Added a test case for bug #6447.
mf_keycache.c:
Fixed bug #6447. Erronious code in the key_cache_read function
caused problems when reading key blocks with offset>0 into
key cache. The code of key_cache_insert and key_cache_write
was modified similarly.
Introduced a new free blocks list. Free blocks are now re-used before
new blocks are allocated from the pool. There is a new status variable
which can be queried by "show status like key_blocks_unused".
New multi-key-cache handling. This was needed becasue the old one didn't work reliable with MERGE tables.
ALTER TABLE table_name ... CHARACTER SET ... now changes all char/varchar/text columns to the given character set
(One must use ALTER TABLE ... DEFAULT CHARACTER SET ... to change the default character set)
Fixed that have_compress is detected properly (fixes problems with func_compress.test on platforms without zlib)
New syntax for CACHE INDEX ('keys' is optional if no index name is given and one mentions the key cache name only ones)
Removed compiler warnings
Added mysql_set_server_option() to allow clients like PHP to easaily set/reset the multi-statement flag.
