CHECK OPTION and a subquery in WHERE condition.
The abort was triggered by setting the value of join->tables for
subqueries in the function JOIN::cleanup. This function was called
after an invocation of the JOIN::join_free method for subqueries
used in WHERE condition.
mysql-test/r/view.result:
Added a test case for bug #28561.
mysql-test/t/view.test:
Added a test case for bug #28561.
sql/sql_select.cc:
Fixed bug #28561: assertion abort for update on multi-table view with
CHECK OPTION and a subquery in WHERE condition.
The abort was triggered by setting the value of join->tables for
subqueries in the function JOIN::cleanup. This function was called
after an invocation of the JOIN::join_free method for subqueries
used in WHERE condition.
Setting the value of join->tables to for a subquery created serious
problems for checking WHERE condition after update of the multi-table
view as this check is performed in the do_select function right
after a call of the JOIN::join_free method.
In fact setting join->tables to 0 in JOIN::cleanup is not needed
anywhere in the current code.
When processing the USE/FORCE index hints
the optimizer was not checking if the indexes
specified are enabled (see ALTER TABLE).
Fixed by:
Backporting the fix for bug 20604 to 5.0
mysql-test/r/key.result:
Test for BUG 20604.
The important part of the test is the explain output that
tests what indexes are used.
mysql-test/r/myisam.result:
Bug #28476: test cases
mysql-test/t/key.test:
Bug 20604:
The minimal test case that reveals the bug. The optimizer for
aggregates relies on keys disabled with ALTER TABLE ... DISABLE KEYS
not being in the set TABLE::keys_in_use_for_query.
When the execution engine tries to use a disabled index, MyISAM
returns an error.
mysql-test/t/myisam.test:
Bug #28476: test cases
sql/sql_base.cc:
Bug #28476:
- Ignore disabled indexes in USE/FORCE index
sql/sql_select.cc:
Bug 20604 : The intersection operation between table->s->keys_in_use
and table->keys_in_use_for_query is no longer necessary.
We can trust that the latter is a subset of the former.
sql/table.h:
Bug 20604:
Added comments to TABLE_SHARE::keys_in_use and
TABLE::keys_in_use_for_query.
mode.
When a new DATE/DATETIME field without default value is being added by the
ALTER TABLE the '0000-00-00' value is used as the default one. But it wasn't
checked whether such value was allowed by the set sql mode. Due to this
'0000-00-00' values was allowed for DATE/DATETIME fields even in the
NO_ZERO_DATE mode.
Now the mysql_alter_table() function checks whether the '0000-00-00' value
is allowed for DATE/DATETIME fields by the set sql mode.
The new error_if_not_empty flag is used in the mysql_alter_table() function
to indicate that it should abort if the table being altered isn't empty.
The new new_datetime_field field is used in the mysql_alter_table() function
for error throwing purposes.
The new error_if_not_empty parameter is added to the copy_data_between_tables()
function to indicate the it should return error if the source table isn't empty.
mysql-test/t/alter_table.test:
Added a test case for the bug#27507: Wrong DATETIME value was allowed by
ALTER TABLE in the NO_ZERO_DATE mode.
mysql-test/r/alter_table.result:
Added a test case for the bug#27507: Wrong DATETIME value was allowed by
ALTER TABLE in the NO_ZERO_DATE mode.
sql/sql_table.cc:
Bug#27507: Wrong DATETIME value was allowed by ALTER TABLE in the NO_ZERO_DATE
mode.
Now the mysql_alter_table() function checks whether the '0000-00-00' value
is allowed for DATE/DATETIME fields by the set sql mode.
The new error_if_not_empty flag is used in the mysql_alter_table() function
to indicate that it should abort if the table being altered isn't empty.
The new new_datetime_field field is used in the mysql_alter_table() function
for error throwing purposes.
The new error_if_not_empty parameter is added to the copy_data_between_tables()
function to indicate the it should return error if the source table isn't empty.
decimal_round failed to perform a correct rounding
of a decimal number if its first nine digits were '9'.
It just sets those digits to 0.
mysql-test/r/type_newdecimal.result:
Bug #27984 Long Decimal Maths produces truncated results.
test result
mysql-test/t/type_newdecimal.test:
Bug #27984 Long Decimal Maths produces truncated results.
test case
strings/decimal.c:
Bug #27984 Long Decimal Maths produces truncated results.
when to == from we break the data if we do to->buf[0]=0
So now doing this after the data is moved and only
if we really need to set to->buf[0] to zero
result max length changed for the 'decimal' fields
so test results have to be fixed
mysql-test/r/ps_2myisam.result:
Bug #28361 Buffer overflow in DECIMAL code on Windows
test result fixed
mysql-test/r/ps_3innodb.result:
Bug #28361 Buffer overflow in DECIMAL code on Windows
test result fixed
mysql-test/r/ps_4heap.result:
Bug #28361 Buffer overflow in DECIMAL code on Windows
test result fixed
mysql-test/r/ps_5merge.result:
Bug #28361 Buffer overflow in DECIMAL code on Windows
test result fixed
mysql-test/r/ps_7ndb.result:
Bug #28361 Buffer overflow in DECIMAL code on Windows
test result fixed
my_decimal in some cases can contain more decimal digits than
is officially supported (DECIMAL_MAX_PRECISION), so we need to
prepare bigger buffer for the resulting string.
mysql-test/r/type_newdecimal.result:
bug #28361 Buffer overflow in DECIMAL code on Windows
test result
mysql-test/t/type_newdecimal.test:
bug #28361 Buffer overflow in DECIMAL code on Windows
test case
This test case doesn't fall in most cases even without the fix
Still valgrind shows the problemn
sql/my_decimal.h:
bug #28361 Buffer overflow in DECIMAL code on Windows
DECIMAL_MAX_POSSIBLE_PRECISION introduced to be used in places,
when we need to check for the number of digits technicaly possible
in my_decimal.
DECIMAL_MAX_STR_LENGTH fixed as it has to fit for the MAX_POSSIBLE_PRECISION
is involved.
The Arg_comparator::compare_datetime() comparator caches its arguments if
they are constants i.e. const_item() returns true. The
Item_func_get_user_var::const_item() returns true or false based on
the current query_id and the query_id where the variable was created.
Thus even if a query can change its value its const_item() still will return
true. All this leads to a wrong comparison result when an object of the
Item_func_get_user_var class is involved.
Now the Arg_comparator::can_compare_as_dates() and the
get_datetime_value() functions never cache result of the GET_USER_VAR()
function (the Item_func_get_user_var class).
mysql-test/t/type_datetime.test:
A test case is added for the bug#28261: Wrong DATETIME comparison result when the GET_USER_VAR function
is involved.
mysql-test/r/type_datetime.result:
A test case is added for the bug#28261: Wrong DATETIME comparison result when the GET_USER_VAR function
is involved.
sql/item_cmpfunc.cc:
Bug#28261: Wrong DATETIME comparison result when the GET_USER_VAR function
is involved.
Now the Arg_comparator::can_compare_as_dates() and the
get_datetime_value() functions never cache result of the GET_USER_VAR()
function (the Item_func_get_user_var class).
Conversion errors when constructing the condition for an
IN predicates were treated as if the affected column contains
NULL. If such a IN predicate is inside NOT we get wrong
results.
Corrected the handling of conversion errors in an IN predicate
that is resolved by unique_subquery (through
subselect_uniquesubquery_engine).
mysql-test/r/subselect3.result:
Bug#22855: test case
mysql-test/t/subselect3.test:
Bug#22855: test case
sql/item_subselect.cc:
Bug#22855: corrected the handling of conversion errors and
NULL key values in IN predicate that is resolved by index
lookup.
subqueries in WHERE conditions.
This bug was introduced by the patch for bug 27321.
mysql-test/r/subselect.result:
Added a test case for bug #28337.
mysql-test/t/subselect.test:
Added a test case for bug #28337.
sql/item.cc:
Fixed bug #28337: wrong results for grouping queries with correlated
subqueries in WHERE conditions.
This bug was introduced by the patch for bug 27321.
Now in the Item_field::fix_outer_field function we create an Item_outer_ref
object for an outer reference only if it is used in the SELECT list or
in the HAVING clause of the subquery against which the reference is resolved.
- Problem was reported as a SP variable using itself as
right value inside SUBSTR caused corruption of data.
- This bug could not be verified in either 5.0bk or 5.1bk
- Added test case to prevent future regressions.
mysql-test/r/sp-vars.result:
Added test case for a reported regression which couldn't be
verified.
mysql-test/t/sp-vars.test:
Added test case for a reported regression which couldn't be
verified.
into linux-st28.site:/home/martin/mysql/src/5.0o-bug27573
mysql-test/r/func_group.result:
Auto merged
mysql-test/t/func_group.test:
bug#27573: hand merged test case
into vajra.(none):/opt/local/work/mysql-5.0-21483
sql/sp_head.cc:
Auto merged
sql/sql_base.cc:
Auto merged
sql/sql_insert.cc:
Auto merged
sql/sql_lex.h:
Auto merged
Bug#21483 "Server abort or deadlock on INSERT DELAYED with another
implicit insert"
Also fixes and adds test cases for bugs:
20497 "Trigger with INSERT DELAYED causes Error 1165"
21714 "Wrong NEW.value and server abort on INSERT DELAYED to a
table with a trigger".
Post-review fixes.
Problem:
In MySQL INSERT DELAYED is a way to pipe all inserts into a
given table through a dedicated thread. This is necessary for
simplistic storage engines like MyISAM, which do not have internal
concurrency control or threading and thus can not
achieve efficient INSERT throughput without support from SQL layer.
DELAYED INSERT works as follows:
For every distinct table, which can accept DELAYED inserts and has
pending data to insert, a dedicated thread is created to write data
to disk. All user connection threads that attempt to
delayed-insert into this table interact with the dedicated thread in
producer/consumer fashion: all records to-be inserted are pushed
into a queue of the dedicated thread, which fetches the records and
writes them.
In this design, client connection threads never open or lock
the delayed insert table.
This functionality was introduced in version 3.23 and does not take
into account existence of triggers, views, or pre-locking.
E.g. if INSERT DELAYED is called from a stored function, which,
in turn, is called from another stored function that uses the delayed
table, a deadlock can occur, because delayed locking by-passes
pre-locking. Besides:
* the delayed thread works directly with the subject table through
the storage engine API and does not invoke triggers
* even if it was patched to invoke triggers, if triggers,
in turn, used other tables, the delayed thread would
have to open and lock involved tables (use pre-locking).
* even if it was patched to use pre-locking, without deadlock
detection the delayed thread could easily lock out user
connection threads in case when the same table is used both
in a trigger and on the right side of the insert query:
the delayed thread would not release locks until all inserts
are complete, and user connection can not complete inserts
without having locks on the tables used on the right side of the
query.
Solution:
These considerations suggest two general alternatives for the
future of INSERT DELAYED:
* it is considered a full-fledged alternative to normal INSERT
* it is regarded as an optimisation that is only relevant
for simplistic engines.
Since we missed our chance to provide complete support of new
features when 5.0 was in development, the first alternative
currently renders infeasible.
However, even the second alternative, which is to detect
new features and convert DELAYED insert into a normal insert,
is not easy to implement.
The catch-22 is that we don't know if the subject table has triggers
or is a view before we open it, and we only open it in the
delayed thread. We don't know if the query involves pre-locking
until we have opened all tables, and we always first create
the delayed thread, and only then open the remaining tables.
This patch detects the problematic scenarios and converts
DELAYED INSERT to a normal INSERT using the following approach:
* if the statement is executed under pre-locking (e.g. from
within a stored function or trigger) or the right
side may require pre-locking, we detect the situation
before creating a delayed insert thread and convert the statement
to a conventional INSERT.
* if the subject table is a view or has triggers, we shutdown
the delayed thread and convert the statement to a conventional
INSERT.
mysql-test/r/insert.result:
Update test results.
mysql-test/t/insert.test:
Add a test case for Bug#21483, Bug#20497, Bug#21714 (INSERT DELAYED
and stored routines, triggers).
sql/sp_head.cc:
Upgrade lock type to TL_WRITE when computing the pre-locking set.
sql/sql_base.cc:
Use a new method.
sql/sql_insert.cc:
INSERT DELAYED and pre-locking:
- if under pre-locking, upgrade the lock type to TL_WRITE
and proceed as a normal write
- if DELAYED table has triggers, also request a lock upgrade.
- make sure errors in the delayed thread are propagated
correctly
sql/sql_lex.h:
Add a method to check if a parsed tree refers to stored
routines.
in the case of the overflow in the decimal->integer conversion
we didn't return the proper boundary value, but just the result
of the conversion we calculated on the moment of the error
mysql-test/r/bigint.result:
bug #8663 cant use bigint unsigned as input to cast
test result fixed
mysql-test/t/bigint.test:
bug #8663 cant use bigint unsigned as input to cast
test case
strings/decimal.c:
bug #8663 cant use bigint unsigned as input to cast
decimal->int conversion fixed to return proper boundary value
in the case of overflow
function.
A wrong condition was used to check that the
Arg_comparator::can_compare_as_dates() function calculated the value of the
string constant. When comparing a non-const STRING function with a constant
DATETIME function it leads to saving an arbitrary value as a cached value of
the DATETIME function.
Now the Arg_comparator::set_cmp_func() function initializes the const_value
variable to the impossible DATETIME value (-1) and this const_value is
cached only if it was changed by the Arg_comparator::can_compare_as_dates()
function.
mysql-test/t/type_datetime.test:
Added a test case for the bug#28208: Wrong result of a non-const STRING function with a const DATETIME function.
mysql-test/r/type_datetime.result:
Added a test case for the bug#28208: Wrong result of a non-const STRING function with a const DATETIME function.
sql/item_cmpfunc.cc:
Bug#28208: Wrong result of a non-const STRING function with a const DATETIME
function.
Now the Arg_comparator::set_cmp_func() function initializes the const_value
variable to the impossible DATETIME value (-1) and this const_value is
cached only if it was changed by the Arg_comparator::can_compare_as_dates()
function.
into olga.mysql.com:/home/igor/dev-opt/mysql-5.0-opt-bug28272
mysql-test/r/innodb_mysql.result:
Auto merged
mysql-test/t/innodb_mysql.test:
Auto merged
sql/sql_select.cc:
Manual merge
to NULL
For queries of the form SELECT MIN(key_part_k) FROM t1
WHERE key_part_1 = const and ... and key_part_k-1 = const,
the opt_sum_query optimization tries to
use an index to substitute MIN/MAX functions with their values according
to the following rules:
1) Insert the minimum non-null values where the WHERE clause still matches, or
3) A row of nulls
However, the correct semantics requires that there is a third case 2)
such that a NULL value is substituted if there are only NULL values for
key_part_k.
The patch modifies opt_sum_query() to handle this missing case.
mysql-test/r/func_group.result:
Bug #27573: Correct result
mysql-test/t/func_group.test:
Bug #27573: test case
sql/opt_sum.cc:
Bug #27573:
Added code that will try to read the
first non-null value for a given complete-field prefix, second
choice is to read the null, and lastly set the error code if no row
is found.
into vajra.(none):/opt/local/work/mysql-5.0-runtime
sql/item.cc:
Auto merged
sql/item_func.cc:
Auto merged
sql/mysql_priv.h:
Auto merged
sql/set_var.cc:
Auto merged
sql/sql_class.h:
Auto merged
sql/sql_insert.cc:
Auto merged
sql/sql_parse.cc:
Auto merged
sql/sql_prepare.cc:
Auto merged
sql/sql_yacc.yy:
Auto merged
for a query over an empty table right after its creation.
The crash is the result of an attempt made by JOIN::optimize to evaluate
the WHERE condition when no records have been actually read.
The added test case can reproduce the crash only with InnoDB tables and
only with 5.0.x.
mysql-test/r/innodb_mysql.result:
Added a test case for bug #28272.
mysql-test/t/innodb_mysql.test:
Added a test case for bug #28272.
sql/sql_select.cc:
Fixed bug #28272: crash that occurs when running an EXPLAIN command
for a query over an empty table right after its creation.
The crash is the result of an attempt made by JOIN::optimize to evaluate
the WHERE condition when no records have been actually read.
Such attempts could be observed only with EXPLAIN commands.
Now at the optimization phase the WHERE condition is never evaluated if
there is no record previously read from the table.
statement from a UNION query with ORDER BY an expression containing
RAND().
The crash happened because the global order by list in the union query
was not re-initialized for execution.
(Local order by lists were re-initialized though).
mysql-test/r/ps.result:
Added a test case for bug #27937.
mysql-test/t/ps.test:
Added a test case for bug #27937.
sql/sql_union.cc:
Fixed bug #27937: crash for the the second execution of a prepared
statement from a UNION query with ORDER BY an expression containing
RAND().
The crash happened because the global order by list in the union query
was not re-initialized for execution.
(Local order by lists were re-initialized though).
Added re-initialization of the global order by list in the function
st_select_lex_unit::init_prepare_fake_select_lex.
a crash when the left operand of the predicate is evaluated to NULL.
It happens when the rows from the inner tables (tables from the subquery)
are accessed by index methods with key values obtained by evaluation of
the left operand of the subquery predicate. When this predicate is
evaluated to NULL an alternative access with full table scan is used
to check whether the result set returned by the subquery is empty or not.
The crash was due to the fact the info about the access methods used for
regular key values was not properly restored after a switch back from the
full scan access method had occurred.
The patch restores this info properly.
The same problem existed for queries with IN subquery predicates if they
were used not at the top level of the queries.
mysql-test/r/subselect3.result:
Added a test case for bug #28375.
mysql-test/t/subselect3.test:
Added a test case for bug #28375.
sql/item_subselect.cc:
Fixed bug #28375: a query with an NOT IN subquery predicate may cause
a crash when the left operand of the predicate is evaluated to NULL.
It happens when the rows from the inner tables (tables from the subquery)
are accessed by index methods with key values obtained by evaluation of
the left operand of the subquery predicate. When this predicate is
evaluated to NULL an alternative access with full table scan is used
to check whether the result set returned by the subquery is empty or not.
The crash was due to the fact the info about the access methods used for
regular key values was not properly restored after a switch back from the
full scan access method had occurred.
The patch restores this info properly.
sql/sql_select.h:
Fixed bug #28375: a query with an NOT IN subquery predicate may cause
a crash when the left operand of the predicate is evaluated to NULL.
In the JOIN_TAB structure two fields have been added to save info about
index methods used to access the subquery rows. The saved info is used
after a switch back from the alternative full scan access method has
occurred. The full scan is used when the left operand of the subquery
predicate is evaluated to NULL.
Corrected test case for the bug#27878.
mysql-test/t/grant.test:
Corrected test case for the bug#27878.
mysql-test/r/grant.result:
Corrected test case for the bug#27878.
database.
If a user has a right to update anything in the current database then the
access was granted and further checks of access rights for underlying tables
wasn't done correctly. The check is done before a view is opened and thus no
check of access rights for underlying tables can be carried out.
This allows a user to update through a view a table from another database for
which he hasn't enough rights.
Now the mysql_update() and the mysql_test_update() functions are forces
re-checking of access rights after a view is opened.
mysql-test/t/grant.test:
Added a test case for the bug#27878: Unchecked privileges on a view referring to a table from another database.
mysql-test/r/grant.result:
Added a test case for the bug#27878: Unchecked privileges on a view referring to a table from another database.
sql/sql_update.cc:
Bug#27878: Unchecked privileges on a view referring to a table from another
database.
Now the mysql_update() function forces re-checking of access rights after
the view is opened.
sql/sql_prepare.cc:
Bug#27878: Unchecked privileges on a view referring to a table from another
database.
Now the mysql_test_update() function forces re-checking of access rights after
the view is opened.
into mockturtle.local:/home/dlenev/src/mysql-5.0-cts-3
sql/mysql_priv.h:
Auto merged
sql/sql_insert.cc:
Auto merged
sql/sql_prepare.cc:
Auto merged
sql/sql_yacc.yy:
Auto merged
Bug #20662 "Infinite loop in CREATE TABLE IF NOT EXISTS ... SELECT
with locked tables"
Bug #20903 "Crash when using CREATE TABLE .. SELECT and triggers"
Bug #24738 "CREATE TABLE ... SELECT is not isolated properly"
Bug #24508 "Inconsistent results of CREATE TABLE ... SELECT when
temporary table exists"
Deadlock occured when one tried to execute CREATE TABLE IF NOT
EXISTS ... SELECT statement under LOCK TABLES which held
read lock on target table.
Attempt to execute the same statement for already existing
target table with triggers caused server crashes.
Also concurrent execution of CREATE TABLE ... SELECT statement
and other statements involving target table suffered from
various races (some of which might've led to deadlocks).
Finally, attempt to execute CREATE TABLE ... SELECT in case
when a temporary table with same name was already present
led to the insertion of data into this temporary table and
creation of empty non-temporary table.
All above problems stemmed from the old implementation of CREATE
TABLE ... SELECT in which we created, opened and locked target
table without any special protection in a separate step and not
with the rest of tables used by this statement.
This underminded deadlock-avoidance approach used in server
and created window for races. It also excluded target table
from prelocking causing problems with trigger execution.
The patch solves these problems by implementing new approach to
handling of CREATE TABLE ... SELECT for base tables.
We try to open and lock table to be created at the same time as
the rest of tables used by this statement. If such table does not
exist at this moment we create and place in the table cache special
placeholder for it which prevents its creation or any other usage
by other threads.
We still use old approach for creation of temporary tables.
Also note that we decided to postpone introduction of some tests
for concurrent behaviour of CREATE TABLE ... SELECT till 5.1.
The main reason for this is absence in 5.0 ability to set @@debug
variable at runtime, which can be circumvented only by using several
test files with individual .opt files. Since the latter is likely
to slowdown test-suite unnecessary we chose not to push this tests
into 5.0, but run them manually for this version and later push
their optimized version into 5.1
mysql-test/r/create.result:
Extended test coverage for CREATE TABLE ... SELECT. In particular added
tests for bug #24508 "Inconsistent results of CREATE TABLE ... SELECT
when temporary table exists" and bug #20662 "Infinite loop in CREATE
TABLE IF NOT EXISTS ... SELECT with locked tables".
mysql-test/r/trigger.result:
Added test case for bug #20903 "Crash when using CREATE TABLE .. SELECT
and triggers"
mysql-test/t/create.test:
Extended test coverage for CREATE TABLE ... SELECT. In particular added
tests for bug #24508 "Inconsistent results of CREATE TABLE ... SELECT
when temporary table exists" and bug #20662 "Infinite loop in CREATE
TABLE IF NOT EXISTS ... SELECT with locked tables".
mysql-test/t/trigger.test:
Added test case for bug #20903 "Crash when using CREATE TABLE .. SELECT
and triggers"
sql/lock.cc:
Now for creation of name-lock placeholder in lock_table_name() we use
auxiliary function table_cache_insert_placeholder().
sql/mysql_priv.h:
Made build_table_path() function available outside of sql_table.cc file.
reopen_name_locked_table() now has 3rd argument which controls linking
in of table being opened into THD::open_tables (this is useful in
cases when placeholder used for name-locking is already linked into
this list).
Added declaration of auxiliary function table_cache_insert_placeholder()
which is used for creation of table placeholders for name-locking.
Added declaration of table_cache_has_open_placeholder() function which
can be used for checking if table cache contains an open placeholder for
the table and if this placeholder was created by another thread.
(This function is needed only in 5.0 where we use it in various versions
of CREATE TABLE in order to protect it from concurrent CREATE TABLE
... SELECT operations for the table. Starting from 5.1 we use different
approach so it is going to be removed there).
Made close_old_data_files() static within sql_base.cc file.
Added auxiliary drop_open_table() routine.
Moved declaration of refresh_version to table.h header to make it
accessible from inline methods of TABLE class.
MYSQL_OPEN_IGNORE_LOCKED_TABLES flag is no longer used. Instead
MYSQL_OPEN_TEMPORARY_ONLY option was added.
sql/sql_base.cc:
Added support for the new approach to the handling of CREATE TABLE
... SELECT for base tables.
Now we try to open and lock table to be created at the same time as
the rest of tables used by this statement. If such table does not
exist at this moment we create and place in the table cache special
placeholder for it which prevents its creation or any other usage
by other threads.
Note significant distinctions of this placeholder from the placeholder
used for normal name-lock: 1) It is treated like open table by other
name-locks so it does not allow name-lock taking operations like DROP
TABLE or RENAME TABLE to proceed. 2) it is linked into THD::open_tables
list and automatically removed during close_thread_tables() call.
open_tables():
Implemented logic described above. To do this added
auxiliary check_if_table_exists() function.
Removed support for MYSQL_OPEN_IGNORE_LOCKED_TABLES option
which is no longer used.
Added MYSQL_OPEN_TEMPORARY_ONLY which is used to restrict
search for temporary tables only.
close_cached_tables()/close_thread_table()/reopen_tables()/
close_old_data_files()/table_is_used()/remove_table_from_cache():
Added support for open placeholders (note that we also use them
when we need to re-open tables during flush).
Added auxiliary drop_open_table() routine.
reopen_name_locked_table():
Now has 3rd argument which controls linking in of table being
opened into THD::open_tables (this is useful in cases when
placeholder used for name-locking is already linked into
this list).
Added auxiliary table_cache_insert_placeholder() routine which
simplifies creation of placeholders used for name-locking.
Added table_cache_has_open_placeholder() function which can be
used for checking if table cache contains an open placeholder for
the table and if this placeholder was created by another thread.
(This function is needed only in 5.0 where we use it in various versions
of CREATE TABLE in order to protect it from concurrent CREATE TABLE
... SELECT operations for the table. Starting from 5.1 we use different
approach so it is going to be removed there).
sql/sql_handler.cc:
Adjusted mysql_ha_mark_tables_for_reopen() routine to properly
handle placeholders which now can be linked into open tables
list.
sql/sql_insert.cc:
Introduced new approach to handling of base tables in CREATE TABLE
... SELECT statement.
Now we try to open and lock table to be created at the same time as
the rest of tables used by this statement. If such table does not
exist at this moment we create and place in the table cache special
placeholder for it which prevents its creation or any other usage
by other threads. By doing this we avoid races which existed with
previous approach in which we created, opened and locked target in
separate step without any special protection.
This also allows properly calculate prelocking set in cases when
target table already exists and has some on insert triggers.
Note that we don't employ the same approach for temporary tables
(this is okay as such tables are unaffected by other threads).
Changed create_table_from_items() and select_create methods to
implement this approach.
sql/sql_parse.cc:
The new approach to handling of CREATE TABLE ... SELECT for
base tables assumes that all tables (including table to be
created) are opened and (or) locked at the same time.
So in cases when we create base table we have to pass to
open_and_lock_tables() table list which includes target table.
sql/sql_prepare.cc:
The new approach to handling of CREATE TABLE ... SELECT for
base tables assumes that all tables (including table to be
created) are opened and (or) locked at the same time.
So in cases when we create base table we have to pass to
open_and_lock_tables() table list which includes target table.
sql/sql_table.cc:
Now mysql_create_table_internal(), mysql_create_like_table() and
mysql_alter_table() not only check that destination table doesn't
exist on disk but also check that there is no create placeholder
in table cache for it (i.e. there is no CREATE TABLE ... SELECT
operation in progress for it). Note that starting from 5.1 we
use different approach in order to to protect CREATE TABLE ... SELECT
from concurrent CREATE TABLE (ALTER TABLE ... RENAME) operations,
the latter simply take name-locks on table before its creation
(on target table name before renaming).
Also made build_table_path() available from other files and
asjusted calls to reopen_name_locked_table(), which now takes
extra argument, which controls linking of open table into
THD::open_tables list.
sql/sql_trigger.cc:
reopen_name_locked_tables() now has one more argument which controls
linking of opened table into the THD::open_tables list.
sql/sql_yacc.yy:
The new approach to handling of CREATE TABLE ... SELECT statement
for base tables assumes that all tables including table to be
created are open and (or) locked at the same time. Therefore
we need to set correct lock for target table.
sql/table.h:
Moved declaration of refresh_version variable from mysql_priv.h
to make it accessible from inline methods of TABLE class.
Renamed TABLE::locked_by_flush member to open_placeholder since
now it is also used for taking exclusive name-lock and not only
by flush.
Introduced TABLE::is_name_opened() helper method which can be used
to distinguish TABLE instances corresponding to open tables or
placeholders for them from closed instances (e.g. due to their old
version). Also introduced TABLE::needs_reopen_or_name_lock() helper
which allows to check if TABLE instance corresponds to outdated
version of table or to name-lock placeholder.
Introduced TABLE_LIST::create member which marks elements of
table list corresponds to the table to be created.
Adjusted TABLE_LIST::placeholder() method to take into account
name-lock placeholders for tables to be created (this, for example,
allows to properly handle such placeholders in lock_tables()).
