Maximum Indexes Per Table

Maximum Indexes per Table

The number of indexes that can be accommodated for each table is limited.The actual maximum for a specific table depends on the page size and the number of columns in the indexes.

Table 1. Maximum Indexes per Table
Page Size	Number of Indexes Depending on Column Count
Page Size	Single	2-Column	3-Column
4096	203	145	113
8192	408	291	227
16384	818	584	454
32768	1637	1169	909

Character Index Limits

The maximum indexed string length is 9 bytes less than the maximum key length.The maximum indexable string length depends on the page size, the character set, and the collation.

Table 1. Maximum indexable (VAR)CHAR length
Page Size	Maximum Indexable String Length by Charset Type
Page Size	1 byte/char	2 byte/char	3 byte/char	4 byte/char
4096	1015	507	338	253
8192	2039	1019	679	509
16384	4087	2043	1362	1021
32768	8183	4091	2727	2045

Note	Depending on the collation, the maximum size can be further reduced as case-insensitive and accent-insensitive collations require more bytes per character in an index.See also Character Indexes in Chapter Data Types and Subtypes.