diff options
Diffstat (limited to 'innobase/include/dict0mem.h')
| -rw-r--r-- | innobase/include/dict0mem.h | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/innobase/include/dict0mem.h b/innobase/include/dict0mem.h index 3c10e82342b..7d8dc404290 100644 --- a/innobase/include/dict0mem.h +++ b/innobase/include/dict0mem.h @@ -159,10 +159,13 @@ struct dict_col_struct{ in some of the functions below */ }; -/* DICT_MAX_INDEX_COL_LEN is measured in bytes and is the max index column -length + 1. Starting from 4.1.6, we set it to < 3 * 256, so that one can -create a column prefix index on 255 characters of a TEXT field also in the -UTF-8 charset. In that charset, a character may take at most 3 bytes. */ +/* DICT_MAX_INDEX_COL_LEN is measured in bytes and is the maximum +indexed column length (or indexed prefix length). It is set to 3*256, +so that one can create a column prefix index on 256 characters of a +TEXT or VARCHAR column also in the UTF-8 charset. In that charset, +a character may take at most 3 bytes. +This constant MUST NOT BE CHANGED, or the compatibility of InnoDB data +files would be at risk! */ #define DICT_MAX_INDEX_COL_LEN 768 |