The latest from the MySQL community

The Model Context Protocol (MCP) has become a standard way for AI agents to discover the tools an application, database, or service offers. Claude Code, Codex, Cursor, Antigravity, et al. can connect to an MCP server, ask it what tools are available, and call these tools instead of figuring out what they can or can't do on the fly or piecing together API calls. Setting up an MCP server for a database usually means running a separate process that holds a database credential and turns tool calls into queries. Then you have another process to deploy, another place a credential lives, and a set of guardrails that sit outside the database.

The vsql-mcp extension from VillageSQL takes a different approach. It puts the MCP server inside the database. Install it, set a handful of global variables, and your MySQL server itself serves MCP over Streamable HTTP from a background …

Before MySQL 8.0, DDL was not crash-safe. There were three main problems:

1. The metadata in the server layer and the metadata/data in InnoDB could become inconsistent.

   The server-layer metadata was stored in files — for example, table definitions were kept in .frm files — while InnoDB kept its own copy of the metadata in its tables. A crash could leave the server-layer metadata inconsistent with InnoDB’s metadata or even with the table data. For example, the server layer still had the table’s .frm file and believed the table existed, but InnoDB’s .ibd data file was gone, so InnoDB believed the table did not exist.

2. InnoDB’s metadata and data could become inconsistent.

3. The binlog and the data could become inconsistent.

   For example, after a crash and …

Welcome back. This issue covers five weeks rather than the usual one — the gap since the August issue took in Percona Live Amsterdam, the launch of the OurSQL Foundation, and the run-up to the MySQL Galera Cluster end of life on 30 September.

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MySQL News

Note: Aggregated MySQL news can be found at Planet for MySQL Community and Planet MySQL (Oracle curated)

DISTANCE() and VECTOR_DISTANCE(): Vector Similarity in Percona Server for MySQL …

“Would making this capability available help a meaningful part of the MySQL community build better applications or run better systems?”

Q1. MySQL has recently made available several features from the enterprise tier to the MySQL Community Edition. What is driving this direction?

The simple answer is that Community Edition needs to stay strong for the people who build, run, and depend on MySQL every day. That includes developers, DBAs, startups, large enterprises, and software vendors.

When we bring broadly useful capabilities into Community Edition, particularly in areas like observability, high availability, performance, and developer experience, the whole MySQL ecosystem benefits. Users get a better platform, and we get better feedback from real workloads at scale.

Recent examples include replication observability and Group Replication capabilities, …

Starting with Percona XtraDB Cluster (PXC) 8.0, replication traffic encryption is enabled by default. That said, it’s common to find clusters running without TLS that suddenly need it: a new compliance requirement, an audit finding, a network segment that is no longer considered trusted.

PXC has a variable for exactly that case, pxc-encrypt-cluster-traffic, which handles SSL encryption for inter-node traffic, including State Snapshot Transfer (SST), Incremental State Transfer (IST), and the group communication the nodes use for replication.

The variable is not dynamic, and turning it on normally costs a full cluster restart since the node that encrypts traffic listens on ssl:// while its peers are still on tcp://. If a node joins the cluster with TLS enabled while remaining nodes don’t, the restarting node fails to reach out to the other peers with the following error:

2026-09-02T02:16:02.359992Z 0 [Note] [MY-000000] …

There are a few cryptography tasks that are common to many backends. For example, you should store passwords such that a database leak doesn't expose them, you should sign payloads so the receiving side can verify them, you should keep a column's data unreadable outside the database, and you should mint tokens an attacker cannot guess. MySQL's built-in functions cover part of that ground but fall short for many users. The SHA2() function will hash a password, but nothing salts it for you, so two people who pick the same password end up with the same stored value. MySQL does not have a built-in HMAC function. An HMAC is the keyed hash a receiver uses to tell a real message from a forged one.

When a database doesn't solve a problem natively, the work invariably moves up into application code, where every service reimplements it just a little bit differently. This adds ongoing maintenance complexity.

The …

When setting up a new database for an application, high availability (HA) is one of the main priorities. Let’s assume for this example that you chose to use a Percona XtraDB (PXC) cluster to host your database. But how does the application know which PXC node is healthy and can receive application traffic? Introducing a cluster of ProxySQLs can solve this problem, as ProxySQL will healthcheck the database nodes and route the application traffic to the healthy nodes. However, now the HA problem comes up again: how does the application know which ProxySQL host is healthy?

Putting “one more component” in front of your servers to make them highly available just shifts the problem up by one layer. From making the database HA, to making ProxySQL HA, to needing to make HAProxy HA and so on…

At some point, you may land on the common HA strategy, keepalived, but BGP ECMP is a powerful alternative worth considering.

What …

The alert fires at 06:37 and by the time anyone opens a laptop the database is back. The application log holds a wall of Lost connection to MySQL server during query, uptime says 41 days, and the error log records a clean shutdown: no crash, no signal, no out-of-memory kill. The next morning it happens at 06:12, and the morning after that not at all.

On a default Ubuntu or Debian server, unattended-upgrades installs security updates on a daily systemd timer, and when one touches MySQL, dpkg stops mysqld, upgrades the data directory to match the new binary, and starts it again while the machine stays up. Nothing rebooted. The database was replaced underneath a host that never stopped running.

That is deliberate, and the part nobody signed up for is that “a service” includes the database. We put a client in front of MySQL on an Amazon Elastic …

In this guide, we explain 150+ SQL commands in simple words, covering everything from basic queries to advanced functions for 2026. We cover almost every SQL command that exists in one single place, so you never have to go search for anything anywhere else. If you master these 150 commands, you will become an SQL […]

Oracle plans to move MySQL security updates toward a monthly cadence, supplementing the current quarterly Critical Patch Update (CPU) schedule. These monthly Critical Security Patch Update (CSPU) releases will be issued only when needed to address critical security or stability issues; they are not a fixed monthly release commitment. These CSPU releases will focus on […]