中少量表空间用于撤销和临时表。An InnoDB instance supports up to 2^32 (4294967296) tablespaces, with a small number of those tablespaces reserved for undo and temporary tables.

共享表空间支持最多 2^32 (4294967296) 张表。Shared tablespaces support up to 2^32 (4294967296) tables.

表空间文件的路径，包括文件名，不能超过 Windows 上的 MAX_PATH 限制。在 Windows 10 之前，MAX_PATH 限制为 260 个字符。从 Windows 10 版本 1607 起，常用的 Win32 文件和目录函数中已取消 MAX_PATH 限制，但您必须启用此新行为。The path of a tablespace file, including the file name, cannot exceed the MAX_PATH limit on Windows. Prior to Windows 10, the MAX_PATH limit is 260 characters. As of Windows 10, version 1607, MAX_PATH limitations are removed from common Win32 file and directory functions, but you must enable the new behavior.

有关并发读写事务相关的限制，请参见 第 17.6.6 节，“撤销日志”。For limits associated with concurrent read-write transactions, see Section 17.6.6, “Undo Logs”.