take MDL_SHARED_WRITE instead of MDL_SHARED_NO_READ_WRITE
for OPTIMIZE TABLE. For engines that need a stronger
lock (like MyISAM), reopen the table with
MDL_SHARED_NO_READ_WRITE.
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.
change buffer not empty
Fix: Allow not empty change buffer when innodb_force_recovery >= 5
and output only a warning to error log.
Note: Before using force recovery you should always take backup
of your database.
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.
Problem: We created more than 5 encryption keys for redo-logs.
Idea was that we do not anymore create more than one encryption
key for redo-logs but if existing checkpoint from earlier
MariaDB contains more keys, we should read all of them.
Fix: Add new encryption key to memory structure only if there
currently has none or if we are reading checkpoint from the log.
Checkpoint from older MariaDB version could contain more than
one key.
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.
Problem was that link file (.isl) is also opened using O_DIRECT
mode and if this fails the whole create table fails on internal
error.
Fixed by not using O_DIRECT on link files as they are used only
on create table and startup and do not contain real data.
O_DIRECT failures are successfully ignored for data files
if O_DIRECT is not supported by file system on used
data directory.
Analysis:
-- InnoDB has n (>0) redo-log files.
-- In the first page of redo-log there is 2 checkpoint records on fixed location (checkpoint is not encrypted)
-- On every checkpoint record there is up to 5 crypt_keys containing the keys used for encryption/decryption
-- On crash recovery we read all checkpoints on every file
-- Recovery starts by reading from the latest checkpoint forward
-- Problem is that latest checkpoint might not always contain the key we need to decrypt all the
redo-log blocks (see MDEV-9422 for one example)
-- Furthermore, there is no way to identify is the log block corrupted or encrypted
For example checkpoint can contain following keys :
write chk: 4 [ chk key ]: [ 5 1 ] [ 4 1 ] [ 3 1 ] [ 2 1 ] [ 1 1 ]
so over time we could have a checkpoint
write chk: 13 [ chk key ]: [ 14 1 ] [ 13 1 ] [ 12 1 ] [ 11 1 ] [ 10 1 ]
killall -9 mysqld causes crash recovery and on crash recovery we read as
many checkpoints as there is log files, e.g.
read [ chk key ]: [ 13 1 ] [ 12 1 ] [ 11 1 ] [ 10 1 ] [ 9 1 ]
read [ chk key ]: [ 14 1 ] [ 13 1 ] [ 12 1 ] [ 11 1 ] [ 10 1 ] [ 9 1 ]
This is problematic, as we could still scan log blocks e.g. from checkpoint 4 and we do
not know anymore the correct key.
CRYPT INFO: for checkpoint 14 search 4
CRYPT INFO: for checkpoint 13 search 4
CRYPT INFO: for checkpoint 12 search 4
CRYPT INFO: for checkpoint 11 search 4
CRYPT INFO: for checkpoint 10 search 4
CRYPT INFO: for checkpoint 9 search 4 (NOTE: NOT FOUND)
For every checkpoint, code generated a new encrypted key based on key
from encryption plugin and random numbers. Only random numbers are
stored on checkpoint.
Fix: Generate only one key for every log file. If checkpoint contains only
one key, use that key to encrypt/decrypt all log blocks. If checkpoint
contains more than one key (this is case for databases created
using MariaDB server version 10.1.0 - 10.1.12 if log encryption was
used). If looked checkpoint_no is found from keys on checkpoint we use
that key to decrypt the log block. For encryption we use always the
first key. If the looked checkpoint_no is not found from keys on checkpoint
we use the first key.
Modified code also so that if log is not encrypted, we do not generate
any empty keys. If we have a log block and no keys is found from
checkpoint we assume that log block is unencrypted. Log corruption or
missing keys is found by comparing log block checksums. If we have
a keys but current log block checksum is correct we again assume
log block to be unencrypted. This is because current implementation
stores checksum only before encryption and new checksum after
encryption but before disk write is not stored anywhere.
Make sure that on decrypt we do not try to reference
NULL pointer and if page contains undefined
FIL_PAGE_FILE_FLUSH_LSN field on when page is not
the first page or page is not in system tablespace,
clear it.
Fixes a deadlock between applier and its victim transaction.
The deadlock would manifest when a BF victim was waiting for some lock
and was signaled to rollback, and the same time its wait
timeout expired. In such cases the victim would return from
lock_wait_suspend_thread() with error DB_LOCK_WAIT_TIMEOUT, as opposed to
DB_DEADLOCK. As a result only the last statement of the victim would rollback,
and eventually it would deadlock with the applier.
