Implement worklog #5743 InnoDB: Lift the limit of index key prefixes.

With this change, the index prefix column length lifted from 767 bytes
to 3072 bytes if "innodb_large_prefix" is set to "true".

rb://603 approved by Marko

1 files changed, 14 insertions, 6 deletions

diff --git a/storage/innobase/include/rem0types.h b/storage/innobase/include/rem0types.h
index 8b84d4af233..7afd595be90 100644
--- a/storage/innobase/include/rem0types.h
+++ b/storage/innobase/include/rem0types.h
@@ -34,13 +34,21 @@ typedef byte	rec_t;
 #define REC_MAX_HEAP_NO		(2 * 8192 - 1)
 #define REC_MAX_N_OWNED		(16 - 1)
 
-/* REC_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.
+/* REC_ANTELOPE_MAX_INDEX_COL_LEN is measured in bytes and is the maximum
+indexed field length (or indexed prefix length) for indexes on tables of
+ROW_FORMAT=REDUNDANT and ROW_FORMAT=COMPACT format.
+Before we support UTF-8 encodings with mbmaxlen = 4, a UTF-8 character
+may take at most 3 bytes.  So the limit was 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.
 This constant MUST NOT BE CHANGED, or the compatibility of InnoDB data
 files would be at risk! */
-#define REC_MAX_INDEX_COL_LEN	768
+#define REC_ANTELOPE_MAX_INDEX_COL_LEN		768
+
+/** Maximum indexed field length for table format DICT_TF_FORMAT_ZIP and
+beyond.
+This (3072) is the maximum index row length allowed, so we cannot create index
+prefix column longer than that. */
+#define REC_VERSION_56_MAX_INDEX_COL_LEN	3072
 
 #endif