All,
Our product uses Mysql enterprise db. currently at 5.5.42 but planning to upgrade to 5.7.latest. What changes should I expect to see ?
I'm interested in :
1) Performance impacts
2) Broken behavior
3) Changed behavior
4) Improvements -- functional and performance-wise
Is it advised to 1st upgrade our product to use 5.6.x and then next to 5.7.x OR directly to 5.7.x and then test/QA from there ? Any inputs will be valuable.
Performance
Performance gains in 5.7 can be achieved only on high loaded systems. If you have less than 40-60 parallel executions, then expect small performance fall around 10%. This is very system- and load-dependent. Always test yourself!
Here is good MySQL 5.7 performance test done by Percona: https://www.percona.com/blog/2016/05/17/mysql-5-7-read-write-benchmarks/
Changed and broken behaviour, Improvements
There were a lot of changes in 5.7. Check this link for complete list: http://www.thecompletelistoffeatures.com/
I would mention the following changes, that one should think of during upgrade:
SQL_MODE was changed. It is good for new installations, but for old systems most probably you will have to set it back to the old value.
First GA release had password expiry, but after complaints it was disabled in 5.7.11. So nothing to worry about now.
SQL optimizer was changed a lot. Queries should run faster now, but I expect, that some could run slower. The most time should be spent on queries testing on the new version!
Here is good overview of all changes affecting upgrade to 5.7:
http://dev.mysql.com/doc/refman/5.7/en/upgrading-from-previous-series.html
Upgrade
There are two ways to upgrade: using mysql_upgrade and mysqldump.
With mysql_upgrade go with one version at a time. There is no need to test intermediary version. Test only final version.
With mysqldump go directly to 5.7. It is advisable to skip mysql database. Users can not be migrated with mysqldump, use grant statements.
For further information read this: http://dev.mysql.com/doc/refman/5.7/en/upgrading.html
There are tremendous amount of change between 5.5 and 5.7. It's simply not practical to enlist them all here. I'll try to highlight the most important ones. Obviously there are also a lot of new features introduced (GTID, semi-sync replication, JSON support, virtual columns etc.).
1) Performance
You should expect performance gains since 5.6 and 5.7 improved a lot in mutex handling therefore less contention is expected.
Also scalability improvements were done so you can scale your servers up further and performance/query capacity follows for longer than before.
There were a lot of change in the optimizer. So make sure to check your queries.
At the end of the day you should always check your own case with the your own application.
2+3) Changed and broken behaviour
Password expiry. In 5.7 passwords can have expire time. Just something to be aware of.
Password management commands have changed so make sure you check them before you get surprised by having your automation broken.
Since optimizer and the cost model changed a lot some queries might get executed differently.
Two parameters I would mention specifically that caused some headaches for us: Look into the optimizer_switch and decide what you turn on and off. range_index_dive_limit default value was raised from 10 to 200 by default in 5.7.4+. Since I see this parameter is rarely being set in any my.cnf this new default might affect you big time.
4) Improvements
A lot. As I wrote above there are plenty of new features and scalability, performance improvements that were meant to server you better.
5) Upgrade path
Yes, it's best to do one major upgrade at a time, test and when everything's working you can do the second major upgrade.
Compatibility - The issue that would be your greatest concern when upgrading. Because your codes/syntaxes are made with lower version, expect them to behave differently for some of them will be invalid or would not be recognized with the newer version (great impact will be occurred if you jump to a very far higher version).
Normally, you'll get improved performance, security, etc with newer versions but you need to bend your codes/syntaxes to cope with new functions and features.
Related
I've been testing the performance between 5.7 and 8.0.
We figured out that our application is around 30% slower with 8.0, so I tried to narrow down the issue.
I've started running simple sysbench tests and they showed the same perf hit.
Then I found this nice article.
I tried to replicate the setup (4 cores, NVMe backend, only VM on the host, etc) the best I can.
I used two separate VMs based on CentOS 7 with community editions.
However, after tests I got the same ~30% perf hit with the same scripts found in the blog post.
Then I tried to add the my.cnf options mentioned in the blog, nothing. Apart from these options, my.cnf was left as default (except innodb_buffer_pool, which was set to 8G from the start and binlogs were disabled on both).
As a last resort I just tried a simple sysbench run (removed all the extra options, ran it for 10 minutes), same thing.
I even tried to force M8 to use latin1 instead of utf8 (while creating the DB), which yielded these (best) results:
Results
Everything points to M8 having way less performance as M5.7, which contradicts ALL google listing.
Does anyone have any idea where the perf hit comes from?
Thanks in advance!
8.0 implements ROLLBACK for DDL statements such as CREATE/DROP/ALTER TABLE/DATABASE/COLUMN. This makes them slower.
For most applications, this is not a performance problem because DDL is only a rare event. Are you doing a lot of DDL statements?
From several9s, that shows tons of improvements that are present in MySQL 8.0. The benchmark results reveals that there has been an impressive improvement, not only on managing read workloads, but also on a high read/write workload comparing to MySQL 5.7.
Here are the benchmark results:
Overall, MySQL 8.0 has dominated MySQL 5.7 efficiently. Especially if you have a high number of threads, I believe you must use MySQL 8.0.
Mysql 8.0 vs Mysql 5.7 performance comparison
At present in my production , I'm using mysql 5.7 version.
I want to upgrade my database to mysql8 .
I need a performance comparison among these three.
After searching Mysql5.7 vs Mysql 8.
My findings are the followings :
Creating Role
Invisible index
...etc
Insert operations are slower because of binary logging
and we can disable it.
Use slightly more RAM than 5.7 version
But what i really need is a comparison based on performance .
Connection handling, thread, pooling , max user , max connection, processing,CPU usage,memory something like this.
Thanks in advance.
To be honest, here's no clear cut answer for you. 90% of the performance is defined by database design and implementation, not the actual version of MySQL used.
The ability to handle load and stress is mostly the same between versions. Some things under the same configurations may be performing better on the newer version, some other things on older.
Most metric in your list (handling, thread, pooling, max user, max connection, processing, CPU usage, memory, etc) are usually fine tuneable on both my.cnf and OS sysctl level. Even kernel tweaks can have an effect.
So, in general, 90% of people can't see the performance difference. On the other hand, 90% also fail at doing proper performance tests too.
I need to upgrade our MySQL 5.0.27 database to 5.5. I understand there are some significant performance increases even between 5.0.27 and 5.1.
Before I complete the upgrade I would like to have a base for performance testing before and after the upgrade.
I have several tables with 500k+ rows and one with 5.8m+ rows.
Is there a query or method I can use to get a good reliable performance metric from my own data before and after the upgrade?
You should run benchmark tests with the queries that your system currently runs, there is no point in profiling queries that your database won't likely run when under a real world load as it won't let you see how your actual system will run, which ultimately is the only thing that matters.
I'm going to be bold and assume that you're only interested in the performance gains for your application. So I would suggest that you first copy the current environment and settings (so that's MySQL 5.0.27 et all) on a test server and simulate standard load and user interaction. Then upgrade to MySQL 5.1 or 5.5 on the test server and perform the same simulation, that way you get the real numbers you are interested in and you can practice on rolling out all these updates.
You can use something as http://loadimpact.com/ for a reliable benchmark of your website. But always do multiple runs and take the average, min, and max to compare it.
Currently have approximately 2000 simultaneouse connections. We average approximately 425 reads and writes per second. We have a read to write ration of 3:1. All of our tables are myisam. Can we expect better or worse performance when we go from mysql 4.1.22 to 5.0?
There's no way for anyone here to tell you without the schema, queries and test data.
Why not setup a dev environment on 5.0 and testing it out?
The main concern should be that the 5.0 Information Schemas, are a HUGE vulnerability and can be used to very easily gain access to the SQL server from remote locations simply by printing off the schema using injection will let an unwanted viewer, view all of the tables and capitalize off the knowledge to get passwords using the same schema for its columns.
The MySQL source tree includes a set of benchmark tests written as Perl scripts. See The MySQL Benchmark Suite for some information. You can download the source distribution for MySQL 5.0.91 at the archives.
Source distribution of MySQL 4.1 doesn't seem to be easily available anymore. You might have to check it old sources from LaunchPad unless you can find a copy of an old source distribution elsewhere on the internet.
However, the comparison that these benchmarks show is only of general interest. It may be irrelevant to how your application performs. For instance, your usage of the database may not take advantage of some performance improvements in MySQL 5.0, but it may run into some regressions in MySQL 5.0 that were necessary.
The only way to get an answer that is relevant to your application is to try the new software with a test instance of your application, using a sample of data that is a realistic model of the type and volume of data your application typically deals with. As #BenS says, no one on a site like StackOverflow can give an answer specific to your application.
You say in a comment that you're very concerned about performance, but if you don't have an instance of your application and database that you can run tests on, you aren't doing the work necessary to satisfy this concern.
I would strongly suggest moving straight to 5.1.45 with Innodb Support. Percona provides an excellent version with XtraDB that provides a number of performance related improvements. Moving off of your MyISAM tables and onto Innodb will provide a huge performance increase in almost all cases. If you are going to burn the QA/Testing time to move, do a full move now, not a half-way step.
We had an applicationg running using MySql. We found MySql was not suitable for our app after we found that it didnt support some of the GIS capability that PostGIS has (note: mysql only supports minimum-bounding rectangle GIS search).
So we changed our DB to PostgreSQL. We then found out that Postgresql 8.2 running on Windows is so much slower compared to Mysql 5.1. By slower, I mean at roughly 4-5 times slower.
Why is this? Is there something in the configuration that we need to change?
I found some comments from other websites such as this:
UPDATE: We found that the cause of the slowness is due to the BLOB that we are inserting into the DB. We need to be able to insert BLOB at a sustained rate of 10-15 MB/s. We are using libpq's lo_read and lo_write for each BLOB we are inserting/reading. Is that the best way? Has anyone used Pgsql for inserting large BLOB at a high rate before?
EDIT: I heard that PgSql just recently got ported to Windows. Could this be one of the reasons?
There are cases where PostgreSQL on Windows pays an additional overhead compared to other solutions, due to tradeoffs made when we ported it.
For example, PostgreSQL uses a process per connection, MySQL uses a thread. On Unix, this is usually not a noticeable performance difference, but on Windows creating new processes is very expensive (due to the lack of the fork() system call). For this reason, using persistent connections or a connection pooler is much more important on Windows when using PostgreSQL.
Another issue I've seen is that early PostgreSQL on Windows will by default make sure that it's writes are going through the write cache - even if it's battery backed. AFAIK, MySQL does not do this, and it will greatly affect write performance. Now, this is actually required if you have a non-safe hardware, such as a cheap drive. But if you have a battery-backed write cache, you want to change this to regular fsync. Modern versions of PostgreSQL (certainly 8.3) will default to open_datasync instead, which should remove this difference.
You also mention nothing about how you have tuned the configuration of the database. By default, the configuration file shipped with PostgreSQL is very conservative. If you haven't changed anything there, you definitely need to take a look at it. There is some tuning advice available on the PostgreSQL wiki.
To give any more details, you will have to provide a lot more details about exactly what runs slow, and how you have tuned your database. I'd suggest an email to the pgsql-general mailinglist.
While the Windows port of PostgreSQL is relatively recent, my understanding is that it performs about as well as the other versions. But it's definitely a port; almost all developers work primarily or exclusively on Unix/Linux/BSD.
You really shouldn't be running 8.2 on Windows. In my opinion, 8.3 was the first Windows release that was truly production-ready; 8.4 is better yet. 8.2 is rather out of date anyway, and you'll reap several benefits if you can manage to upgrade.
Another thing to consider is tuning. PostgreSQL requires more tuning than MySQL to achieve optimal performance. You may want to consider posting to one of the mailing lists for help with more than basic tweaking.
PostgreSQL is already slower than MySQL up to a certain point (it is actually faster when you have a ridiculously large database). Just FYI, this isn't causing your problem but keep that in mind.