Too many cursors (more than 1024) could lead to memory corruption.
This affects both, stored routines and C API cursors, and the
threshold is per-server, not per-connection. Similarly, the
corruption could happen when the server was under heavy load
(executing more than 1024 simultaneous complex queries), and this is
the reason why this bug is fixed in 4.1, which doesn't support
cursors.
The corruption was caused by a bug in the temporary tables code, when
an attempt to create a table could lead to a write beyond allocated
space. Note, that only internal tables were affected (the tables
created internally by the server to resolve the query), not tables
created with CREATE TEMPORARY TABLE. Another pre-condition for the
bug is TRUE value of --temp-pool startup option, which, however, is a
default.
The cause of a bug was that random memory was overwritten in
bitmap_set_next() due to out-of-bound memory access.
This patch allows to configure MyISAM for 128 indexes per table.
The main problem is the key_map, wich is implemented as an ulonglong.
To get rid of the limit and keep the efficient and flexible
implementation, the highest bit is now used for all upper keys.
This means that the lower keys can be disabled and enabled
individually as usual and the high keys can only be disabled and
enabled as a block. That way the existing test suite is still
applicable, while more keys work, though slightly less efficient.
To really get more than 64 keys, some defines need to be changed.
Another patch will address this.
Changed defaults option --instance to --defaults-group-suffix
Changed option handling to allow --defaults-file, --defaults-extra-file and --defaults-group-suffix to be given in any order
Changed MYSQL_INSTANCE to MYSQL_GROUP_SUFFIX
mysql_print_defaults now understands --defaults-group-suffix
Remove usage of my_tempnam() (not safe function)
if( -> if ( and while( to while (
* Fixed a problem with wrong query results for partially covering keys in ROR-index_merge
* ROR-intersection retrieval plan choice algorithm now uses less disk IO
- and properly processes clustered PK range scans
* Fixed several minor range optimizer problems
* Added more comments
* Code cleanup
New records_in_range() interface (similar to read_range())
Macros for faster bitmap handling
Simplify read_range() code (#WL1786)
New general key_cmp() function to compare keys
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.
added extra/mysql_install.c - will work on it in 4.0, but it does not hurt
to have it sit in 3.23 tree for now since it will eventually be backported
to 3.23 anyway
Allow delete of crashed MyISAM tables
Fixed bug when BLOB was first part of key
Fixed bug when using result from CASE in GROUP BY
Fixed core-dump bug in monthname()
Optimized calling of check_db_name()
