Percona is glad to announce the release candidate of Percona XtraBackup 8.0-3-rc1 on October 31 2018. You can download it from our download site and apt and yum repositories.
This is a Release Candidate quality release and
it is not intended for
production. If you want a high quality, Generally
Available release, use the current stable version (the
most recent …
Probably not well known but quite an important optimization was introduced in MySQL 5.6 – reduced overhead for “read only transactions”. While usually by a “transaction” we mean a query or a group of queries that change data, with transaction engines like InnoDB, every data read or write operation is a transaction.
Now, as a non-locking read operation obviously has less impact on the data, it does not need all the instrumenting overhead a write transaction has. The main thing that can be avoided, as described by documentation, is the transaction ID. So, since MySQL 5.6, a read only transaction does not have a transaction ID. Moreover, such a transaction is not visible in the SHOW ENGINE INNODB STATUS output, though I will not go deeper on what really that means under the hood in this article. The fact is that this optimization …
[Read more]The second alpha build of Percona XtraBackup 8.0.2 is now available in the Percona experimental software repositories.
Note that, due to the new MySQL redo log and data dictionary formats, the Percona XtraBackup 8.0.x versions will only be compatible with MySQL 8.0.x and Percona Server for MySQL 8.0.x. This release supports backing up Percona Server 8.0 Alpha.
For experimental migrations from earlier database server versions, you will need to backup and restore and using XtraBackup 2.4 and then use mysql_upgrade from MySQL 8.0.x
PXB 8.0.2 alpha is available for the following …
[Read more]MySQL Adventures: How max_prepared_stmt_count can bring down production
We recently moved an On-Prem environment to GCP for better scalability and availability. The customer’s main database is MySQL. Due to the nature of customer’s business, it’s a highly transactional workload (one of the hot startups in APAC). To deal with the scale and meet availability requirements, we have deployed MySQL behind ProxySQL — which takes care of routing some of the resource intensive SELECTs to chosen replicas. The setup consists of:
Post migration to GCP, everything was nice and calm for a couple of weeks, until MySQL decided to start misbehaving and leading to an outage. We were able to quickly resolve and bring the system back online and what follows are lessons from this experience.
The configuration of the …
[Read more]This post is a followup to my previous article https://www.percona.com/blog/2018/08/29/scaling-io-bound-workloads-mysql-cloud/
In this instance, I want to show the data in different dimensions, primarily to answer questions around how throughput scales with increasing IOPS.
A recap: for the test I use Amazon instances and Amazon gp2 and io1 volumes. In addition to the original post, I also tested two gpl2 volumes combined in software RAID0. I did this for the following reason: Amazon cap the single gp2 volume throughput to 160MB/sec, and as we will see from the charts, this limits InnoDB performance.
Also, a reminder from the previous post: we can increase gp2 IOPS by increasing volume size (to the top limit 10000 IOPS), and for io1 we can increase IOPS by paying per additional IOPS.
Scaling with InnoDB …
[Read more]Experimental Build of Percona XtraBackup 8.0 released
An experimental alpha version of Percona XtraBackup 8.0.1 is now available in the Percona experimental software repositories.
A few things to note about this release:
Is increasing GP2 volumes size or increasing IOPS for IO1 volumes a valid method for scaling IO-Bound workloads? In this post I’ll focus on one question: how much can we improve performance if we use faster cloud volumes? This post is a continuance of previous cloud research posts:
To recap, in Amazon EC2 we can use gp2 and io1 volumes. gp2 performance can be scaled with size, i.e for gp2 volume size of 500GB we get 1500 iops; size 1000GB – 3000 iops; and for 3334GB – 10000 iops (maximal …
[Read more]InnoDB depends on operating system threads to process the requests from user transactions, These transactions include requests to InnoDB before commit or rollback. The modern operating systems and servers with multi-core processors, where context switching is efficient, most workloads run well without any limit on the number of concurrent threads. InnoDB can efficiently control the number of concurrently executing operating system threads (and thus the number of requests that are processed at any one time) to minimize context switching between threads. if the number of threads concurrently executing is at a pre-defined limit, the new request sleeps for a short time before it tries again. The requests which cannot be rescheduled after the sleep is put in a first-in/first-out queue and eventually is processed. Threads waiting for locks are not counted in the number of concurrently executing threads.To limit the number of …
[Read more]As a spin-off from the previous post, https://mysqlmed.wordpress.com/2018/08/23/get-the-auditors-in/, I thought that it would be good to see how well the Audit plugin upgrades to MySQL 8. The big change in auditing is that the tables change from MyISAM to InnoDB, so keep your eyes open.
I’m using the previously used instance in version 5.7.18.
Preparation
Before we do anything, let’s make sure auditing will be in place when we restart the instance with 8.0.12:
Uncomment the plugin-load & audit-log params we had originally commented out. After all, this is something we should have done in the last post (apologies!):
vi my_audit.cnf: .. [mysqld] plugin-load =audit_log.so audit-log =FORCE_PLUS_PERMANENT ..
Restart the 5.7 instance so we upgrade from a rebooted / ‘as real as can be …
[Read more]Here I have been looking into using the MySQL Enterprise Edition Audit Log plugin for 5.7. We have many options to audit (filters, encryption, compression, Workbench, rotation & purging, viewing the log, etc.) and it’s quite clear cut on what we’re auditing and not when active.
If you’re looking to go deep into the Audit Plugin, as part of the Enterprise Edition, you’ll want to look at the following Support note:
Master Note for MySQL Enterprise Audit Log Plugin (Doc ID 2299419.1)
And if you’re looking for other Audit Plugin examples, I’d recommend Tony Darnell’s blog post:
…
[Read more]