Search Results for: synchronous replication

Measuring Max Replication Throughput on Percona XtraDB Cluster with wsrep_desync

Checking throughput with async MySQL replication Replication throughput is the measure of just how fast the slaves can apply replication (at least by my definition).  In MySQL async replication this is important to know because the single-threaded apply nature of async replication can be a write performance bottleneck.  In a production system, we can tell […]

Multicast replication in Percona XtraDB Cluster (PXC) and Galera

Bandwidth multiplication and synchronous clusters I’ve seen a lot of people setting up clusters with 3-6+ nodes on 1 Gbps networks.  1 Gbps seems like a lot, doesn’t it?  Actually, maybe not as much as you think.  While the theoretical limit of 1Gbps is actually 120MBps, I start to get nervous around 100MBps. By default […]

Accessing Percona XtraDB Cluster nodes in parallel from PHP using MySQL asynchronous queries

This post is followup to Peter’s recent post, “Investigating MySQL Replication Latency in Percona XtraDB Cluster,” in which a question was raised as to whether we can measure latency to all nodes at the same time. It is an interesting question: If we have N nodes, can we send queries to nodes to be executed in […]

Investigating MySQL Replication Latency in Percona XtraDB Cluster

I was curious to check how Percona XtraDB Cluster behaves when it comes to MySQL replication latency — or better yet, call it data propagation latency. It was interesting to see whenever I can get stale data reads from other cluster nodes after write performed to some specific node. To test it I wrote quite a […]

Comparing Percona XtraDB Cluster with Semi-Sync replication Cross-WAN

I have a customer who is considering Percona XtraDB Cluster (PXC) in a two colo WAN environment.  They wanted me to do a test comparing PXC against semi-synchronous replication to see how they stack up against each other. Test Environment The test environment included AWS EC2 nodes in US-East and US-West (Oregon).  The ping RTT latency […]

Optimizing Percona XtraDB Cluster for write hotspots

Some applications have a heavy write workload on a few records – for instance when incrementing a global counter: this is called a write hotspot. Because you cannot update the same row simultaneously from multiple threads, this can lead to performance degradation. When using Percona XtraDB Cluster (PXC), some users try to solve this specific […]