Add dynamic_service DBM propagation mode

[amarziali]

Description

Introduces a new DBM propagation mode value, dynamic_service, as a convenience alias for the combination of DD_DBM_PROPAGATION_MODE=service and DD_DBM_INJECT_SQL_BASEHASH=true. With a single setting, users get service-level SQL comment propagation (dddbs, ddps, etc.) plus the process-tags base hash injected as ddsh in the SQL comment and _dd.propagated_hash on the span, without needing to manage two separate variables.

Behavior:

• Same as service mode: no traceparent header, no _dd.dbm_trace_injected span tag
• Base hash (ddsh / _dd.propagated_hash) is always injected regardless of DD_DBM_INJECT_SQL_BASEHASH

Please note that this mode will replace service on the long term (and hence eventually also the DD_DBM_INJECT_SQL_BASEHASH will be deprecated/removed at same time)

Reviewer checklist

• Test coverage seems ok.
• Appropriate labels assigned.

[datadog-datadog-prod-us1]

 

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⚠️ Warnings

🚦 6 Pipeline jobs failed

DataDog/apm-reliability/dd-trace-php | ASAN test_c with multiple observers: [8.5]     

DataDog/apm-reliability/dd-trace-php | benchmarks-tracer     

DataDog/apm-reliability/dd-trace-php | helper-rust integration coverage     

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ℹ️ Info

No other issues found (see more)

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 54.12% (-0.03%)

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[pr-commenter]

Benchmarks [ tracer ]

Benchmark execution time: 2026-06-05 16:12:55

Comparing candidate commit 1c2af13 in PR branch andrea.marziali/dbm-dynamic-service with baseline commit 87f1683 in branch master.

Found 1 performance improvements and 4 performance regressions! Performance is the same for 189 metrics, 0 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

• 🟩 = significantly better candidate vs. baseline
• 🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

scenario:MessagePackSerializationBench/benchMessagePackSerialization

• 🟩 execution_time [-5.130µs; -3.850µs] or [-4.620%; -3.467%]

scenario:SamplingRuleMatchingBench/benchRegexMatching1

• 🟥 execution_time [+90.062ns; +163.738ns] or [+6.208%; +11.286%]

scenario:SamplingRuleMatchingBench/benchRegexMatching2

• 🟥 execution_time [+115.551ns; +161.649ns] or [+8.021%; +11.220%]

scenario:SamplingRuleMatchingBench/benchRegexMatching3

• 🟥 execution_time [+87.189ns; +152.011ns] or [+6.000%; +10.461%]

scenario:SamplingRuleMatchingBench/benchRegexMatching4

• 🟥 execution_time [+78.151ns; +166.249ns] or [+5.376%; +11.437%]

[bwoebi]

Looks good to me!