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Troubleshooting and monitoring - AWS Elemental MediaTailor
MetricsLog eventsExample CloudWatch Insights queriesCalculating yield liftCommon issuesAPS error codes reference

Troubleshooting and monitoring

This page helps you monitor Yield Optimization performance, diagnose common issues, and validate that your configuration is working correctly.

Metrics

MediaTailor publishes the following CloudWatch metrics for Yield Optimization. All metrics are emitted with a configurationName dimension unless noted otherwise.

Bid request metrics

Metric Description
YieldOptimization.BidRequest Emitted as 1 when a bid request opportunity is identified.
YieldOptimization.BidResponse Emitted as 1 when a successful bid response is received.
YieldOptimization.BidDuration The break duration (seconds) requested in the bid, calculated from avail duration minus primary ad duration.
YieldOptimization.Latency Round-trip latency to APS in milliseconds.
YieldOptimization.NoBid Emitted as 1 when APS returns HTTP 204 (no matching demand). The request itself was valid.
YieldOptimization.BidRequestThrottled Emitted as 1 when APS returns HTTP 429 (throttled). APS is applying back-pressure. Back off before retrying.

Ad insertion metrics

Metric Description
YieldOptimization.AdsInserted Number of YO ads inserted into the avail.
YieldOptimization.AdsReturned Number of ads returned in the BidResponse (before filtering). Only emitted when greater than 0.
YieldOptimization.FilledDuration Duration (ms) filled by YO ads.
YieldOptimization.UnfilledDuration Duration (ms) sent to APS in the bid request (opportunity gap).
YieldOptimization.FillRate Per-avail fill rate: transcoded YO duration divided by the pre-YO unfilled duration. The numerator is transcoded and the denominator is VAST-based (neither subtracts bumper), so the value can exceed 1.0.

Revenue and pricing metrics

Metric Description
YieldOptimization.Revenue Total revenue for the customer, sourced from the price attribute of the oRTB bid response. Sum of price across inserted ads.
YieldOptimization.IndicativeBidRevenue Summed per-impression indicative value of all RETURNED bids (bid price per impression, not per insertion). Dual-emitted alongside Revenue during a deprecation window and will be removed once dashboards cut over. Use Revenue for new dashboards.
YieldOptimization.BidPriceAdsInserted The CPM price of each ad inserted by Yield Optimization. Dimensioned by the bid response cur (currency) attribute. Not emitted per-customer, so this is account-wide.
YieldOptimization.BidPriceAdsReturned The CPM price of each bid returned in the BidResponse (before filtering to insertions). Dimensioned by cur. Not emitted per-customer, so this is account-wide.

Error and skip metrics

Metric Description
YieldOptimization.Errors Emitted as 1 for connection errors, response processing errors, or unexpected exceptions. Also emitted as 0 on success (use Sum, not SampleCount).
YieldOptimization.Timeouts Emitted as 1 when the APS request times out. Also emitted as 0 on success (use Sum, not SampleCount).
YieldOptimization.BidRequestConfigurationError Emitted as 1 when the template or bid construction fails (missing fields, invalid JSON).
YieldOptimization.SkipMinUnfilledDurationNotExceeded Emitted as 1 when YO was skipped because unfilled duration was below the threshold.
YieldOptimization.SkipPersonalizationTimeoutExceeded Emitted as 1 when YO was skipped because insufficient personalization time remained.
Important

YieldOptimization.Errors and YieldOptimization.Timeouts are emitted as 0 on every successful request. Use Sum (not SampleCount) in CloudWatch to get the actual error or timeout count. NoBid and BidRequestThrottled are NOT counted in Errors. They are separate signals for legitimate no-demand and back-pressure conditions.

Log events

Yield Optimization generates events in the MidasMMSService/ads_interaction_log log group:

Event type Description
RAW_BID_REQUEST The complete OpenRTB bid request JSON sent to APS. Use this to verify template interpolation.
RAW_BID_RESPONSE The raw OpenRTB bid response from APS, including bid pricing and VAST XML.
FILLED_AVAIL The complete avail with all ads. YO ads have fillMode: "YIELD_OPTIMIZATION" and include bidId, bidPrice, currency, impressionId, and seatId.

Error events are emitted in MidasMMSService/application.log with loggers like YieldOptimizationSupport, OrtbBidRequestBuilder, HttpOrtbRequestSubmitter, and OrtbResponseProcessor.

Example CloudWatch Insights queries

Check for YO errors

fields @timestamp, message.sessionId, message.message, log.logger, log.level
| filter message.awsAccountId = 'YOUR_ACCOUNT_ID'
  and (log.level = 'ERROR' or log.level = 'WARN')
  and (log.logger like /YieldOptimization/
    or log.logger like /OrtbResponseProcessor/
    or log.logger like /HttpOrtbRequestSubmitter/
    or log.logger like /OrtbBidRequestBuilder/)
| sort @timestamp desc
| limit 100

Log group: MidasMMSService/application.log

Count bid requests vs responses

fields @timestamp, sessionId, eventType
| filter awsAccountId = 'YOUR_ACCOUNT_ID'
  and (eventType = 'RAW_BID_REQUEST' or eventType = 'RAW_BID_RESPONSE')
| stats count(*) by eventType

Log group: MidasMMSService/ads_interaction_log

Find YO ads in filled avails

Each FILLED_AVAIL event contains a creativeAds array. YO ads within that array carry fillMode: "YIELD_OPTIMIZATION" and additional bid metadata: bidId, impressionId, bidPrice, seatId, and currency. Use this to see which avails were filled by YO, how many YO ads were inserted per avail, and the revenue attribution per bid.

fields @timestamp, sessionId, avail.availId, avail.numAds, avail.fillRate, avail.filledDuration
| filter awsAccountId = 'YOUR_ACCOUNT_ID'
  and eventType = 'FILLED_AVAIL'
  and @message like /YIELD_OPTIMIZATION/
| sort @timestamp desc
| limit 50

To pull the individual YO ad entries (bid ids and prices) for a specific session:

fields @timestamp, sessionId, avail.availId, avail.creativeAds
| filter awsAccountId = 'YOUR_ACCOUNT_ID'
  and eventType = 'FILLED_AVAIL'
  and sessionId = 'YOUR_SESSION_ID'
| sort @timestamp desc
| limit 20

Filter the resulting creativeAds array client-side for entries where fillMode == "YIELD_OPTIMIZATION".

Log group: MidasMMSService/ads_interaction_log

Check for unresolved template variables

fields @timestamp, sessionId, @message
| filter awsAccountId = 'YOUR_ACCOUNT_ID'
  and eventType = 'RAW_BID_REQUEST'
  and @message like /\{[A-Z_]+\}/
| sort @timestamp desc
| limit 20

Log group: MidasMMSService/ads_interaction_log

Measure YO latency and success rate

fields @timestamp, @message
| filter customerId = 'YOUR_ACCOUNT_ID'
  and (@message like /YieldOptimization/ or @message like /ortb_/)
| limit 10000

Log group: MidasMMSService/service_log

Note

service_log uses customerId (not awsAccountId) for the account ID field.

Calculating yield lift

To measure the revenue impact of Yield Optimization, create a CloudWatch dashboard with:

  1. Incremental fill rate: Sum(YieldOptimization.AdsInserted) / Sum(YieldOptimization.BidRequest) shows what percentage of YO opportunities result in inserted ads. Alternatively, use Average(YieldOptimization.FillRate) for the per-avail native metric.

  2. Revenue per hour: Sum(YieldOptimization.Revenue) over time shows total per-customer revenue from YO. Sum(YieldOptimization.BidPriceAdsInserted) gives account-wide average CPM.

  3. Duration filled: Sum(YieldOptimization.FilledDuration) against Sum(YieldOptimization.BidDuration) shows how much of the requested duration was actually filled.

Common issues

Yield Optimization not triggering

Symptom Check Resolution
No YO metrics at all Is YO configured on the playback config? Enable YO in the console or API.
SkipMinUnfilledDurationNotExceeded emitting Primary ADS is filling most of the break Lower MinimumUnfilledDuration or accept that primary fill is sufficient.
SkipPersonalizationTimeoutExceeded emitting Primary ADS is too slow, leaving no time for YO Optimize primary ADS latency or check personalization timeout SDC configuration.

Bid requests failing

Symptom Check Resolution
BidRequestConfigurationError metric Template has missing or empty mandatory fields Check application.log for the specific error (for example, app.bundle is required). Fix the template or ensure player params are sent.
HTTP 204 from APS YieldOptimization.NoBid incrementing APS returned no-bid. Not an error. Inspect RAW_BID_REQUEST for placeholder values ({UPPER_CASE} patterns), verify bundle and storeurl are real, lower bidfloor.
HTTP 429 from APS YieldOptimization.BidRequestThrottled incrementing APS is throttling. Back off request rate. If persistent, contact APS support to raise TPS limits.
HTTP 400 from APS Invalid request JSON Check the APS error message in RAW_BID_RESPONSE. Verify JSON structure matches OpenRTB spec.
HTTP 500/503 from APS APS server error or overload Transient issue. Monitor YieldOptimization.Errors. If persistent, contact APS support.

Ads returned but not inserted

Symptom Check Resolution
AdsReturned > 0 but AdsInserted = 0 Ads filtered during insertion Check FILLED_AVAIL logs for skip reasons: duplicate creatives, leftover threshold exceeded, or ad variant not found (transcoding not complete).

APS error codes reference

Code Meaning Common causes
200 Success with bids Working correctly.
204 No bid The request is valid but no bids were available. This does not indicate an error in your template.
400 Bad request Invalid JSON, missing required fields per OpenRTB spec.
500 Server error APS internal issue, service throttled, timeout.
503 Service overloaded APS back-pressure. Do not retry aggressively.
429 Throttled APS has manually started to throttle requests. Contact APS support if persistent.