build)
The crash was caused by freeing the internal parser stack during the parser
execution.
This occured only for complex stored procedures, after reallocating the parser
stack using my_yyoverflow(), with the following C call stack:
- MYSQLparse()
- any rule calling sp_head::restore_lex()
- lex_end()
- x_free(lex->yacc_yyss), xfree(lex->yacc_yyvs)
The root cause is the implementation of stored procedures, which breaks the
assumption from 4.1 that there is only one LEX structure per parser call.
The solution is to separate the LEX structure into:
- attributes that represent a statement (the current LEX structure),
- attributes that relate to the syntax parser itself (Yacc_state),
so that parsing multiple statements in stored programs can create multiple
LEX structures while not changing the unique Yacc_state.
Now, Yacc_state and the existing Lex_input_stream are aggregated into
Parser_state, a structure that represent the complete state of the (Lexical +
Syntax) parser.
slave
The stored-routine code took the contents of the (lowest) parser
and copied it directly to the binlog, which causes problems if there
is a special case of interpretation at the parser level -- which
there is, in the "/*!VER */" comments. The trailing "*/" caused
errors on the slave, naturally.
Now, since by that point we have /properly/ created parse-tree (as
the rest of the server should do!) for the stored-routine CREATE, we
can construct a perfect statement from that information, instead of
writing uncertain information from an unknown parser state.
Fortunately, there's already a function nearby that does exactly
that.
---
Update for Bug#36570. Qualify routine names with db name when
writing to the binlog ONLY if the source text is qualified.
Add metadata validation to ~20 more SQL commands. Make sure that
these commands actually work in ps-protocol, since until now they
were enabled, but not carefully tested.
Fixes the ml003 bug found by Matthias during internal testing of the
patch.
between 5.0 and 5.1.
The problem was that in the patch for Bug#11986 it was decided
to store original query in UTF8 encoding for the INFORMATION_SCHEMA.
This approach however turned out to be quite difficult to implement
properly. The main problem is to preserve the same IS-output after
dump/restore.
So, the fix is to rollback to the previous functionality, but also
to fix it to support multi-character-set-queries properly. The idea
is to generate INFORMATION_SCHEMA-query from the item-tree after
parsing view declaration. The IS-query should:
- be completely in UTF8;
- not contain character set introducers.
For more information, see WL4052.
a SELECT doesn't cause ROLLBACK of statem".
The idea of the fix is to ensure that we always commit the current
statement at the end of dispatch_command(). In order to not issue
redundant disc syncs, an optimization of the two-phase commit
protocol is implemented to bypass the two phase commit if
the transaction is read-only.
pre-locking.
The crash was caused by an implicit assumption in check_table_access() that
table_list parameter is always a part of lex->query_tables.
When iterating over the passed list of tables, check_table_access() used
to stop only when lex->query_tables_last_not_own was reached.
In case of pre-locking, lex->query_tables_last_own is not NULL and points
to some element of lex->query_tables. When the parameter
of check_table_access() was not part of lex->query_tables, loop invariant
could never be violated and a crash would happen when the current table
pointer would point beyond the end of the provided list.
The fix is to change the signature of check_table_access() to also accept
a numeric limit of loop iterations, similarly to check_grant(), and
supply this limit in all places when we want to check access of tables
that are outside lex->query_tables, or just want to check access to one table.
Bug 33983 (Stored Procedures: wrong end <label> syntax is accepted)
The server used to crash when REPEAT or another control instruction
was used in conjunction with labels and a LEAVE instruction.
The crash was caused by a missing "pop" of handlers or cursors in the
code representing the stored program. When executing the code in a loop,
this missing "pop" would result in a stack overflow, corrupting memory.
Code generation has been fixed to produce the missing h_pop/c_pop
instructions.
Also, the logic checking that labels at the beginning and the end of a
statement are matched was incorrect, causing Bug 33983.
End labels, when used, must match the label used at the beginning of a block.
cause ROLLBACK of statement", part 1. Review fixes.
Do not send OK/EOF packets to the client until we reached the end of
the current statement.
This is a consolidation, to keep the functionality that is shared by all
SQL statements in one place in the server.
Currently this functionality includes:
- close_thread_tables()
- log_slow_statement().
After this patch and the subsequent patch for Bug#12713, it shall also include:
- ha_autocommit_or_rollback()
- net_end_statement()
- query_cache_end_of_result().
In future it may also include:
- mysql_reset_thd_for_next_command().
When the server was out of memory it crashed because of invalid memory access.
This patch adds detection for failed memory allocations and make the server
output a proper error message.
If a stored function that contains a drop temporary table statement
is invoked by a create temporary table of the same name may cause
a server crash. The problem is that when dropping a table no check
is done to ensure that table is not being used by some outer query
(or outer statement), potentially leaving the outer query with a
reference to a stale (freed) table.
The solution is when dropping a temporary table, always check if
the table is being used by some outer statement as a temporary
table can be dropped inside stored procedures.
The check is performed by looking at the TABLE::query_id value for
temporary tables. To simplify this check and to solve a bug related
to handling of temporary tables in prelocked mode, this patch changes
the way in which this member is used to track the fact that table is
used/unused. Now we ensure that TABLE::query_id is zero for unused
temporary tables (which means that all temporary tables which were
used by a statement should be marked as free for reuse after it's
execution has been completed).
The value of the actual argument of BIT-type-arg stored procedure was binlogged as non-escaped
sequence of bytes corresponding to internal representation of the bit value.
The patch enforces binlogging of the bit-argument as a valid literal: prefixing the quoted bytes
sequence with _binary.
Note, that behaviour of Item_field::var_str for field_type() of MYSQL_TYPE_BIT is exceptional
in that the returned string contains the binary representation even though result_type() of
the item is INT_RESULT.
The general log write function (general_log_print) uses printf style
arguments which need to be pre-processed, meaning that the all arguments
are copied to a single buffer and the problem is that the buffer size is
constant (1022 characters) but queries can be much larger then this.
The solution is to introduce a new log write function that accepts a
buffer and it's length as arguments. The function is to be used when
a formatted output is not required, which is the case for almost all
query write-to-log calls.
This is a incompatible change with respect to the log format of prepared
statements.
Bug#29816 Syntactically wrong query fails with misleading error message
The core problem is that an SQL-invoked function name can be a <schema
qualified routine name> that contains no <schema name>, but the mysql
parser insists that all stored procedures (function, procedures and
triggers) must have a <schema name>, which is not true for functions.
This problem is especially visible when trying to create a function
or when a query contains a syntax error after a function call (in the
same query), both will fail with a "No database selected" message if
the session is not attached to a particular schema, but the first
one should succeed and the second fail with a "syntax error" message.
Part of the fix is to revamp the sp name handling so that a schema
name may be omitted for functions -- this means that the internal
function name representation may not have a dot, which represents
that the function doesn't have a schema name. The other part is
to place schema checks after the type (function, trigger or procedure)
of the routine is known.
of statement breaks binlog.
There were two problems discovered by this bug:
1. Default (current) database is not fixed at the creation time.
That leads to wrong output of DATABASE() function.
2. Database attributes (@@collation_database) are not fixed at
the creation time. That leads to wrong resultset.
Binlog breakage and Query Cache wrong output happened because of
the first problem.
The fix is to remember the current database at the PREPARE-time and
set it each time at EXECUTE.
