"Federated Denial of Service"
Federated storage engine used to attempt to open connections within
the ::create() and ::open() methods which are invoked while LOCK_open
mutex is being held by mysqld. As a result, no other client sessions
can open tables while Federated is attempting to open a connection.
Long DNS lookup times would stall mysqld's operation and a rogue
connection string which connects to a remote server which simply
stalls during handshake can stall mysqld for a much longer period of
time.
This patch moves the opening of the connection much later, when the
federated actually issues queries, by which time the LOCK_open mutex is
no longer being held.
when creating table
Federated tables had an artificially low maximum of key length,
because the handler failed to implement a method to return it and
the default value is taked from the prototype handler.
Now, implement that method and return the maximum possible key
length, which is that of InnoDB.
"Federated INSERT failures"
Federated does not correctly handle "INSERT...ON DUPLICATE KEY UPDATE"
However, implementing such support is not reasonably possible without
increasing complexity of the storage engine: checking that constraints
on remote server match local server and parsing error messages.
This patch causes 'ON DUPLICATE KEY' to fail with ER_DUP_KEY message
if a conflict occurs and not to fail silently.
"REPLACE/INSERT IGNORE/UPDATE IGNORE doesn't work"
Federated does not record neccessary HA_EXTRA flags in order to
support REPLACE/INSERT IGNORE/UPDATE IGNORE.
Implement ::extra() to capture flags neccessary for functionality.
New function append_ident() to better escape identifiers consistantly.
- Added 'SET NAMES <charset>" upon ::open
- Added test and results for simple UTF test
federated.test:
BUG #17044 Federated Storage Engine not UTF8 clean
New test. Using hex - pasting various charsets in the terminal doesn't work.
federated.result:
BUG# 17044 Federated Storage Engine not UTF8 clean
New test results
ha_federated.cc:
BUG# 17044 Federated Storage Engine not UTF8 clean
Upon ::open, set names to table's charset
Added HA_NULL_IN_KEY to table flags to allow for nullable unique indexes
and added test to verify
ha_federated.h:
BUG #15133 "unique index with nullable value not accepted in federated table"
added HA_NULL_IN_KEY to table flags to allow for nullable unique indexes
federated.test:
BUG #15133 "unique index with nullable value not accepted in federated table"
New test to show that nullable unique indexes work
federated.result:
BUG #15133 "unique index with nullable value not accepted in federated table"
New results for new test
When a default of '' was specified for TEXT/BLOB columns, the specification
was silently ignored. This is presumably to be nice to applications (or
people) who generate their column definitions in a not-very-clever fashion.
For clarity, doing this now results in a warning, or an error in strict
mode.
The Federated storage engine used Field methods that had arbitrary limits on
the amount of data they could process, which caused problems with data
over that limit (4K). By removing those Field methods and just using
features of the String class, we can avoid this problem.
NDB table".
SQL-layer was not marking fields which were used in triggers as such. As
result these fields were not always properly retrieved/stored by handler
layer. So one might got wrong values or lost changes in triggers for NDB,
Federated and possibly InnoDB tables.
This fix solves the problem by marking fields used in triggers
appropriately.
Also this patch contains the following cleanup of ha_ndbcluster code:
We no longer rely on reading LEX::sql_command value in handler in order
to determine if we can enable optimization which allows us to handle REPLACE
statement in more efficient way by doing replaces directly in write_row()
method without reporting error to SQL-layer.
Instead we rely on SQL-layer informing us whether this optimization
applicable by calling handler::extra() method with
HA_EXTRA_WRITE_CAN_REPLACE flag.
As result we no longer apply this optimzation in cases when it should not
be used (e.g. if we have on delete triggers on table) and use in some
additional cases when it is applicable (e.g. for LOAD DATA REPLACE).
Finally this patch includes fix for bug#20728 "REPLACE does not work
correctly for NDB table with PK and unique index".
This was yet another problem which was caused by improper field mark-up.
During row replacement fields which weren't explicity used in REPLACE
statement were not marked as fields to be saved (updated) so they have
retained values from old row version. The fix is to mark all table
fields as set for REPLACE statement. Note that in 5.1 we already solve
this problem by notifying handler that it should save values from all
fields only in case when real replacement happens.
When building the UPDATE query to send to the remote server, the
federated storage engine built the query incorrectly if it was updating
a field to be NULL.
Thanks to Bjrn Steinbrink for an initial patch for the problem.
new file
mysql_fix_privilege_tables.sql, mysql_create_system_tables.sh:
Adding true BINARY/VARBINARY: fixing "password" type, not to be 0x00-padding.
Many files:
Adding true BINARY/VARBINARY: fixing tests not to output 0x00 bytes.
Adding true BINARY/VARBINARY: new pad_char structure member.
ctype-bin.c:
Adding true BINARY/VARBINARY: new pad_char structure member.
New strnxfrm, with two trailing length bytes.
field.cc:
Adding true BINARY/VARBINARY.
