'conc_sys' test
Concurrent execution of SELECT involing at least two INFORMATION_SCHEMA
tables, DROP DATABASE statement and DROP TABLE statement could have
resulted in stalled connection for this SELECT statement.
The problem was that for the first query of a join there was a race
between select from I_S.TABLES and DROP DATABASE, and the error (no
such database) was prepared to be send to the client, but the join
processing was continued. On second query to I_S.COLUMNS there was a
race with DROP TABLE, but this error (no such table) was downgraded to
warning, and thd->net.report_error was reset. And so neither result
nor error was sent to the client.
The solution is to stop join processing once it is clear we are going
to report a error, and also to downgrade to warnings file system errors
like 'no such database' (unless we are in the 'SHOW' command), because
I_S is designed not to use locks and the query to I_S should not abort
if something is dropped in the middle.
No test case is provided since this bug is a result of a race, and is
timing dependant. But we test that plain SHOW TABLES and SHOW COLUMNS
give a error if there is no such database or a table respectively.
Fix for BUG#16676: Database CHARSET not used for stored procedures
The problem in BUG#16211 is that CHARSET-clause of the return type for
stored functions is just ignored.
The problem in BUG#16676 is that if character set is not explicitly
specified for sp-variable, the server character set is used instead
of the database one.
The fix has two parts:
- always store CHARSET-clause of the return type along with the
type definition in mysql.proc.returns column. "Always" means that
CHARSET-clause is appended even if it has not been explicitly
specified in CREATE FUNCTION statement (this affects BUG#16211 only).
Storing CHARSET-clause if it is not specified is essential to avoid
changing character set if the database character set is altered in
the future.
NOTE: this change is not backward compatible with the previous releases.
- use database default character set if CHARSET-clause is not explicitly
specified (this affects both BUG#16211 and BUG#16676).
NOTE: this also breaks backward compatibility.
a non-correlated single-row subquery over information schema.
The function get_all_tables filling all information schema
tables reset lex->sql_command to SQLCOM_SHOW_FIELDS. After
this the function could evaluate partial conditions related to
some columns. If these conditions contained a subquery over
information schema it led to a wrong evaluation and a wrong
result set.
This bug was already fixed in 5.1.
This patch follows the way how it was done in 5.1 where
the value of lex->sql_command is set to SQLCOM_SHOW_FIELDS
in get_all_tables only for the calls of the function
open_normal_and_derived_tables and is restored after these
calls.
subqueries on information schema that use MIN/MAX aggregation.
Execution of some correlated subqueries may set the value
of null_row to 1 for tables used in the subquery.
If the the subquery is on information schema it causes
rejection of any row for the following executions of
the subquery in the case when an optimization filtering
by some condition is applied.
The fix restores the value of the null_row flag for
each execution of a subquery on information schema.
Table comment: issue a warning(error in traditional mode) if length of comment > 60 symbols
Column comment: issue a warning(error in traditional mode) if length of comment > 255 symbols
Table 'comment' is changed from char* to LEX_STRING
After view onening real view db name and table name are placed
into table_list->view_db & table_list->view_name.
Item_field class does not handle these names properly during
intialization of Send_field.
The fix is to use new class 'Item_ident_for_show'
which sets correct view db name and table name for Send_field.
fix: return db name for I_S.TABLES(and others) in original letter case.
if mysql starts with lower_case_table_names=1 | 2 then original db name is converted
to lower case(for I_S tables). It happens when we perform add_table_to_list.
to avoid this we make a copy of original db name and use the copy hereafter.
Bug#18282 "INFORMATION_SCHEMA.TABLES provides inconsistent info about invalid views"
This bug caused crashes or resulted in wrong data being returned
when one tried to obtain information from I_S tables about views
using stored functions.
It was caused by the fact that we were using LEX representing
statement which were doing select from I_S tables as active LEX
when contents of I_S table were built. So state of this LEX both
affected and was affected by open_tables() calls which happened
during this process. This resulted in wrong behavior and in
violations of some of invariants which caused crashes.
This fix tries to solve this problem by properly saving/resetting
and restoring part of LEX which affects and is affected by the
process of opening tables and views in get_all_tables() routine.
To simplify things we separated this part of LEX in a new class
and made LEX its descendant.
mysqldump / SHOW CREATE TABLE will show the NEXT available value for
the PK, rather than the *first* one that was available (that named in
the original CREATE TABLE ... AUTO_INCREMENT = ... statement).
This should produce correct and robust behaviour for the obvious use
cases -- when no data were inserted, then we'll produce a statement
featuring the same value the original CREATE TABLE had; if we dump
with values, INSERTing the values on the target machine should set the
correct next_ID anyway (and if not, we'll still have our AUTO_INCREMENT =
... to do that). Lastly, just the CREATE statement (with no data) for
a table that saw inserts would still result in a table that new values
could safely be inserted to).
There seems to be no robust way however to see whether the next_ID
field is > 1 because it was set to something else with CREATE TABLE
... AUTO_INCREMENT = ..., or because there is an AUTO_INCREMENT column
in the table (but no initial value was set with AUTO_INCREMENT = ...)
and then one or more rows were INSERTed, counting up next_ID. This
means that in both cases, we'll generate an AUTO_INCREMENT =
... clause in SHOW CREATE TABLE / mysqldump. As we also show info on,
say, charsets even if the user did not explicitly give that info in
their own CREATE TABLE, this shouldn't be an issue.
As per above, the next_ID will be affected by any INSERTs that have
taken place, though. This /should/ result in correct and robust
behaviour, but it may look non-intuitive to some users if they CREATE
TABLE ... AUTO_INCREMENT = 1000 and later (after some INSERTs) have
SHOW CREATE TABLE give them a different value (say, CREATE TABLE
... AUTO_INCREMENT = 1006), so the docs should possibly feature a
caveat to that effect.
It's not very intuitive the way it works now (with the fix), but it's
*correct*. We're not storing the original value anyway, if we wanted
that, we'd have to change on-disk representation?
If we do dump/load cycles with empty DBs, nothing will change. This
changeset includes an additional test case that proves that tables
with rows will create the same next_ID for AUTO_INCREMENT = ... across
dump/restore cycles.
Confirmed by support as likely solution for client's problem.
Crash happened when one selected data from one of INFORMATION_SCHEMA
tables and in order to build its contents server had to open view which
used stored function and table or view on which one had not global or
database-level privileges (e.g. had only table-level or had no
privileges at all).
The crash was caused by usage of check_grant() function, which assumes
that either number of tables to be inspected by it is limited explicitly
or table list used and thd->lex->query_tables_own_last value correspond
to each other (the latter should be either 0 or point to next_global
member of one of elements of this table list), in conditions when
above assumptions were not true. This fix just explicitly limits
number of tables to be inspected. Other negative effects which are
caused by the fact that thd->lex->query_tables_own_last might not
be set properly during processing of I_S tables are less disastrous
and will be reported and fixed separetely.
There are two main idea of this fix:
- introduce a common function for server and client to split user value
(<user name>@<host name>) into user name and host name parts;
- dump DEFINER clause in correct format in mysqldump.
Bug#14387 SHOW COLUMNS doesn't work on temporary tables.
Bug#15224 SHOW INDEX from temporary table doesn't work.
Restore thd->temporary_tables to be able to process
temporary tables(only for 'show index' & 'show columns').
This should be changed when processing of temporary tables for
I_S tables will be done.
Bad examples of usage of a string with its length fixed.
The incorrect length in the trigger file configuration descriptor
fixed (BUG#14090).
A hook for unknown keys added to the parser to support old .TRG files.
