Read and Write Latency

List

 The Read Latency and Write Latency options display:

  • Reads/Writes: the average number of local read or write requests processed per second, by each node in the cluster
  • 95th Percentile: the latest mean (Avg. Node Mean) and 95th percentile (Avg. Node 95th % Latency) latency metrics
  • Distribution: the percentile distribution of latency metrics

for each column family in the cluster.

The Avg. Node Mean column is the mean read or write latency for the column family, on each node in the cluster (over roughly the last five minutes), averaged across the cluster.

The Avg. Node 95th % Latency column is the read or write latency for which 95% of sampled values fall below, on each node in the cluster (over roughly the last five minutes), averaged across the cluster.

The 50th percentile, 75th percentile, 95th percentile and 99th percentile columns show the respective latency metrics below which 50%, 75%, 95% and 99% of latency metrics fall (over roughly the last five minutes), averaged across the cluster.

High latency values may indicate a cluster at the edge of its processing capacity, issues with the data model such as poor choice of partition key or high levels of tombstones or issues with the underlying infrastructure. If you require assistance diagnosing the source of latency issues then please contact support@instaclustr.com. 

Graph

The Read Latency and Write Latency options show:

  • Reads/Writes: the number of local read or write requests per second for the column family, per node, over the most recent period of time
  • 95th Percentile: the mean and 95th percentile latency metrics per node, over the last hour
  • Distribution: the 50th, 75th, 95th and 99th percentile latency metrics per node, over the last hour

 

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