i_s_innodb_buffer_page_get_info(): Do not read the buffer block frame
contents of read-fixed blocks, because it may be invalid or
uninitialized. When we are going to decompress or read a block, we
will put it into buf_pool->page_hash and buf_pool->LRU, read-fix the
block and release the mutexes for the duration of the reading or
decompression.
rb#2500 approved by Jimmy Yang
USING THE PLUGIN INTERFACE.
ISSUE: No support for floating-point plugin
system variables.
SOLUTION: Allowing plugins to define and expose floating-point
system variables of type double. MYSQL_SYSVAR_DOUBLE
and MYSQL_THDVAR_DOUBLE are added.
ISSUE: Fractional part of the def, min, max values of system
variables are ignored.
SOLUTION: Adding functions that are used to store the raw
representation of a double in the raw bits of unsigned
longlong in a way that the binary representation
remains the same.
ESCAPED WITH BACKSLASH
Problem:
When the CREATE TABLE statement used COMMENTS with escape sequences like
'foo\'s', InnoDB did not parse is correctly when trying to extract the
foreign key information. Because of this, the foreign keys specified
in the CREATE TABLE statement were not created.
Solution:
Make the InnoDB internal parser aware of escape sequences.
rb#2457 approved by Kevin.
INSERT BUFFER MERGE
Problem:
When the record is merged from the change buffer to the actual page,
in a particular condition, it is assumed that the deleted rec will
be re-used by the inserted rec. With this assumption the lock is
restored on the pointer to the deleted rec itself, thinking that
it is pointing to the newly inserted rec.
Solution:
Just before restoring the lock, update the rec pointer to point
to the newly inserted record. An assert has been added to verify
this. This assert will fail without the fix and will pass with
the fix.
rb#2449 in review by Marko and Jimmy
INNODB_FAST_SHUTDOWN IS 2
Problem:
When innodb_fast_shutdown is set to 2 and the master thread enters
flush loop, under some circumstances it will not be able to exit it.
This may lead to a shutdown hanging.
This is happening because of the following:
1. In the flush_loop block of code, if the srv_fast_shutdown is
equal to 2 (very fast shutdown), then we do not flush dirty
pages in buffer pool to disk.
2. In the same flush_loop block of code, if the number of dirty
pages is more than user specified limit, we go to step 1.
This results in infinite loop.
Solution:
When we are in the process of doing a very fast shutdown, don't
do step 2 above.
rb#2328 approved by Inaam.
When a record contains no user data bytes (such as when the PRIMARY
KEY is an empty string and all secondary index fields are NULL or the
empty string), page_zip_decompress() could fail to set the record
heap_no correctly.
page_zip_decompress_node_ptrs(), page_zip_decompress_sec(),
page_zip_decompress_clust(): Set heap_no also at the end of the
compressed data stream.
rb#2448 approved by Jimmy Yang and Inaam Rana
AFTER A ROW IS READ
Approved by: Sunny Bains rb://2425
Don't release concurrency tickets when asked to release
btr_search_latch. This is a 5.5 only bug. It is already
fixed in 5.6 upwards.
== Analysis ==
Both change buffer pages and on-disk indexes pages are marked as
FIL_PAGE_INDEX. So all ibuf index pages will classify as INDEX with NULL
table_name and index_name.
== Solution ==
A new page type for ibuf data pages named I_S_PAGE_TYPE_IBUF is defined. All
these pages whose index_id equal (DICT_IBUF_ID_MIN + IBUF_SPACE_ID) will
classify as IBUF_DATA instead of INDEX in INNODB_BUFFER_PAGE
and INNODB_BUFFER_PAGE_LRU.
This fix is only for IS reporting, both on-disk and buffer pool structures
keep unchanged.
Approved by both Marko and Jimmy. rb#2334
innobase_convert_to_filename_charset() was by mistake kept within
the conditional compilation of UNIV_COMPILE_TEST_FUNCS. Now placing
the function out of UNIV_COMPILE_TEST_FUNCS. Also, removed the
unnecessary log message (as in 5.6+).
TRANSACTION ROLLBACK
Problem:
=======
"prepare_commit_mutex" is acquired during "innobase_xa_prepare"
and it is freed only in "innobase_commit". After prepare,
if the commit operation fails the transaction is rolled back
but the mutex is not released.
Analysis:
========
During transaction commit process transaction is prepared and
the "prepare_commit_mutex" is acquired to preserve the order
of commit. After prepare write to binlog is initiated.
File: sql/handler.cc
if (error || (is_real_trans && xid &&
-----> (error= !(cookie= tc_log->log_xid(thd, xid)))))
{
ha_rollback_trans(thd, all);
In the above code "tc_log->log_xid" operation fails.
When the write to binlog fails the transaction is rolled back
with out freeing the mutex. A subsequent "INSERT" operation
tries to acquire the same mutex during its commit process
and the server aborts.
Fix:
===
"prepare_commit_mutex" is freed during "innobase_rollback".
Bug #16754901 PARS_INFO_FREE NOT CALLED IN DICT_CREATE_ADD_FOREIGN_TO_DICTIONARY
Problem:
There are two situations here. The constraint name is explicitly
given by the user and the constraint name is automatically generated
by InnoDB. In the case of generated constraint name, it is formed by
adding table name as prefix. The table names are stored internally in
my_charset_filename. In the case of constraint name explicitly given
by the user, it is stored in UTF8 format itself. So, in some
situations the constraint name is in utf8 and in some situations it is
in my_charset_filename format. Hence this problem.
Solution:
Always store the foreign key constraint name in UTF-8 even when
automatically generated.
Bug #16754901 PARS_INFO_FREE NOT CALLED IN DICT_CREATE_ADD_FOREIGN_TO_DICTIONARY
Problem:
There was a memory leak in the function dict_create_add_foreign_to_dictionary().
The allocated pars_info_t object is not freed in the error code path.
Solution:
Allocate the pars_info_t object after the error checking.
rb#2368 in review
eliminate a race condition over recv_sys->n_addrs which might result in a database corruption
in recovery, without reporting a recovery error.
recv_recover_page_func(): move the code segment that decrements recv_sys->n_addrs
to the end of the function, after the call to mtr_commit()
rb://2282 approved by Inaam
After a clean shutdown, InnoDB will not check the *.ibd file headers,
for maximum performance. This is unchanged before and after this
patch.
What this fix addresses is the case when crash recovery is
needed. Previously, InnoDB could load a corrupted tablespace file.
buf_page_is_corrupted(): Add the parameter check_lsn.
fil_check_first_page(): New function, to perform a consistency check
on the first page of a file. This can be overridden by setting
innodb_force_recovery.
fil_read_first_page(), fil_open_single_table_tablespace(),
fil_load_single_table_tablespace(): Invoke fil_check_first_page().
open_or_create_data_files(): Check the status of
fil_open_single_table_tablespace().
rb#2352 approved by Jimmy Yang
OPENING MISSING PARTITION
In the ha_innobase::open() call, for normal tables, there is no retry logic.
But for partitioned tables, there is a retry logic introduced as fix for:
http://bugs.mysql.com/bug.php?id=33349https://support.mysql.com/view.php?id=21080
The Bug#33349, does not provide sufficient information to analyze the original
problem. The original problem reported by bug#33349 is also minor (just an
annoyance and no loss of functionality). Most importantly, the retry logic
has been introduced without any associated test case.
So we are removing the retry logic for partitioned tables. When the original
problem occurs, a different solution will be explored.
TABLE/KEY RELATIONS
The DICT_FK_MAX_RECURSIVE_LOAD was reduced from 250 to 33 in rb#2058.
But in optimized build, this recursive depth is still too deep and
resulted in stack overflow. So reducing this depth to 20 now.
TABLE/KEY RELATIONS
Problem:
When there are many tables, linked together through the foreign key
constraints, then loading one table will recursively open other tables. This
can sometimes lead to thread stack overflow. In such situations the server
will exit.
I see the stack overflow problem when the thread_stack is 196608 (the default
value for 32-bit systems). I don't see the problem when the thread_stack is
set to 262144 (the default value for 64-bit systems).
Solution:
Currently, in InnoDB, there is a macro DICT_FK_MAX_RECURSIVE_LOAD which defines
the maximum number of tables that will be loaded recursively because of foreign
key relations. This is currently set to 250. We can reduce this number to 33
(anything more than 33 does not solve the problem for the default value). We
can keep it small enough so that thread stack overflow does not happen for the
default values. Reducing the DICT_FK_MAX_RECURSIVE_LOAD will not affect the
functionality of InnoDB. The tables will eventually be loaded.
rb#2058 approved by Marko
TABLE/KEY RELATIONS
Problem:
When there are many tables, linked together through the foreign key
constraints, then loading one table will recursively open other tables. This
can sometimes lead to thread stack overflow. In such situations the server
will exit.
I see the stack overflow problem when the thread_stack is 196608 (the default
value for 32-bit systems). I don't see the problem when the thread_stack is
set to 262144 (the default value for 64-bit systems).
Solution:
Currently, in InnoDB, there is a macro DICT_FK_MAX_RECURSIVE_LOAD which defines
the maximum number of tables that will be loaded recursively because of foreign
key relations. This is currently set to 250. We can reduce this number to 33
(anything more than 33 does not solve the problem for the default value). We
can keep it small enough so that thread stack overflow does not happen for the
default values. Reducing the DICT_FK_MAX_RECURSIVE_LOAD will not affect the
functionality of InnoDB. The tables will eventually be loaded.
rb#2058 approved by Marko
UPDATES
After checking that the table has changed too much in
row_update_statistics_if_needed() and calling dict_update_statistics(),
also check if the same condition holds after acquiring the table stats
latch. This is to avoid multiple threads concurrently entering and
executing the stats update code.
Approved by: Marko (rb:2186)
FREED LOCK
ANALYIS
-------
In 5.5 code the lock_rec_block_validate() is called after releasing
the kernel mutex. There is a chance that the lock might be invalid so,
we are getting the valgrind error on invalid read on lock->index.
FIX
---
Fix would be to copy the lock->index when we are holding the kernel mutex
and then pass it to the lock_rec_block_validate(). This implementation
is present in 5.1 code.
[ Approved by sunny rb.no.oracle.com/rb/r/2152/ ]
IBUF, FREE SPACE MANAGEMENT
ibuf_merge_or_delete_for_page(): Declare the user index page latched
for UNIV_SYNC_DEBUG after opening the change buffer cursor. This
should avoid the bogus latching order violation.
ibuf_delete_rec(): Add assertions to the callers, checking that the
mini-transaction was committed when the function returned TRUE. This
is a non-functional change, just clarifying the code.
rb#2136 approved by Kevin Lewis
For a fresh insert, page_zip_available() was counting some fields twice.
In the worst case, the compressed page size grows by PAGE_ZIP_DIR_SLOT_SIZE
plus the size of the record that is being inserted. The size of the record
already includes the fields that will be stored in the uncompressed portion
of the compressed page.
page_zip_get_trailer_len(): Remove the output parameter entry_size,
because no caller is interested in it.
page_zip_max_ins_size(), page_zip_available(): Assume that the page grows
by PAGE_ZIP_DIR_SLOT_SIZE and the record size (which includes the fields
that would be stored in the uncompressed portion of the page).
rb#2169 approved by Sunny Bains
MEM_HEAP_CREATE_BLOCK()
PROBLEM
-------
If we give start mysqld with the option --innodb_log_buffer_size=50GB
,then mem_area_alloc() function fails to allocate memory and returns
NULL.In debug version we assert at this point,but there is no check in
release version and we get a segmentation fault.
FIX
---
Added a log message saying that we are unable to allocate memory.
After this message we assert.
[Approved by Kevin http://rb.no.oracle.com/rb/r/2065 ]
INSERT WITH SAME VALUES
Problem:
When a transaction is in READ COMMITTED isolation level, gap locks are still
taken in the secondary index, when row is inserted. This happens when the
secondary index is scanned for duplicate.
The function row_ins_scan_sec_index_for_duplicate() always calls the
function row_ins_set_shared_rec_lock() with LOCK_ORDINARY irrespective of
the transaction isolation level.
Solution:
The function row_ins_scan_sec_index_for_duplicate() calls the
function row_ins_set_shared_rec_lock() with LOCK_ORDINARY or
LOCK_REC_NOT_GAP based on the transaction isolation level.
rb://2035 approved by Krunal and Marko
Before this fix, the command
SHOW ENGINE PERFORMANCE_SCHEMA STATUS
could report wrong amount of memory allocated,
when the amount of memory used exceeds 4GB.
The problem is that size computations are not done using size_t,
so that overflows do occur, truncating the results.
This fix compute memory sizes properly with size_t.
Tested manually.
No test script provided, as the script would need to allocate too much
memory for the test.
This is a deadlock that will also be fixed in the server by
Bug #11844915 - HANG IN THDVAR MUTEX ACQUISITION.
So this is a simple alternate method of fixing the same problem,
but from within InnoDB.
The simple change is to make rename table start a transaction
before locking dict_sys->mutex since thd_supports_xa() can call
THDVAR which can lock a mutex, LOCK_global_system_variables, that
is used in the server by many other activities. At least one of
those, sys_var::update(), can call back into InnoDB and try to
lock dict_sys->mutex while holding LOCK_global_system_variables.
The other bug fix for 11844915 eliminates the use of
LOCK_global_system_variables for calls to THDVAR.
Approved by marko in http://rb.no.oracle.com/rb/r/2000/
page_zip_compress_node_ptrs(): Do not attempt to invoke deflate() with
c_stream->avail_in, because it will result in Z_BUF_ERROR (and
page_zip_compress() failure and unnecessary further splits of the node
pointer page). A node pointer record can have empty payload, provided
that all key fields are empty.
Approved by Jimmy Yang
