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Displaying posts with tag: RocksDB (reset)
Open Core Summit and OSS glue code

I am optimistic about the Open Core Summit. It can be something that benefits users, startups, the source-available community and the OSS crowd. The summit has many of the important people from the open core community. It is an opportunity for them to collaborate -- form a foundation, reduce open core license proliferation, discuss the next license to be reviewed by OSI and most importantly -- fix the open core marketing approach.

I appreciate that startups put so much time and money into building interesting system software that is shared either as OSS or source-available. I haven't enjoyed much of the marketing about the challenges that cloud creates for VC-funded …

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Exposing MyRocks Internals Via System Variables: Part 7, Use Case Considerations

(In the previous post, Part 6, we covered Replication.)

In this final blog post, we conclude our series of exploring MyRocks by taking a look at use case considerations. After all, having knowledge of how an engine works is really only applicable if you feel like you’re in a good position to use it.

Advantages of MyRocks

Let’s start by talking about some of the advantages of MyRocks.

Compression

MyRocks will typically do a good job of reducing the physical footprint of your data. As I mentioned in my previous post in this series about compression, you have the ability to configure compression down to the individual compaction layers for each column family. You also get the advantage of the fact that data isn’t updated once it’s written to disk. Compaction, which was …

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Exposing MyRocks internals Via system variables: Part 6, Replication

(In the previous post, Part 5, we covered Data Reads.)

In this blog post, we continue our series of exploring MyRocks mechanics by looking at the configurable server variables and column family options. In our last post, I explained at a high level how reads occur in MyRocks, concluding the arc of covering how data moves into and out of MyRocks. In this post, we’re going to explore replication with MyRocks, more specifically read-free replication.

Some of you may already be familiar with the concepts of read-free replication as it was a key feature of the TokuDB engine, which leveraged fractal tree indexing. TokuDB was similar to MyRocks in the sense that it had a pseudo log-based storage …

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Exposing MyRocks internals via system variables: Part 5, Data Reads

(In the previous post, Part 4, we covered Compression and Bloom Filters)

In this blog post, we continue on our series of exploring MyRocks mechanics by looking at the configurable server variables and column family options. In our last post, I explained at a high level how compression and bloom filtering are applied to data files as they are initially flushed from immutable memtables and are subsequently passed through the compaction process. With that being covered, we should now have a clear understanding as to how data writing works in MyRocks and can start reviewing how data read requests are handled.

The Read Process

Let’s start off by talking about how read processes are handled at the file level. When a read request comes in, the first thing it needs to do is pull the …

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Hot Backup For MyRocks(Rocksdb) using Percona Xtrabackup

Xtrabackup now supports Hotbackup for Myrocks!! yes you heard me right, this is one of the most awaited features with xtrabackup. With the latest release of percona xtrabackup 8.0.6 this is enabled and is supported only for Percona Server version 8.0.15-6 or higher, you can see detailed released notes here.

Myrocks is getting much of the attention now because of its much improved write capabilities and compression. We have also planned to have detailed blog on Myrocks features and limitations.

We shall proceed to test the backup and restore of Myrocks

Environment:

OS : Debian GNU/Linux 9 …
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CRUM conjecture - read, write, space and cache amplification

The RUM Conjecture asserts that an index structure can't be optimal for all of read, write and space. I will ignore whether optimal is about performance or efficiency (faster is better vs efficient-er is better). I want to use CRUM in place of RUM where C stands for database cache.

The C in CRUM is the amount of memory per key-value pair (or row) the DBMS needs so that either a point query or the first row from a range query can be retrieved with at most X storage reads. The C can also be reported as the minimal database : memory ratio to achieve at most X storage reads per point query.

My points here are:

  • There are …
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Exposing MyRocks Internals Via System Variables: Part 3, Compaction

(In the previous post, Part 2, we covered Initial Data Flushing.)

In this blog post, we continue our series of exploring MyRocks mechanics by looking at the configurable server variables and column family options. In our last post, I explained at a high level how data moves from immutable memtables to disk. In this post, we’re going to talk about what happens to that data as it moves through the compaction process.

What is Compaction?

One of the philosophies of MyRocks is “write the data quickly and sort out data organization later”, which is pretty far removed from engines like InnoDB that take the approach of “continuously organize data on disk so it’s optimal as soon as possible”. MyRocks implements its philosophy in a way that is heavily reliant on a process …

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Exposing MyRocks Internals via system variables: Part 2, Initial Data Flushing

(In the previous post, Part 1, we covered Data Writing.)

In this blog post, we continue on our series of exploring MyRocks mechanics by looking at configurable server variables and column family options. In our last post, I explained at a high level how data first entered memory space and in this post, we’re going to pick up where we left off and talk about how the flush from immutable memtable to disk occurs. We’re also going to talk about how newly created secondary indexes on existing tables get written to disk.

We already know from our previous post in the series that a flush can be prompted by one of several events, the most common of which would be when an active memtable is filled to its maximum capacity and is rotated into immutable status.

When your immutable memtable(s) is ready …

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Exposing MyRocks internals via system variables: Part 1, Data Writing

Series Introduction

Back in 2016 I decided to write a blog series on InnoDB in hopes that it would help give a good description of the high level mechanics of the storage engine. The main motivating factor at that time was that I knew there was a lot of information out there about InnoDB, but a lot of it was ambiguous or even contradictory and I wanted to help make things a bit clearer if I could.

Now there’s a new storage engine that’s rising in popularity that I feel needs similar attention. Specifically MyRocks, the log-structured merge-driven RocksDB engine in MySQL. Given the amount of discussion in the community about MyRocks, I’m sure most of you already have some degree of familiarity, or at the very least have heard the name.

Now we’ve arrived at a point where this is no longer just a Facebook integration project and major players in the community like Maria and Percona have their own implemented …

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Less "mark" in MySQL benchmarking

My goal for the year is more time learning math and less time running MySQL benchmarks. I haven't done serious benchmarks for more than 12 months. It was a great experience but I want to learn new things. MySQL 8.0.14 has been released with fixes for a serious bug I found via the insert benchmark. I won't confirm whether it has been fixed. I hope someone else does.

My tests and methodology are described in posts for sysbench, linkbench and the insert benchmark.  I hope the upstream distros (MySQL, MariaDB, Percona) repeat my tests and methodology and I am happy to answer questions about that. I even have inscrutable shell scripts that …

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