My Ubuntu 22.04 server is suddenly telling me that "The redo log file "./#innodb_redo/#ib_redo0 size 23289856 is not a multiple of innodb_page_size." My innodb_page_size is 16K, so the error is correct, but I can't seem to find any advice on how to fix it. I tried moving ib_redo0 out of the way but that didn't help. Any ideas?
I also encountered this issue. It appeared to be specific to using ZFS on Ubuntu, in my case it was during an upgrade to MYSQL 8.0.30-0ubuntu0.20.04.2.
Following details in this Ubuntu issue report and this MySQL issue report I was able to come up with a solution that worked in my environment.
There are 3 commands below to be ran as root or with sudo. You should replace 8192 in the first with the result of <broken_file_size> % <default_page_size>. The default page size is usually 16384 unless modified.
You may need to replace the #ib_redo0 part of the second command with the broken file reported in the error message.
These commands are intended to pad out the reportedly invalid file with zeros.
Perform a backup before running!
# Gather required zeros to append
# Will create a "zeros" file in the current directory
# This has been calculated based upon 23289856 % 16384 = 8192 or <broken_file_size> % <default_page_size>
dd if=/dev/zero bs=1 count=8192 of=./zeros
# Append zeroes to invalid file
cat zeros >> /var/lib/mysql/#innodb_redo/#ib_redo0
# Restart MySQL
systemctl restart mysql.service
I'd be wary of remaining on ZFS, even if the above fixes things, for the sake of potentially hitting the same issue again.
I had the same Problem in a LXD Container running on ZFS. I had to move it to a different type of storage-pool, e.g. Directory or BTRFS.
After that the solution of #DanBrown worked for me too.
Thank you.
Now I make low level bare-metal tool for RPi.
And I need to get Secure Configuration Register value.
I wrote the following instruction mrc p15, 0, r0, c1, c1, 0 to get it.
But CPU goes into Undefined Exception Mode and CPSR value is 0x600001DB.
Instruction of reading SCR value is the first instruction being executed by CPU.
I'd read ARM1176JZF-S TRM r0p7 several times but I've not found any restriction on using SCR reading instruction except being CPU in the Secure Privileged Mode but according to TRM this CPU starts from Secure Privileged Mode. If to be more concrete the initial mode is Secure Supervisor Mode.
I use the following command to execute code with QEMU
qemu-system-arm -cpu arm1176 -M versatilepb -m 256 -nographic -kernel start.elf -s -S -monitor stdio
I can't understand what I overlooked?
QEMU's versatilepb board does not support TrustZone: it creates a CPU with that feature disabled.
Other QEMU board models do support TZ, if you want to play with it: for instance vexpress-a9, vexpress-a15 and raspi2; also "virt", if you pass -machine secure=on on the QEMU command line.
mysql config my.ini default query_cache_type=0 .
I have already set sql_query_pre = SET SESSION query_cache_type=OFF in sphinx.conf.I think it is not good to turn cache while indexing.But sphinx still asking me to turn on cache...
error detail:
win7 x64, sphinx 2.1.7
I:\sphinx\bin>I:\sphinx\bin\indexer.exe --all --config I:\sphinx\bin\sphinx.conf
Sphinx 2.1.7-id64-release (r4638)
Copyright (c) 2001-2014, Andrew Aksyonoff
Copyright (c) 2008-2014, Sphinx Technologies Inc (http://sphinxsearch.com)
using config file 'I:\sphinx\bin\sphinx.conf'...
indexing index 'test1'...
ERROR: index 'test1': sql_query_pre[1]: Query cache is disabled; restart the server with query_cache_type=1 to enable it
(DSN=mysql://root:***#localhost:3306/test).
total 0 docs, 0 bytes
total 0.018 sec, 0 bytes/sec, 0.00 docs/sec
skipping non-plain index 'rt'...
total 0 reads, 0.000 sec, 0.0 kb/call avg, 0.0 msec/call avg
total 0 writes, 0.000 sec, 0.0 kb/call avg, 0.0 msec/call avg
The 'message' you are receiving is coming from mysql - not from sphinx. indexer just runs the commands as provided and reports/uses the results.
Basically mysql is telling yo the query cache is already disabled. its not enabled globally.
So trying to turn if off for just the (indexing) session, fails, because its not on. If its not enabled in teh first place you cant disable it!
http://www.big.info/2013/04/error-code-1651-query-cache-is-disabled.html
Its telling you NEED to turn it on globally first, before you are ABLE to turn if off.
Maybe mysql could just silently fail to turn it off, rather than giving an error, but thats a different story.
I had a case where I was seeing this error, and it was actually preventing the indexer --all command from generating indices. I went to the XAMPP Control Panel and clicked on the Config button for the MySQL module. This opened the file my.ini in Notepad. I added the following line to the [mysqld] section in the file:
query_cache_type = 1
Then I restarted the MySQL service. The value of query_cache_type was now displayed as ON, and the indexer --all command successfully generated indices.
I am trying to execute a shell command from within mysql (from within a procedure or a trigger or the command line for mysql).
I have added lib_mysqludf_sys to the mysql plugins and created the functions that are available with the library. (the library) home page
The library has 5 functions.
sys_set - to set $PATH - this works and stores the $PATH which i can later check.
sys_get - to get the stored value of $PATH - this also works and returns the value that I have stored.
sys_exec - to execute a command in the system and return the exit code.
sys_eval - to execute a command in the system and return the standard output.
lib_mysqludf_sys_info - return the current version of the library - this also works.
I need sys_exec and sys_eval to work correctly.
I think I have found the problem in my search but cannot solve it.
mysql is limited by apparmor and is not granted access to execute system commands by the default apparmor profile. I have tried the commands in the documentation to disable a single profile, disable the framework, putting all profiles except one into enforce mode and putting all profiles in complain mode. Nothing works. the command
sudo apparmor_status
always gives me the same output.
20 profiles are loaded.
20 profiles are in enforce mode.
/opt/extras.ubuntu.com/unity-lens-askubuntu/unity-askubuntu-daemon
/sbin/dhclient
/usr/bin/evince
/usr/bin/evince-previewer
/usr/bin/evince-previewer//launchpad_integration
/usr/bin/evince-previewer//sanitized_helper
/usr/bin/evince-thumbnailer
/usr/bin/evince-thumbnailer//sanitized_helper
/usr/bin/evince//launchpad_integration
/usr/bin/evince//sanitized_helper
/usr/lib/NetworkManager/nm-dhcp-client.action
/usr/lib/connman/scripts/dhclient-script
/usr/lib/cups/backend/cups-pdf
/usr/lib/lightdm/lightdm/lightdm-guest-session-wrapper
/usr/lib/telepathy/mission-control-5
/usr/lib/telepathy/telepathy-*
/usr/sbin/cupsd
/usr/sbin/mysqld
/usr/sbin/tcpdump
/usr/share/gdm/guest-session/Xsession
0 profiles are in complain mode.
5 processes have profiles defined.
5 processes are in enforce mode.
/sbin/dhclient (2537)
/usr/lib/telepathy/mission-control-5 (2709)
/usr/sbin/cupsd (12245)
/usr/sbin/cupsd (12250)
/usr/sbin/mysqld (12675)
0 processes are in complain mode.
0 processes are unconfined but have a profile defined.
Please tell me how I could disable apparmor or change the profile for mysql so that it has access to executing system commands.
The reason I am doing all this is so that I can execute a system command when somethings happen in the DB (via a DB trigger), if you have suggestion for some other ways in which this can be easily implemented then please mention those too.
Thanks.
managed to get this working. First put apparmor in complain mode for the necessary profiles then used apparmor's interactive tools (aa-genprof/aa-logprof) to configure the profile for mysqld
How can I trace MySQL queries on my Linux server as they happen?
For example I'd love to set up some sort of listener, then request a web page and view all of the queries the engine executed, or just view all of the queries being run on a production server. How can I do this?
You can log every query to a log file really easily:
mysql> SHOW VARIABLES LIKE "general_log%";
+------------------+----------------------------+
| Variable_name | Value |
+------------------+----------------------------+
| general_log | OFF |
| general_log_file | /var/run/mysqld/mysqld.log |
+------------------+----------------------------+
mysql> SET GLOBAL general_log = 'ON';
Do your queries (on any db). Grep or otherwise examine /var/run/mysqld/mysqld.log
Then don't forget to
mysql> SET GLOBAL general_log = 'OFF';
or the performance will plummet and your disk will fill!
You can run the MySQL command SHOW FULL PROCESSLIST; to see what queries are being processed at any given time, but that probably won't achieve what you're hoping for.
The best method to get a history without having to modify every application using the server is probably through triggers. You could set up triggers so that every query run results in the query being inserted into some sort of history table, and then create a separate page to access this information.
Do be aware that this will probably considerably slow down everything on the server though, with adding an extra INSERT on top of every single query.
Edit: another alternative is the General Query Log, but having it written to a flat file would remove a lot of possibilities for flexibility of displaying, especially in real-time. If you just want a simple, easy-to-implement way to see what's going on though, enabling the GQL and then using running tail -f on the logfile would do the trick.
Even though an answer has already been accepted, I would like to present what might even be the simplest option:
$ mysqladmin -u bob -p -i 1 processlist
This will print the current queries on your screen every second.
-u The mysql user you want to execute the command as
-p Prompt for your password (so you don't have to save it in a file or have the command appear in your command history)
i The interval in seconds.
Use the --verbose flag to show the full process list, displaying the entire query for each process. (Thanks, nmat)
There is a possible downside: fast queries might not show up if they run between the interval that you set up. IE: My interval is set at one second and if there is a query that takes .02 seconds to run and is ran between intervals, you won't see it.
Use this option preferably when you quickly want to check on running queries without having to set up a listener or anything else.
Run this convenient SQL query to see running MySQL queries. It can be run from any environment you like, whenever you like, without any code changes or overheads. It may require some MySQL permissions configuration, but for me it just runs without any special setup.
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE COMMAND != 'Sleep';
The only catch is that you often miss queries which execute very quickly, so it is most useful for longer-running queries or when the MySQL server has queries which are backing up - in my experience this is exactly the time when I want to view "live" queries.
You can also add conditions to make it more specific just any SQL query.
e.g. Shows all queries running for 5 seconds or more:
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE COMMAND != 'Sleep' AND TIME >= 5;
e.g. Show all running UPDATEs:
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE COMMAND != 'Sleep' AND INFO LIKE '%UPDATE %';
For full details see: http://dev.mysql.com/doc/refman/5.1/en/processlist-table.html
strace
The quickest way to see live MySQL/MariaDB queries is to use debugger. On Linux you can use strace, for example:
sudo strace -e trace=read,write -s 2000 -fp $(pgrep -nf mysql) 2>&1
Since there are lot of escaped characters, you may format strace's output by piping (just add | between these two one-liners) above into the following command:
grep --line-buffered -o '".\+[^"]"' | grep --line-buffered -o '[^"]*[^"]' | while read -r line; do printf "%b" $line; done | tr "\r\n" "\275\276" | tr -d "[:cntrl:]" | tr "\275\276" "\r\n"
So you should see fairly clean SQL queries with no-time, without touching configuration files.
Obviously this won't replace the standard way of enabling logs, which is described below (which involves reloading the SQL server).
dtrace
Use MySQL probes to view the live MySQL queries without touching the server. Example script:
#!/usr/sbin/dtrace -q
pid$target::*mysql_parse*:entry /* This probe is fired when the execution enters mysql_parse */
{
printf("Query: %s\n", copyinstr(arg1));
}
Save above script to a file (like watch.d), and run:
pfexec dtrace -s watch.d -p $(pgrep -x mysqld)
Learn more: Getting started with DTracing MySQL
Gibbs MySQL Spyglass
See this answer.
Logs
Here are the steps useful for development proposes.
Add these lines into your ~/.my.cnf or global my.cnf:
[mysqld]
general_log=1
general_log_file=/tmp/mysqld.log
Paths: /var/log/mysqld.log or /usr/local/var/log/mysqld.log may also work depending on your file permissions.
then restart your MySQL/MariaDB by (prefix with sudo if necessary):
killall -HUP mysqld
Then check your logs:
tail -f /tmp/mysqld.log
After finish, change general_log to 0 (so you can use it in future), then remove the file and restart SQL server again: killall -HUP mysqld.
I'm in a particular situation where I do not have permissions to turn logging on, and wouldn't have permissions to see the logs if they were turned on. I could not add a trigger, but I did have permissions to call show processlist. So, I gave it a best effort and came up with this:
Create a bash script called "showsqlprocesslist":
#!/bin/bash
while [ 1 -le 1 ]
do
mysql --port=**** --protocol=tcp --password=**** --user=**** --host=**** -e "show processlist\G" | grep Info | grep -v processlist | grep -v "Info: NULL";
done
Execute the script:
./showsqlprocesslist > showsqlprocesslist.out &
Tail the output:
tail -f showsqlprocesslist.out
Bingo bango. Even though it's not throttled, it only took up 2-4% CPU on the boxes I ran it on. I hope maybe this helps someone.
From a command line you could run:
watch --interval=[your-interval-in-seconds] "mysqladmin -u root -p[your-root-pw] processlist | grep [your-db-name]"
Replace the values [x] with your values.
Or even better:
mysqladmin -u root -p -i 1 processlist;
This is the easiest setup on a Linux Ubuntu machine I have come across. Crazy to see all the queries live.
Find and open your MySQL configuration file, usually /etc/mysql/my.cnf on Ubuntu. Look for the section that says “Logging and Replication”
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
log = /var/log/mysql/mysql.log
Just uncomment the “log” variable to turn on logging. Restart MySQL with this command:
sudo /etc/init.d/mysql restart
Now we’re ready to start monitoring the queries as they come in. Open up a new terminal and run this command to scroll the log file, adjusting the path if necessary.
tail -f /var/log/mysql/mysql.log
Now run your application. You’ll see the database queries start flying by in your terminal window. (make sure you have scrolling and history enabled on the terminal)
FROM http://www.howtogeek.com/howto/database/monitor-all-sql-queries-in-mysql/
Check out mtop.
I've been looking to do the same, and have cobbled together a solution from various posts, plus created a small console app to output the live query text as it's written to the log file. This was important in my case as I'm using Entity Framework with MySQL and I need to be able to inspect the generated SQL.
Steps to create the log file (some duplication of other posts, all here for simplicity):
Edit the file located at:
C:\Program Files (x86)\MySQL\MySQL Server 5.5\my.ini
Add "log=development.log" to the bottom of the file. (Note saving this file required me to run my text editor as an admin).
Use MySql workbench to open a command line, enter the password.
Run the following to turn on general logging which will record all queries ran:
SET GLOBAL general_log = 'ON';
To turn off:
SET GLOBAL general_log = 'OFF';
This will cause running queries to be written to a text file at the following location.
C:\ProgramData\MySQL\MySQL Server 5.5\data\development.log
Create / Run a console app that will output the log information in real time:
Source available to download here
Source:
using System;
using System.Configuration;
using System.IO;
using System.Threading;
namespace LiveLogs.ConsoleApp
{
class Program
{
static void Main(string[] args)
{
// Console sizing can cause exceptions if you are using a
// small monitor. Change as required.
Console.SetWindowSize(152, 58);
Console.BufferHeight = 1500;
string filePath = ConfigurationManager.AppSettings["MonitoredTextFilePath"];
Console.Title = string.Format("Live Logs {0}", filePath);
var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
// Move to the end of the stream so we do not read in existing
// log text, only watch for new text.
fileStream.Position = fileStream.Length;
StreamReader streamReader;
// Commented lines are for duplicating the log output as it's written to
// allow verification via a diff that the contents are the same and all
// is being output.
// var fsWrite = new FileStream(#"C:\DuplicateFile.txt", FileMode.Create);
// var sw = new StreamWriter(fsWrite);
int rowNum = 0;
while (true)
{
streamReader = new StreamReader(fileStream);
string line;
string rowStr;
while (streamReader.Peek() != -1)
{
rowNum++;
line = streamReader.ReadLine();
rowStr = rowNum.ToString();
string output = String.Format("{0} {1}:\t{2}", rowStr.PadLeft(6, '0'), DateTime.Now.ToLongTimeString(), line);
Console.WriteLine(output);
// sw.WriteLine(output);
}
// sw.Flush();
Thread.Sleep(500);
}
}
}
}
In addition to previous answers describing how to enable general logging, I had to modify one additional variable in my vanilla MySql 5.6 installation before any SQL was written to the log:
SET GLOBAL log_output = 'FILE';
The default setting was 'NONE'.
Gibbs MySQL Spyglass
AgilData launched recently the Gibbs MySQL Scalability Advisor (a free self-service tool) which allows users to capture a live stream of queries to be uploaded to Gibbs. Spyglass (which is Open Source) will watch interactions between your MySQL Servers and client applications. No reconfiguration or restart of the MySQL database server is needed (either client or app).
GitHub: AgilData/gibbs-mysql-spyglass
Learn more: Packet Capturing MySQL with Rust
Install command:
curl -s https://raw.githubusercontent.com/AgilData/gibbs-mysql-spyglass/master/install.sh | bash
If you want to have monitoring and statistics, than there is a good and open-source tool Percona Monitoring and Management
But it is a server based system, and it is not very trivial for launch.
It has also live demo system for test.