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Your Amazon Aurora MySQL cluster looks healthy. Reads and writes succeed and every metric is green. Then a routine CREATE INDEX fails with error 63955, and from then on no index that includes a virtual column can be created on the cluster until you rebuild its databases.

Error Code: 63955. 
Index cannot be created because virtual index ID limit (4294967295) was reached.

• What it means: the cluster has used up the internal IDs Aurora MySQL uses when it evaluates indexes that contain a virtual column. This error does not affect existing data or ordinary indexes, but new indexes on VIRTUAL generated columns, functional indexes, and multi-valued indexes fail.
• What helps short term: converting the generated column in the failing index from VIRTUAL to STORED, so that the index no longer contains a …

When an Amazon Aurora MySQL-Compatible Edition instance runs critically low on memory, the operating system terminates the mysql process. This drops every connection, rolls back in-flight transactions, and triggers a cluster restart. The instinctive fixes (move to a larger instance, or lower max_connections) treat the symptom, not the underlying memory pressure your workload generates.

Aurora has long included out-of-memory (OOM) avoidance that watches system memory and takes recovery actions before the OS steps in. On Aurora MySQL version 3, use the aurora_oom_response parameter to configure these actions; Aurora provides sensible defaults that you can customize. Aurora MySQL version 8.4 adds a new instance-level …

When an Amazon Aurora MySQL-Compatible Edition or Amazon Relational Database Service (Amazon RDS) for MySQL database slows down, it can be hard to tell why. CPU graphs and slow-query logs rarely tell the whole story. The more direct answer usually lies in wait events. A wait event tells you what your sessions are waiting for: reading from storage, redo log flushes, acquiring an internal lock, or waiting for CPU time. Amazon CloudWatch Database Insights surfaces this data as DB load, so you can quickly see whether a database is constrained and, if so, on what.

Earlier MySQL wait-event guidance relied on the Performance Insights dashboard. Our 2018 post …

When MySQL commits a large transaction carrying gigabytes of changes, writing it to the binary log (binlog) can freeze every other commit on the server for minutes. This includes transactions that touch unrelated data. This bottleneck is detrimental to applications that depend on low commit latency. On October 29, 2026, AWS shipped an optimization into community MySQL that removes this bottleneck. We call it Binary Log Optimization for Large Transactions (BOLT). It has been available in Amazon Aurora MySQL since v1.22.0 and in all currently supported major versions (Aurora MySQL 2.x, 3.x, and 8.4.x), where it’s always on for every customer. BOLT is planned to be released as part of a future MySQL innovation release.

BOLT provides …