Galera Cluster Enterprise Edition (EE) has had support for Non-Blocking Operations (NBO) schema upgradesever since the first release of Galera Cluster Enterprise Edition (EE). It is reasonably well documented, and we think more people will benefit from using it, of course. Schema changes tend to always remain a daunting task when you have large databases to manage.

To compare between Total Order Isolation (TOI), the default, with NBO that is available in Galera Cluster Enterprise Edition (EE), we create a test table:

CREATE TABLE large;
USE large;

CREATE TABLE test_table (
    id INT PRIMARY KEY AUTO_INCREMENT,
    data VARCHAR(255),
    num1 INT,
    num2 INT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

Then we …

Percona XtraDB Cluster 8.0.25 (PXC) has introduced a new option to perform online schema modifications: NBO (Non-Blocking Operation).

When using PXC, the cluster relies on the wsrep_OSU_method parameter to define the Online Schema Upgrade (OSU) method the node uses to replicate DDL statements. 

Until now, we normally have three options:

• Use Total Isolation Order (TOI, the default)
• Use Rolling Schema Upgrade (RSU)
• Use Percona’s online schema change tool (TOI + PTOSC)

Each method has some positive and negative aspects. TOI will lock the whole …