Followup from 5.5 patch. Removing memory barriers on intel is wrong as
this doesn't prevent the compiler and/or processor from reorganizing reads
before the mutex release. Forcing a memory barrier before reading the waiters will
guarantee that no speculative reading takes place.
Fix memory barrier issues on releasing mutexes. We must have a full
memory barrier between releasing a mutex lock and reading its waiters.
This prevents us from missing to release waiters due to reading the
number of waiters speculatively before releasing the lock. If threads
try and wait between us reading the waiters count and releasing the
lock, those threads might stall indefinitely.
Also, we must use proper ACQUIRE/RELEASE semantics for atomic
operations, not ACQUIRE/ACQUIRE.
commit ef92aaf9ec
Author: Jan Lindström <jan.lindstrom@mariadb.com>
Date: Wed Jun 22 22:37:28 2016 +0300
MDEV-10083: Orphan ibd file when playing with foreign keys
Analysis: row_drop_table_for_mysql did not allow dropping
referenced table even in case when actual creating of the
referenced table was not successfull if foreign_key_checks=1.
Fix: Allow dropping referenced table even if foreign_key_checks=1
if actual table create returned error.
Analysis: row_drop_table_for_mysql did not allow dropping
referenced table even in case when actual creating of the
referenced table was not successfull if foreign_key_checks=1.
Fix: Allow dropping referenced table even if foreign_key_checks=1
if actual table create returned error.
Bug #79636: CACHE_LINE_SIZE should be 128 on AArch64
Bug #79637: Hard-coded cache line size
Bug #79638: Reconcile CACHE_LINE_SIZE with CPU_LEVEL1_DCACHE_LINESIZE
Bug #79652: Suspicious padding in srv_conc_t
- changed CPU_LEVEL1_DCACHE_LINESIZE to default to 128 bytes on POWER
and AArch64 architectures in cases when no value could be detected
by CMake using getconf
- changed CACHE_LINE_SIZE definition in ut0counter.h to be an alias of
CPU_LEVEL1_DCACHE_LINESIZE
- changed a number of hard-coded 64-byte cache line size values in the
InnoDB code
- fixed insufficient padding for srv_conc members in srv0conc.cc
Ported to Mariadb by Daniel Black <daniel.black@au.ibm.com>
Added s390 cache size of 256 at same time.
MySQL 5.6 do not work with MariaDB 10.1
Analysis: Problem is that tablespace flags bit DATA_DIR
is on different position on MySQL 5.6 compared to
MariaDB 10.1.
Fix: If we detect that there is difference between dictionary
flags and tablespace flags we remove DATA_DIR flag and compare
again. Remote tablespace is tried to locate even in case
when DATA_DIR flag is not set.
Analysis: When pages in doublewrite buffer are analyzed compressed
pages do not have correct checksum.
Fix: Decompress page before checksum is compared. If decompression
fails we still check checksum and corrupted pages are found.
If decompression succeeds, page now contains the original
checksum.
Problem was that in-place online alter table was used on a table
that had mismatch between MySQL frm file and InnoDB data dictionary.
Fixed so that traditional "Copy" method is used if the MySQL frm
and InnoDB data dictionary is not consistent.
Using __ppc_get_timebase will translate to mfspr instruction
The mfspr instruction will block FXU1 until complete but the other
Pipelines are available for execution of instructions from other
SMT threads on the same core.
The latency time to read the timebase SPR is ~10 cycles.
So any impact on other threads is limited other FXU1 only instructions
(basically other mfspr/mtspr ops).
Suggested by Steven J. Munroe, Linux on Power Toolchain Architect,
Linux Technology Center
IBM Corporation
Bug#18842925 : SET THREAD PRIORITY IN INNODB MUTEX SPINLOOP
Like "pause" instruction for hyper-threading at Intel CPUs,
POWER has special instructions only for hinting priority of hardware-threads.
Approved by Sunny in rb#6256
Backport of the 5.7 fix - c92102a6ef
(excluded cache line size patch)
Suggestion by Stewart Smith
UT_RELAX_CPU(): Use a compiler barrier.
ut_delay(): Remove the dummy global variable ut_always_false.
RB: 11399
Reviewed-by: Jimmy Yang <jimmy.yang@oracle.com>
Backported from MySQL-5.7 - patch 5e3efb0396
Suggestion by Stewart Smith
Make sure that we read all possible encryption keys from checkpoint
and if log block checksum does not match, print all found
checkpoint encryption keys.
