We introduce the following settable Boolean global variables:
innodb_log_file_write_through: Whether writes to ib_logfile0 are
write-through (disabling any caching, as in O_SYNC or O_DSYNC).
innodb_data_file_write_through: Whether writes to any InnoDB data files
(including the temporary tablespace) are write-through.
innodb_data_file_buffering: Whether the file system cache is enabled
for InnoDB data files.
All these parameters are OFF by default, that is, the file system cache
will be disabled, but any hardware caching is enabled, that is,
explicit calls to fsync(), fdatasync() or similar functions are needed.
On systems that support FUA it may make sense to enable write-through,
to avoid extra system calls.
If the deprecated read-only start-up parameter is set to one of the
following values, then the values of the 4 Boolean flags (the above 3
plus innodb_log_file_buffering) will be set as follows:
O_DSYNC:
innodb_log_file_write_through=ON, innodb_data_file_write_through=ON,
innodb_data_file_buffering=OFF, and
(if supported) innodb_log_file_buffering=OFF.
fsync, littlesync, nosync, or (Microsoft Windows specific) normal:
innodb_log_file_write_through=OFF, innodb_data_file_write_through=OFF,
and innodb_data_file_buffering=ON.
Note: fsync() or fdatasync() will only be disabled if the separate
parameter debug_no_sync (in the code, my_disable_sync) is set.
In mariadb-backup, the parameter innodb_flush_method will be ignored.
The Boolean parameters can be modified by SET GLOBAL while the
server is running. This will require reopening the ib_logfile0
or all currently open InnoDB data files.
We will open files straight in O_DSYNC or O_SYNC mode when applicable.
Data files we will try to open straight in O_DIRECT mode when the
page size is at least 4096 bytes. For atomically creating data files,
we will invoke os_file_set_nocache() to enable O_DIRECT afterwards,
because O_DIRECT is not supported on some file systems. We will also
continue to invoke os_file_set_nocache() on ib_logfile0 when
innodb_log_file_buffering=OFF can be fulfilled.
For reopening the ib_logfile0, we use the same logic that was developed
for online log resizing and reused for updates of
innodb_log_file_buffering.
Reopening all data files is implemented in the new function
fil_space_t::reopen_all().
Reviewed by: Vladislav Vaintroub
Tested by: Matthias Leich
setup_boot_args(), setup_client_args(), setup_args() traversing
datastructures on each invocation. Even if performance is not
important to perl script (though it definitely saves some CO2), this
nonetheless provokes some code-reading questions. Reading and
debugging such code is not convenient.
The better way is to prepare all the data in advance in an easily
readable form as well as do the validation step before any further
processing.
Use mtr_report() instead of die() like the other code does.
TODO: do_args() does even more data processing magic. Prepare that
data according the above strategy in advance in pre_setup() if possible.
There is a server startup option --gdb a.k.a. --debug-gdb that requests
signals to be set for more convenient debugging. Most notably, SIGINT
(ctrl-c) will not be ignored, and you will be able to interrupt the
execution of the server while GDB is attached to it.
When we are debugging, the signal handlers that would normally display
a terse stack trace are useless.
When we are debugging with rr, the signal handlers may interfere with
a SIGKILL that could be sent to the process by the environment, and ruin
the rr replay trace, due to a Linux kernel bug
https://lkml.org/lkml/2021/10/31/311
To be able to diagnose bugs in kill+restart tests, we may really need
both a trace before the SIGKILL and a trace of the failure after a
subsequent server startup. So, we had better avoid hitting the problem
by simply not installing those signal handlers.
Test times when using --valgrind are now 4 hours and server start/shutdown
time 180 seconds.
The whole test suite time is caped at 1 day instead of 7 days
Reviewer: Monty
Until https://github.com/rr-debugger/rr/issues/2613
has been addressed, ./mtr --rr will fail to start up the
server if it has been configured with liburing.
To make the ./mtr --rr option work out of the box, we will
disable native asynchronous I/O.
Note: libaio never worked under rr, but it failed more gracefully:
the emulated io_setup() call would always return an error.
use _RR_TRACE_DIR=dir instead of -o dir, as the former can store
multiple traces in dir (if, e.g., the test restarts mysqld)
suppress uninitialized warning when $exe is undefined (--manual-XXX)
add a new "debugger" to mtr, that runs the executable
under valgrind in gdb. valgrind pid is auto-detected,
but the delay (sleep) and vgdb path are hard-coded for now
"debugger" is anything that wraps execution of a target
binary (mysqld or mysqltest). Currently the list includes:
gdb, ddd, dbx, lldb, valgrind, strace, ktrace, rr,
devenv, windbg, vsjitdebugger.
for every debugger xxx, mtr will recognize four options:
--xxx, --boot-xxx, --manual-xxx, --client-xxx.
They all support an optional "=string" argument. String
being a semicolon-separated list of commands (e.g. for gdb)
or one (not semicolon-separated) command line of options
(e.g. for valgrind). Or both (e.g. --gdb='-quiet -nh;info files'
In embedded both --xxx and --client-xxx work.
Functionality changed/removed:
* --rr-args is gone
* --rr-dir is gone
* --manual-debug is gone
* --debugger={devenv|vc|windbg|vc_express|vsjitdebugger} is gone
* --strace-option is gone
* --stracer={strace|ktrace} is gone
* --valgrind only enables it for the server, not for everything
* --valgrind-all is gone
* --valgrind-mysqltest is gone
* --valgrind-mysqld is gone
* --valgrind-options is gone
* --valgrind-option is gone
* --valgrind-path is gone
* --callgrind is gone
* one cannot combine --valgrind --gdb anymore
* valgrind report doesn't add a fake test line to the output
* vc and vcexpress on windows are no longer supported