feat(PDO): correct a bug on prepared statement regarding DBM correlation

[Leiyks]

Description

Problem

DBM correlation was broken for PDO prepared statements. The traceparent SQL comment which DBM uses to correlate database queries with APM traces contained a span_id that didn't match the span representing the actual query execution.

Root Cause
When using prepared statements (PDO::prepare() + PDOStatement::execute()):

• PDO::prepare() created a "PDO.prepare" span and injected traceparent with that span's ID
• PDOStatement::execute() created a separate "PDOStatement.execute" span as a sibling
• Mismatch: traceparent referenced the prepare span, but the actual query execution happened in the execute span

This prevented DBM from properly correlating database queries with their corresponding APM spans.

Solution
Following the RFC we now use SERVICE mode (DBM_PROPAGATION_SERVICE) for prepared statements instead of FULL mode.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.64%. Comparing base (98a31cb) to head (c45a6f6).
⚠️ Report is 8 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3545      +/-   ##
==========================================
- Coverage   61.78%   61.64%   -0.14%     
==========================================
  Files         139      139              
  Lines       13051    13051              
  Branches     1712     1712              
==========================================
- Hits         8063     8045      -18     
- Misses       4225     4241      +16     
- Partials      763      765       +2     

see 4 files with indirect coverage changes

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[pr-commenter]

Benchmarks [ tracer ]

Benchmark execution time: 2025-12-30 17:21:12

Comparing candidate commit 753738a in PR branch leiyks/APMS-17965 with baseline commit 575faf4 in branch master.

Found 5 performance improvements and 8 performance regressions! Performance is the same for 180 metrics, 1 unstable metrics.

scenario:MessagePackSerializationBench/benchMessagePackSerialization

• 🟥 execution_time [+3.317µs; +6.523µs] or [+3.247%; +6.385%]

scenario:MessagePackSerializationBench/benchMessagePackSerialization-opcache

• 🟥 execution_time [+14.734µs; +15.686µs] or [+14.587%; +15.529%]

scenario:PDOBench/benchPDOOverhead

• 🟩 execution_time [-152.434µs; -149.390µs] or [-69.194%; -67.812%]

scenario:PDOBench/benchPDOOverhead-opcache

• 🟩 execution_time [-148.277µs; -145.555µs] or [-68.261%; -67.008%]

scenario:PDOBench/benchPDOOverheadWithDBM

• 🟩 execution_time [-153.686µs; -150.072µs] or [-69.428%; -67.795%]

scenario:PDOBench/benchPDOOverheadWithDBM-opcache

• 🟩 execution_time [-147.870µs; -145.800µs] or [-68.152%; -67.198%]

scenario:SamplingRuleMatchingBench/benchGlobMatching1

• 🟥 execution_time [+44.315ns; +122.885ns] or [+2.016%; +5.591%]

scenario:SamplingRuleMatchingBench/benchRegexMatching1

• 🟥 execution_time [+91.066ns; +162.734ns] or [+7.738%; +13.827%]

scenario:SamplingRuleMatchingBench/benchRegexMatching2

• 🟥 execution_time [+123.070ns; +194.130ns] or [+10.536%; +16.619%]

scenario:SamplingRuleMatchingBench/benchRegexMatching3

• 🟥 execution_time [+120.767ns; +192.633ns] or [+10.277%; +16.393%]

scenario:SamplingRuleMatchingBench/benchRegexMatching4

• 🟥 execution_time [+118.031ns; +162.569ns] or [+10.193%; +14.039%]

scenario:SpanBench/benchOpenTelemetryAPI

• 🟥 mem_peak [+1.700MB; +1.706MB] or [+4.115%; +4.128%]

scenario:TraceSerializationBench/benchSerializeTrace

• 🟩 execution_time [-36.572µs; -26.928µs] or [-8.107%; -5.969%]