savepoint support was added a year ago as get_last_memroot_block()
and free_all_new_blocks(), but it didn't work and was disabled.
* fix it to work
* instead of freeing the memory, only mark blocks free - this feature
is supposed to be used inside a loop (otherwise there is no need
to free anything, end of statement will do it anyway). And freeing
blocks inside a loop is a bad idea, as they'll be all malloc-ed
on the next iteration again. So, don't.
* fix a bug in mark_blocks_free() - it doesn't change the number of blocks
During a query execution some sorting and grouping operations
on strings may be involved. System variable max_sort_length defines
the maximum number of bytes to use when comparing strings during
sorting/grouping. Thus, the comparable parts of strings may be less
than their actual size, so the results of the query may be not
sorted/grouped properly.
To indicate that some comparisons were done on a truncated lengths,
a new warning has been introduced with this commit.
Step#1: fixing the return type of strnxfrm() from size_t to this structure:
typedef struct
{
size_t m_output_length;
size_t m_source_length_used;
uint m_warnings;
} my_strnxfrm_ret_t;
Don't allow the referencing key column from NULL TO NOT NULL
when
1) Foreign key constraint type is ON UPDATE SET NULL
2) Foreign key constraint type is ON DELETE SET NULL
3) Foreign key constraint type is UPDATE CASCADE and referenced
column declared as NULL
Don't allow the referenced key column from NOT NULL to NULL
when foreign key constraint type is UPDATE CASCADE
and referencing key columns doesn't allow NULL values
get_foreign_key_info(): InnoDB sends the information about
nullability of the foreign key fields and referenced key fields.
fk_check_column_changes(): Enforce the above rules for COPY
algorithm
innobase_check_foreign_drop_col(): Checks whether the dropped
column exists in existing foreign key relation
innobase_check_foreign_low() : Enforce the above rules for
INPLACE algorithm
dict_foreign_t::check_fk_constraint_valid(): This is used
by CREATE TABLE statement to check nullability for foreign
key relation.
When using the default innodb_log_buffer_size=2m, mariadb-backup --backup
would spend a lot of time re-reading and re-parsing the log. For reads,
it would be beneficial to memory-map the entire ib_logfile0 to the
address space (typically 48 bits or 256 TiB) and read it from there,
both during --backup and --prepare.
We will introduce the Boolean read-only parameter innodb_log_file_mmap
that will be OFF by default on most platforms, to avoid aggressive
read-ahead of the entire ib_logfile0 in when only a tiny portion would be
accessed. On Linux and FreeBSD the default is innodb_log_file_mmap=ON,
because those platforms define a specific mmap(2) option for enabling
such read-ahead and therefore it can be assumed that the default would
be on-demand paging. This parameter will only have impact on the initial
InnoDB startup and recovery. Any writes to the log will use regular I/O,
except when the ib_logfile0 is stored in a specially configured file system
that is backed by persistent memory (Linux "mount -o dax").
We also experimented with allowing writes of the ib_logfile0 via a
memory mapping and decided against it. A fundamental problem would be
unnecessary read-before-write in case of a major page fault, that is,
when a new, not yet cached, virtual memory page in the circular
ib_logfile0 is being written to. There appears to be no way to tell
the operating system that we do not care about the previous contents of
the page, or that the page fault handler should just zero it out.
Many references to HAVE_PMEM have been replaced with references to
HAVE_INNODB_MMAP.
The predicate log_sys.is_pmem() has been replaced with
log_sys.is_mmap() && !log_sys.is_opened().
Memory-mapped regular files differ from MAP_SYNC (PMEM) mappings in the
way that an open file handle to ib_logfile0 will be retained. In both
code paths, log_sys.is_mmap() will hold. Holding a file handle open will
allow log_t::clear_mmap() to disable the interface with fewer operations.
It should be noted that ever since
commit 685d958e38 (MDEV-14425)
most 64-bit Linux platforms on our CI platforms
(s390x a.k.a. IBM System Z being a notable exception) read and write
/dev/shm/*/ib_logfile0 via a memory mapping, pretending that it is
persistent memory (mount -o dax). So, the memory mapping based log
parsing that this change is enabling by default on Linux and FreeBSD
has already been extensively tested on Linux.
::log_mmap(): If a log cannot be opened as PMEM and the desired access
is read-only, try to open a read-only memory mapping.
xtrabackup_copy_mmap_snippet(), xtrabackup_copy_mmap_logfile():
Copy the InnoDB log in mariadb-backup --backup from a memory
mapped file.
Applied SR transaction on the child table was not BF aborted by TOI running
on the parent table for several reasons:
Although SR correctly collected FK-referenced keys to parent, TOI in Galera
disregards common certification index and simply sets itself to depend on
the latest certified write set seqno.
Since this write set was the fragment of SR transaction, TOI was allowed to
run in parallel with SR presuming it would BF abort the latter.
At the same time, DML transactions in the server don't grab MDL locks on
FK-referenced tables, thus parent table wasn't protected by an MDL lock from
SR and it couldn't provoke MDL lock conflict for TOI to BF abort SR transaction.
In InnoDB, DDL transactions grab shared MDL locks on child tables, which is not
enough to trigger MDL conflict in Galera.
InnoDB-level Wsrep patch didn't contain correct conflict resolution logic due to
the fact that it was believed MDL locking should always produce conflicts correctly.
The fix brings conflict resolution rules similar to MDL-level checks to InnoDB,
thus accounting for the problematic case.
Apart from that, wsrep_thd_is_SR() is patched to return true only for executing
SR transactions. It should be safe as any other SR state is either the same as
for any single write set (thus making the two logically equivalent), or it reflects
an SR transaction as being aborting or prepared, which is handled separately in
BF-aborting logic, and for regular execution path it should not matter at all.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
- Lex_ident_cli* into a new file sql/lex_ident_cli.h
- Lex_ident_sys* into a new file sql/lex_ident_sys.h
- Well_formed_prefix into include/m_ctype.h
This change is needed to the optimizer hint parser coming soon.
Apart from better performance when accessing thread local variables,
we'll get rid of things that depend on initialization/cleanup of
pthread_key_t variables.
Where appropriate, use compiler-dependent pre-C++11 thread-local
equivalents, where it makes sense, to avoid initialization check overhead
that non-static thread_local can suffer from.
The strncpy() wrapper that was introduced in
commit 567b681299
is checking whether the output was truncated even in cases
where the caller does not care about it.
Let us introduce a separate function safe_strcpy_truncated() that
indidates whether the output was truncated.
The shared counter template ib_counter_t uses the function
my_timer_cycles() as a source of pseudo-random numbers to pick a shard.
On some platforms, my_timer_cycles() could return the constant value 0.
get_rnd_value(): Remove.
my_pseudo_random(): Implement as an alias of my_timer_cycles() or
a wrapper for pthread_self().
Reviewed by: Vladislav Vaintroub
Changes:
- Fixed that MyISAM and Aria parallel repair works with tmp file limit.
This required to add current_thd to all parallel workers and add
protection in my_malloc_size_cb_func() and temp_file_size_cb_func() to
be able to handle shared THD's. I removed the old code in MyISAM to
set current_thd() as only worked when using with virtal indexed
columns and I wanted to keep the Aria and MyISAM code identical.
Other things:
- Improved error messages from Aria parallel repair and
create_internal_tmp_table_from_heap().
Two new variables added:
- max_tmp_space_usage : Limits the the temporary space allowance per user
- max_total_tmp_space_usage: Limits the temporary space allowance for
all users.
New status variables: tmp_space_used & max_tmp_space_used
New field in information_schema.process_list: TMP_SPACE_USED
The temporary space is counted for:
- All SQL level temporary files. This includes files for filesort,
transaction temporary space, analyze, binlog_stmt_cache etc.
It does not include engine internal temporary files used for repair,
alter table, index pre sorting etc.
- All internal on disk temporary tables created as part of resolving a
SELECT, multi-source update etc.
Special cases:
- When doing a commit, the last flush of the binlog_stmt_cache
will not cause an error even if the temporary space limit is exceeded.
This is to avoid giving errors on commit. This means that a user
can temporary go over the limit with up to binlog_stmt_cache_size.
Noteworthy issue:
- One has to be careful when using small values for max_tmp_space_limit
together with binary logging and with non transactional tables.
If a the binary log entry for the query is bigger than
binlog_stmt_cache_size and one hits the limit of max_tmp_space_limit
when flushing the entry to disk, the query will abort and the
binary log will not contain the last changes to the table.
This will also stop the slave!
This is also true for all Aria tables as Aria cannot do rollback
(except in case of crashes)!
One way to avoid it is to use @@binlog_format=statement for
queries that updates a lot of rows.
Implementation:
- All writes to temporary files or internal temporary tables, that
increases the file size, are routed through temp_file_size_cb_func()
which updates and checks the temp space usage.
- Most of the temporary file monitoring is done inside IO_CACHE.
Temporary file monitoring is done inside the Aria engine.
- MY_TRACK and MY_TRACK_WITH_LIMIT are new flags for ini_io_cache().
MY_TRACK means that we track the file usage. TRACK_WITH_LIMIT means
that we track the file usage and we give an error if the limit is
breached. This is used to not give an error on commit when
binlog_stmp_cache is flushed.
- global_tmp_space_used contains the total tmp space used so far.
This is needed quickly check against max_total_tmp_space_usage.
- Temporary space errors are using EE_LOCAL_TMP_SPACE_FULL and
handler errors are using HA_ERR_LOCAL_TMP_SPACE_FULL.
This is needed until we move general errors to it's own error space
so that they cannot conflict with system error numbers.
- Return value of my_chsize() and mysql_file_chsize() has changed
so that -1 is returned in the case my_chsize() could not decrease
the file size (very unlikely and will not happen on modern systems).
All calls to _chsize() are updated to check for > 0 as the error
condition.
- At the destruction of THD we check that THD::tmp_file_space == 0
- At server end we check that global_tmp_space_used == 0
- As a precaution against errors in the tmp_space_used code, one can set
max_tmp_space_usage and max_total_tmp_space_usage to 0 to disable
the tmp space quota errors.
- truncate_io_cache() function added.
- Aria tables using static or dynamic row length are registered in 8K
increments to avoid some calls to update_tmp_file_size().
Other things:
- Ensure that all handler errors are registered. Before, some engine
errors could be printed as "Unknown error".
- Fixed bug in filesort() that causes a assert if there was an error
when writing to the temporay file.
- Fixed that compute_window_func() now takes into account write errors.
- In case of parallel replication, rpl_group_info::cleanup_context()
could call trans_rollback() with thd->error set, which would cause
an assert. Fixed by resetting the error before calling trans_rollback().
- Fixed bug in subselect3.inc which caused following test to use
heap tables with low value for max_heap_table_size
- Fixed bug in sql_expression_cache where it did not overflow
heap table to Aria table.
- Added Max_tmp_disk_space_used to slow query log.
- Fixed some bugs in log_slow_innodb.test
- FLUSH GLOBAL STATUS now resets most global_status_vars.
At this stage, this is mainly to be used for testing.
- FLUSH SESSION STATUS added as an alias for FLUSH STATUS.
- FLUSH STATUS does not require any privilege (before required RELOAD).
- FLUSH GLOBAL STATUS requires RELOAD privilege.
- All global status reset moved to FLUSH GLOBAL STATUS.
- Replication semisync status variables are now reset by
FLUSH GLOBAL STATUS.
- In test cases, the only changes are:
- Replace FLUSH STATUS with FLUSH GLOBAL STATUS
- Replace FLUSH STATUS with FLUSH STATUS; FLUSH GLOBAL STATUS.
This was only done in a few tests where the test was using SHOW STATUS
for both local and global variables.
- Uptime_since_flush_status is now always provided, independent if
ENABLED_PROFILING is enabled when compiling MariaDB.
- @@global.Uptime_since_flush_status is reset on FLUSH GLOBAL STATUS
and @@session.Uptime_since_flush_status is reset on FLUSH SESSION STATUS.
- When connected, @@session.Uptime_since_flush_status is set to 0.
This task is to ensure we have a clear definition and rules of how to
repair or optimize a table.
The rules are:
- REPAIR should be used with tables that are crashed and are
unreadable (hardware issues with not readable blocks, blocks with
'unexpected data' etc)
- OPTIMIZE table should be used to optimize the storage layout for the
table (recover space for delete rows and optimize the index
structure.
- ALTER TABLE table_name FORCE should be used to rebuild the .frm file
(the table definition) and the table (with the original table row
format). If the table is from and older MariaDB/MySQL release with a
different storage format, it will convert the data to the new
format. ALTER TABLE ... FORCE is used as part of mariadb-upgrade
Here follows some more background:
The 3 ways to repair a table are:
1) ALTER TABLE table_name FORCE" (not other options).
As an alias we allow: "ALTER TABLE table_name ENGINE=original_engine"
2) "REPAIR TABLE" (without FORCE)
3) "OPTIMIZE TABLE"
All of the above commands will optimize row space usage (which means that
space will be needed to hold a temporary copy of the table) and
re-generate all indexes. They will also try to replicate the original
table definition as exact as possible.
For ALTER TABLE and "REPAIR TABLE without FORCE", the following will hold:
If the table is from an older MariaDB version and data conversion is
needed (for example for old type HASH columns, MySQL JSON type or new
TIMESTAMP format) "ALTER TABLE table_name FORCE, algorithm=COPY" will be
used.
The differences between the algorithms are
1) Will use the fastest algorithm the engine supports to do a full repair
of the table (except if data conversions are is needed).
2) Will use the storage engine internal REPAIR facility (MyISAM, Aria).
If the engine does not support REPAIR then
"ALTER TABLE FORCE, ALGORITHM=COPY" will be used.
If there was data incompatibilities (which means that FORCE was used)
then there will be a warning after REPAIR that ALTER TABLE FORCE is
still needed.
The reason for this is that REPAIR may be able to go around data
errors (wrong incompatible data, crashed or unreadable sectors) that
ALTER TABLE cannot do.
3) Will use the storage engine internal OPTIMIZE. If engine does not
support optimize, then "ALTER TABLE FORCE" is used.
The above will ensure that ALTER TABLE FORCE is able to
correct almost any errors in the row or index data. In case of
corrupted blocks then REPAIR possible followed by ALTER TABLE is needed.
This is important as mariadb-upgrade executes ALTER TABLE table_name
FORCE for any table that must be re-created.
Bugs fixed with InnoDB tables when using ALTER TABLE FORCE:
- No error for INNODB_DEFAULT_ROW_FORMAT=COMPACT even if row length
would be too wide. (Independent of innodb_strict_mode).
- Tables using symlinks will be symlinked after any of the above commands
(Independent of the setting of --symbolic-links)
If one specifies an algorithm together with ALTER TABLE FORCE, things
will work as before (except if data conversion is required as then
the COPY algorithm is enforced).
ALTER TABLE .. OPTIMIZE ALL PARTITIONS will work as before.
Other things:
- FORCE argument added to REPAIR to allow one to first run internal
repair to fix damaged blocks and then follow it with ALTER TABLE.
- REPAIR will not update frm_version if ha_check_for_upgrade() finds
that table is still incompatible with current version. In this case the
REPAIR will end with an error.
- REPAIR for storage engines that does not have native repair, like InnoDB,
is now using ALTER TABLE FORCE.
- REPAIR csv-table USE_FRM now works.
- It did not work before as CSV tables had extension list in wrong
order.
- Default error messages length for %M increased from 128 to 256 to not
cut information from REPAIR.
- Documented HA_ADMIN_XX variables related to repair.
- Added HA_ADMIN_NEEDS_DATA_CONVERSION to signal that we have to
do data conversions when converting the table (and thus ALTER TABLE
copy algorithm is needed).
- Fixed typo in error message (caused test changes).
