Viewing DAX Metrics and Dimensions - Amazon DynamoDB

Viewing DAX Metrics and Dimensions

When you interact with Amazon DynamoDB, it sends metrics and dimensions to Amazon CloudWatch. You can use the following procedures to view the metrics for DynamoDB Accelerator (DAX).

To view metrics (console)

Metrics are grouped first by the service namespace, and then by the various dimension combinations within each namespace.

  1. Open the CloudWatch console at https://console.aws.amazon.com/cloudwatch/.

  2. In the navigation pane, choose Metrics.

  3. Select the DAX namespace.

To view metrics (AWS CLI)

  • At a command prompt, use the following command.

    aws cloudwatch list-metrics --namespace "AWS/DAX"

DAX Metrics and Dimensions

The following sections contain the metrics and dimensions that DAX sends to CloudWatch.

DAX Metrics

The following metrics are available from DAX. DAX sends metrics to CloudWatch only when they have a non-zero value.

Note

CloudWatch aggregates the following DAX metrics at one-minute intervals:

  • CPUUtilization

  • CacheMemoryUtilization

  • NetworkBytesIn

  • NetworkBytesOut

  • NetworkPacketsIn

  • NetworkPacketsOut

  • GetItemRequestCount

  • BatchGetItemRequestCount

  • BatchWriteItemRequestCount

  • DeleteItemRequestCount

  • PutItemRequestCount

  • UpdateItemRequestCount

  • TransactWriteItemsCount

  • TransactGetItemsCount

  • ItemCacheHits

  • ItemCacheMisses

  • QueryCacheHits

  • QueryCacheMisses

  • ScanCacheHits

  • ScanCacheMisses

  • TotalRequestCount

  • ErrorRequestCount

  • FaultRequestCount

  • FailedRequestCount

  • QueryRequestCount

  • ScanRequestCount

  • ClientConnections

  • EstimatedDbSize

  • EvictedSize

  • CPUCreditUsage

  • CPUCreditBalance

  • CPUSurplusCreditBalance

  • CPUSurplusCreditsCharged

Not all statistics, such as Average or Sum, are applicable for every metric. However, all of these values are available through the DAX console, or by using the CloudWatch console, AWS CLI, or AWS SDKs for all metrics. In the following table, each metric has a list of valid statistics that are applicable to that metric.

Metric Description
CPUUtilization

The percentage of CPU utilization of the node or cluster.

Units: Percent

Valid Statistics:

  • Minimum

  • Maximum

  • Average

CacheMemoryUtilization

The percentage of available cache memory that is in use by the item cache and query cache on the node or cluster. Cached data starts to be evicted prior to memory utilization reaching 100% (see EvictedSize metric). If CacheMemoryUtilization reaches 100% on any node, write requests will be throttled and you should consider switching to a cluster with a larger node type.

Units: Percent

Valid Statistics:

  • Minimum

  • Maximum

  • Average

NetworkBytesIn

The number of bytes received on all network interfaces by the node or cluster.

Units: Bytes

Valid Statistics:

  • Minimum

  • Maximum

  • Average

NetworkBytesOut

The number of bytes sent out on all network interfaces by the node or cluster. This metric identifies the volume of outgoing traffic in terms of the number of bytes on a single node or cluster.

Units: Bytes

Valid Statistics:

  • Minimum

  • Maximum

  • Average

NetworkPacketsIn

The number of packets received on all network interfaces by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

NetworkPacketsOut

The number of packets sent out on all network interfaces by the node or cluster. This metric identifies the volume of outgoing traffic in terms of the number of packets on a single node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

GetItemRequestCount

The number of GetItem requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

BatchGetItemRequestCount

The number of BatchGetItem requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

BatchWriteItemRequestCount

The number of BatchWriteItem requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

DeleteItemRequestCount

The number of DeleteItem requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

PutItemRequestCount

The number of PutItem requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

UpdateItemRequestCount

The number of UpdateItem requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

TransactWriteItemsCount

The number of TransactWriteItems requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

TransactGetItemsCount

The number of TransactGetItems requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

ItemCacheHits

The number of times an item was returned from the cache by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

ItemCacheMisses

The number of times an item was not in the node or cluster cache, and had to be retrieved from DynamoDB.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

QueryCacheHits

The number of times a query result was returned from the node or cluster cache.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

QueryCacheMisses

The number of times a query result was not in the node or cluster cache, and had to be retrieved from DynamoDB.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

ScanCacheHits

The number of times a scan result was returned from the node or cluster cache.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

ScanCacheMisses

The number of times a scan result was not in the node or cluster cache, and had to be retrieved from DynamoDB.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

TotalRequestCount

Total number of requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

ErrorRequestCount

Total number of requests that resulted in a user error reported by the node or cluster. Requests that were throttled by the node or cluster are included.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

ThrottledRequestCount

Total number of requests throttled by the node or cluster. Requests that were throttled by DynamoDB are not included, and can be monitored using DynamoDB Metrics.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

FaultRequestCount

Total number of requests that resulted in an internal error reported by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

FailedRequestCount

Total number of requests that resulted in an error reported by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

QueryRequestCount

The number of query requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

ScanRequestCount

The number of scan requests handled by the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

ClientConnections

The number of simultaneous connections made by clients to the node or cluster.

Units: Count

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

EstimatedDbSize

An approximation of the amount of data cached in the item cache and the query cache by the node or cluster.

Units: Bytes

Valid Statistics:

  • Minimum

  • Maximum

  • Average

EvictedSize

The amount of data that was evicted by the node or cluster to make room for newly requested data. If the miss rate goes up, and you see this metric also growing, it probably means that your working set has increased. You should consider switching to a cluster with a larger node type.

Units: Bytes

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • Sum

CPUCreditUsage

The number of CPU credits spent by the node for CPU utilization. One CPU credit equals one vCPU running at 100% utilization for one minute or an equivalent combination of vCPUs, utilization, and time (for example, one vCPU running at 50% utilization for two minutes or two vCPUs running at 25% utilization for two minutes).

CPU credit metrics are available at a five-minute frequency only. If you specify a period greater than five minutes, use the Sum statistic instead of the Average.

Units: Credits (vCPU-minutes)

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

CPUCreditBalance

The number of earned CPU credits that a node has accrued since it was launched or started.

Credits are accrued in the credit balance after they are earned, and removed from the credit balance when they are spent. The credit balance has a maximum limit, determined by the DAX node size. After the limit is reached, any new credits that are earned are discarded.

The credits in the CPUCreditBalance are available for the node to spend to burst beyond its baseline CPU utilization.

Units: Credits (vCPU-minutes)

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

CPUSurplusCreditBalance

The number of surplus credits that have been spent by a DAX node when its CPUCreditBalance value is zero.

The CPUSurplusCreditBalance value is paid down by earned CPU credits. If the number of surplus credits exceeds the maximum number of credits that the node can earn in a 24-hour period, the spent surplus credits above the maximum incur an additional charge.

Units: Credits (vCPU-minutes)

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

CPUSurplusCreditsCharged

The number of spent surplus credits that are not paid down by earned CPU credits, and which thus incur an additional charge.

Spent surplus credits are charged when the spent surplus credits exceed the maximum number of credits that the node can earn in a 24-hour period. Spent surplus credits above the maximum are charged at the end of the hour or when the node is terminated.

Units: Credits (vCPU-minutes)

Valid Statistics:

  • Minimum

  • Maximum

  • Average

  • SampleCount

  • Sum

Note

The CPUCreditUsage, CPUCreditBalance, CPUSurplusCreditBalance, and CPUSurplusCreditsCharged metrics are available only for T3 nodes.

Dimensions for DAX Metrics

The metrics for DAX are qualified by the values for the account, cluster ID, or cluster ID and node ID combination. You can use the CloudWatch console to retrieve DAX data along any of the dimensions in the following table.

Dimension

CloudWatch Metric Namespace

Description

Account DAX Metrics

Provides aggregated statistics across all nodes in an account.

ClusterId Cluster Metrics

Limits the data to a cluster.

ClusterId, NodeId ClusterId, NodeId

Limits the data to a node within a cluster.