causes full table lock on innodb table.
Also fixes Bug#28502 Triggers that update another innodb table
will block on X lock unnecessarily (duplciate).
Code review fixes.
Both bugs' synopses are misleading: InnoDB table is
not X locked. The statements, however, cannot proceed concurrently,
but this happens due to lock conflicts for tables used in triggers,
not for the InnoDB table.
If a user had an InnoDB table, and two triggers, AFTER UPDATE and
AFTER INSERT, competing for different resources (e.g. two distinct
MyISAM tables), then these two triggers would not be able to execute
concurrently. Moreover, INSERTS/UPDATES of the InnoDB table would
not be able to run concurrently.
The problem had other side-effects (see respective bug reports).
This behavior was a consequence of a shortcoming of the pre-locking
algorithm, which would not distinguish between different DML operations
(e.g. INSERT and DELETE) and pre-lock all the tables
that are used by any trigger defined on the subject table.
The idea of the fix is to extend the pre-locking algorithm to keep track,
for each table, what DML operation it is used for and not
load triggers that are known to never be fired.
fails if a database is not selected prior.
The problem manifested itself when a user tried to
create a routine that had non-fully-qualified identifiers in its bodies
and there was no current database selected.
This is a regression introduced by the fix for Bug 19022:
The patch for Bug 19022 changes the code to always produce a warning
if we can't resolve the current database in the parser.
In this case this was not necessary, since even though the produced
parsed tree was incorrect, we never re-use sphead
that was obtained at first parsing of CREATE PROCEDURE.
The sphead that is anyhow used is always obtained through db_load_routine,
and there we change the current database to sphead->m_db before
calling yyparse.
The idea of the fix is to resolve the current database directly using
lex->sphead->m_db member when parsing a stored routine body, when
such is present.
This patch removes the need to reset the current database
when loading a trigger or routine definition into SP cache.
The redundant code will be removed in 5.1.
profiling. Also,
Bug#26938: profiling client hang if used before enabled
In the SHOW command, not sending header data because we had no
rows to send was a protocol violation. Porting the SHOW PROFILE
command to use the Information Schema table avoids that problem.
- BUG#11986: Stored routines and triggers can fail if the code
has a non-ascii symbol
- BUG#16291: mysqldump corrupts string-constants with non-ascii-chars
- BUG#19443: INFORMATION_SCHEMA does not support charsets properly
- BUG#21249: Character set of SP-var can be ignored
- BUG#25212: Character set of string constant is ignored (stored routines)
- BUG#25221: Character set of string constant is ignored (triggers)
There were a few general problems that caused these bugs:
1. Character set information of the original (definition) query for views,
triggers, stored routines and events was lost.
2. mysqldump output query in client character set, which can be
inappropriate to encode definition-query.
3. INFORMATION_SCHEMA used strings with mixed encodings to display object
definition;
1. No query-definition-character set.
In order to compile query into execution code, some extra data (such as
environment variables or the database character set) is used. The problem
here was that this context was not preserved. So, on the next load it can
differ from the original one, thus the result will be different.
The context contains the following data:
- client character set;
- connection collation (character set and collation);
- collation of the owner database;
The fix is to store this context and use it each time we parse (compile)
and execute the object (stored routine, trigger, ...).
2. Wrong mysqldump-output.
The original query can contain several encodings (by means of character set
introducers). The problem here was that we tried to convert original query
to the mysqldump-client character set.
Moreover, we stored queries in different character sets for different
objects (views, for one, used UTF8, triggers used original character set).
The solution is
- to store definition queries in the original character set;
- to change SHOW CREATE statement to output definition query in the
binary character set (i.e. without any conversion);
- introduce SHOW CREATE TRIGGER statement;
- to dump special statements to switch the context to the original one
before dumping and restore it afterwards.
Note, in order to preserve the database collation at the creation time,
additional ALTER DATABASE might be used (to temporary switch the database
collation back to the original value). In this case, ALTER DATABASE
privilege will be required. This is a backward-incompatible change.
3. INFORMATION_SCHEMA showed non-UTF8 strings
The fix is to generate UTF8-query during the parsing, store it in the object
and show it in the INFORMATION_SCHEMA.
Basically, the idea is to create a copy of the original query convert it to
UTF8. Character set introducers are removed and all text literals are
converted to UTF8.
This UTF8 query is intended to provide user-readable output. It must not be
used to recreate the object. Specialized SHOW CREATE statements should be
used for this.
The reason for this limitation is the following: the original query can
contain symbols from several character sets (by means of character set
introducers).
Example:
- original query:
CREATE VIEW v1 AS SELECT _cp1251 'Hello' AS c1;
- UTF8 query (for INFORMATION_SCHEMA):
CREATE VIEW v1 AS SELECT 'Hello' AS c1;
Problem: separator was not converted to the result character set,
so the result was a mixture of two different character sets,
which was especially bad for UCS2.
Fix: convert separator to the result character set.
ALTER VIEW is currently not supported as a prepared statement
and should be disabled as such as they otherwise could cause server crashes.
ALTER VIEW is currently not supported when called from stored
procedures or functions for related reasons and should also be disabled.
This patch disables these DDL statements and adjusts the appropriate test
cases accordingly.
Additional tests has been added to reflect on the fact that we do support
CREATE/ALTER/DROP TABLE for Prepared Statements (PS), Stored Procedures (SP)
and PS within SP.
Changed code to enforce that SQL_CACHE only in the first SELECT is used to turn on caching(as documented), but any SQL_NO_CACHE will turn off caching (not documented, but a useful behaviour, especially for machine generated queries). Added test cases to explicitly test the documented caching behaviour and test cases for the reported bug.
Bug 28127 (Some valid identifiers names are not parsed correctly)
Bug 26302 (MySQL server cuts off trailing "*/" from comments in SP/func)
This patch is the second part of a major cleanup, required to fix
Bug 25411 (trigger code truncated).
The root cause of the issue stems from the function skip_rear_comments,
which was a work around to remove "extra" "*/" characters from the query
text, when parsing a query and reusing the text fragments to represent a
view, trigger, function or stored procedure.
The reason for this work around is that "special comments",
like /*!50002 XXX */, were not parsed properly, so that a query like:
AAA /*!50002 BBB */ CCC
would be seen by the parser as "AAA BBB */ CCC" when the current version
is greater or equal to 5.0.2
The root cause of this stems from how special comments are parsed.
Special comments are really out-of-bound text that appear inside a query,
that affects how the parser behave.
In nature, /*!50002 XXX */ in MySQL is similar to the C concept
of preprocessing :
#if VERSION >= 50002
XXX
#endif
Depending on the current VERSION of the server, either the special comment
should be expanded or it should be ignored, but in all cases the "text" of
the query should be re-written to strip the "/*!50002" and "*/" markers,
which does not belong to the SQL language itself.
Prior to this fix, these markers would leak into :
- the storage format for VIEW,
- the storage format for FUNCTION,
- the storage format for FUNCTION parameters, in mysql.proc (param_list),
- the storage format for PROCEDURE,
- the storage format for PROCEDURE parameters, in mysql.proc (param_list),
- the storage format for TRIGGER,
- the binary log used for replication.
In all cases, not only this cause format corruption, but also provide a vector
for dormant security issues, by allowing to tunnel code that will be activated
after an upgrade.
The proper solution is to deal with special comments strictly during parsing,
when accepting a query from the outside world.
Once a query is parsed and an object is created with a persistant
representation, this object should not arbitrarily mutate after an upgrade.
In short, special comments are a useful but limited feature for MYSQLdump,
when used at an *interface* level to facilitate import/export,
but bloating the server *internal* storage format is *not* the proper way
to deal with configuration management of the user logic.
With this fix:
- the Lex_input_stream class now acts as a comment pre-processor,
and either expands or ignore special comments on the fly.
- MYSQLlex and sql_yacc.yy have been cleaned up to strictly use the
public interface of Lex_input_stream. In particular, how the input stream
accepts or rejects a character is private to Lex_input_stream, and the
internal buffer pointers of that class are strictly private, and should not
be tempered with during parsing.
This caused many changes mostly in sql_lex.cc.
During the code cleanup in case MY_LEX_NUMBER_IDENT,
Bug 28127 (Some valid identifiers names are not parsed correctly)
was found and fixed.
By parsing special comments properly, and removing the function
'skip_rear_comments' [sic],
Bug 26302 (MySQL server cuts off trailing "*/" from comments in SP/func)
has been fixed as well.
Coding style: classes start with a capital letter.
Rename some classes related to parsing:
create_field -> Create_field
foreign_key -> Foreign_key
key_part_spec -> Key_part_spec
