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Displaying posts with tag: BUG Reports (reset)
The weird messages Anthology of MySQL – Episode 1

Hi dear community.
Today I want to share with you some funny and weird error messages which can be extremely annoying

So let’s begin:

CREATE temporary TABLE `sbtest1_temp` (
  `k` int(11) NOT NULL DEFAULT '0',
  `c` char(120) NOT NULL DEFAULT '',
  `pad` char(60) NOT NULL DEFAULT '',
  `json_test_v` json GENERATED ALWAYS AS (json_array(`k`,`c`,`pad`)) VIRTUAL,
  `json_test_s` json GENERATED ALWAYS AS (json_array(`k`,`c`,`pad`)) STORED,
  `json_test_index` varchar(255) GENERATED ALWAYS AS (json_array(`k`,`c`,`pad`)) STORED,
  PRIMARY KEY (`id`),
  KEY `k_1` (`k`),
  KEY `json_test_index` (`json_test_index`)

ERROR 1478 (HY000): InnoDB: Unsupported encryption option for temporary tables.

Okay, let’s disable it:

CREATE temporary TABLE `sbtest1_temp` (
  `id` int(11) NOT NULL AUTO_INCREMENT, …
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Doc BUGs – an easy way to contribute Open Source project(part-1)

In this topic I would like to make some notes about questions, how we can contribute or help on Open Source project.
The first thing is, to learn the product itself, how to install, how to remove, how to use etc.
Of course, the first place for this information is an official documentation.
How you can use the DOC? I am taking following approach:
* Read the doc to learn the needed thing.
* Test the info provided in the DOC –
if the info is valid(i.e you have different results)
if it is not valid:
Report a bug – then continue reading.

The issue can be in DOC itself or in the product.
Did you find small typo in DOC? Did you think some info about topic is wrong? Or maybe you found wrong code samples?
Report it immediately and you will be the part of community.

Let’s take some DOC bug reports and examine them to get the idea.
The first is -> …

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MySQL blank users preventing slave I/O connection?

Recently I have encountered a weird simple issue with starting Slave server.

So created user as tried to run change master:

2017-10-30 14:03:59 DEBUG    Running -> /home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/bin/mysql -A -uroot -S/home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/socket.sock --force test -e 
'select @@port'
2017-10-30 14:03:59 DEBUG    Running -> /home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/bin/mysql -A -uroot -S/home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/socket.sock --force test -e 
"CREATE USER 'repl'@'%' IDENTIFIED BY 'Baku12345'"
2017-10-30 14:03:59 DEBUG    Running -> /home/shahriyar.rzaev/XB_TEST/server_dir/PS231017-percona-server-5.6.37-82.2-linux-x86_64-debug/bin/mysql -A -uroot …
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Using MySQL Connector/Python X (mysqlx module) MyRocks episode

This post is about, how I have tried to make simple Python script using mysqlx module work with MyRocks.
This is also related to pytest, as I have implemented simple pytest tests to call them from bash file.

So let’s discuss problem description:
The base problem is, by default when you create collection using Python X Plugin, the collection will have, 1 json type column called `doc` and 1 generated column from this `doc` column called `_id`.
So basically, you can not alter table engine to MyRocks because it will give an error something like:

ERROR 3106 (HY000): 'Specified storage engine' is not supported for generated columns.

The result:

Well, it can be solved by dropping generated `_id` column. Here we are encountering another issue that, if you have table with json data, please do NOT alter it to MyRocks, otherwise, you will get some weird results as described here:

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Using MySQL Connector/Python X (mysqlx module)

This post is about simple usage of mysqlx module i.e X Plugin with latest Connector/Python DMR.
The version of Python Connector is 8.0.4.


sudo yum install mysql-connector-python-8.0.4-0.1.dmr.el7.x86_64.rpm

Sample Python code:

# Connecting to MySQL and working with a Session
import mysqlx

# Connect to a dedicated MySQL server
session = mysqlx.get_session({
    'host': 'localhost',
    'port': 33060,
    'user': 'bakux',
    'password': 'Baku12345',
    'ssl-mode': mysqlx.SSLMode.DISABLED

schema = session.get_schema('generated_columns_test')

# Create 'my_collection' in schema

# Get 'my_collection' from schema
collection = schema.get_collection('my_collection')

assert(True == collection.exists_in_database())

# You can also add multiple documents at once …
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Testing MySQL 8.0 – let me create a ton of undo files

This is the late blog post about 2 recent bug reports

The basic idea came after reading ->

So the result of test ->
After each restart of MySQL the new undo log files are going to be created + keeping old files.

shahriyar.rzaev@qaserver-06:~/sandboxes/msb_8_0_1/data$ du -hs
# The count of undo files
shahriyar.rzaev@qaserver-06:~/sandboxes/msb_8_0_1/data$ ls | grep undo | wc -l

After new restart:

# New count
shahriyar.rzaev@qaserver-06:~/sandboxes/msb_8_0_1/data$ ls | grep undo | wc -l

So how to …

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My first patch for MySQL world; fixing BUG #76852

Hi dear MySQL Community.
I have reported a bunch of bugs and wrote some articles, but today is a special for me
Because today I send my first PR for MySQL source code.

So I have logged a bug -> #76852 and now fixed it after year.
Okey, I know I am lazy.

Let’s reproduce the bug.
Simulating full disk condition is easy as:

mkdir /filesystems
dd if=/dev/zero of=/filesystems/tmp_fs bs=1024 count=0 seek=$[1024*10]
mkfs.ext4 /filesystems/tmp_fs
mkdir small_mounted_dir
mount -o loop /filesystems/tmp_fs /home/sh/small_mounted_dir/

Then obtain MySQL source and compile it with DEBUG. If you don’t know how to do it just refer to -> installing-mysql-from-source-cmake-issues

From now you can use MySQL Sandbox to …

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Playing with MySQL Source code; Adding “STOP ALL SLAVES” command

This blog post is a result of reading book.
To be clear -> “Expert MySQL” by Charles Bell ->
This book explain internals of MySQL based on 5.6.x version. So relatively new and really good resource to use.

So the task is:
Chapter 8, “Extending MySQL High Availability” -> page 310, “Extending Replication”.
Where we should add new command -> “SQLCOM_STOP_SLAVES” executed on master and causing to STOP IO_THREAD on all slaves.
The basic idea is to run “STOP ALL SLAVES” on master, which in turn will appear on binary log and then it will applied on slaves.

MySQL version is 5.6.32.

So, as book advice go to sql/lex.h. “We are adding the new symbol for the command. This file contains the symbol array stored in …

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MySQL Shell, opening session in a wrong way

This topic is about general usage for MySQL Shell and X-Plugin.
The most important thing, i think we should keep in mind that, the X-Plugin will listen not MySQL’s port, but it’s own 33060 port as shown from log:

2016-07-15T07:21:09.454761Z 200 [Note] Plugin mysqlx reported: 'X plugin tcp connection enable at port 33060.'
2016-07-15T07:21:09.454959Z 200 [Note] Plugin mysqlx reported: 'Scheduler "work" started.'
2016-07-15T07:21:09.454976Z 200 [Note] Plugin mysqlx reported: 'X plugin initialization successes'
2016-07-15T07:21:09.484303Z 201 [Note] Plugin mysqlx reported: 'Using existing mysqlxsys@localhost account for authentication. Incomplete grants will be fixed'
2016-07-15T07:21:09.501627Z 0 [Note] Plugin mysqlx reported: 'Using OpenSSL for TCP connections'
2016-07-15T07:21:09.501752Z 0 [Note] Plugin mysqlx reported: 'Server starts handling incoming connections'

That’s …

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How fall in love with Failing assertion: !m_fatal?

The story about real love.
Once upon a time there was a bug about resizing innodb buffer pool size online ->
#77564 which was fixed on version MySQL 5.7.9.
But you can not stop the real love. Suddenly she came up and truely surprised me,because I was recently freed from depression. And now the same thing is happening again. With MySQL 5.7.12 if you try to resize:

mysql> set global innodb_buffer_pool_size = 107374182400;
Query OK, 0 rows affected (0.01 sec)

2016-05-31 11:50:18 0x7f7926ba1740 InnoDB: Assertion failure in thread 140158317500224 in file line 935
InnoDB: Failing assertion: !m_fatal

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