windows_exporter/internal/collector/dns/AGENTS.md

dns collector

The collector reads the single-instance PDH object DNS with pdh.CounterTypeRaw, plus the MicrosoftDNS_Statistic class (Error Stats collection) through MI. Both exist only where the DNS Server role is installed. These notes were recorded on Windows Server 2025 (build 26100) on a domain controller that hosts AD-integrated zones and has no secondary server, so zone transfer counters stayed 0.

• The type does not tell the kind. Every X counter that has an X/sec twin is PERF_COUNTER_RAWCOUNT and cumulative, and the twin (PERF_COUNTER_COUNTER) has the same raw value (Total Query Received 830 = Total Query Received/sec 830, Dynamic Update Received 165 = its /sec twin). The help text calls the plain counters "the total number of".
• WINS Reverse Lookup Received/sec is PERF_COUNTER_RAWCOUNT despite its name.
• Gauges: the ... Memory counters ("total ... memory used by DNS server") and Total Remote Inflight Queries. The help text gives no unit for the memory counters.
• Total Query Received equals UDP Query Received + TCP Query Received (830 = 820 + 10); Total Response Sent likewise (825 = 815 + 10).
• Recursive Send TimeOuts and Recursive TimeOut/sec are a twin pair with different names; the collector reads Recursive Send TimeOuts.
• Dynamic Update Queued is cumulative: it matches Queue / Queued in dnscmd /statistics 0x00000100 (and Queued in Get-DnsServerStatistics), not the current In Queue value. Publish it as a counter.
• Eleven counters of the object have names that belong to other objects and no help text: % User Time, Async Fast Reads/sec, Fast Read Not Possibles/sec, Fast Read Resource Misses/sec, Lazy Write Flushes/sec, Lazy Write Pages/sec, Data Flushes/sec, Data Flush Pages/sec, Level 2 TLB Fills/sec, Enumerations Server/sec and Virtual Bytes. Get-Counter -ListSet DNS also lists a counter named 176. All of them stayed 0; the collector ignores them (_ fields).
• Compare live values with dnscmd /statistics or Get-Counter "\DNS\*". ipconfig /registerdns on a domain member raises the dynamic update counters.
• collectPerfData publishes one sample; test value mapping with it through a registry (see dns_internal_test.go).

Counter reference

Recorded on Windows Server 2025 (build 26100). Raw and Base are the first and second values that pdh.CounterTypeRaw returns for the sample instance.

DNS

Single-instance.

Counters the collector reads:

Counter	Type	Raw	Base
% User Time	PERF_COUNTER_COUNTER	0
Async Fast Reads/sec	PERF_COUNTER_RAWCOUNT	0
AXFR Request Received	PERF_COUNTER_RAWCOUNT	0
AXFR Request Sent	PERF_COUNTER_RAWCOUNT	0
AXFR Response Received	PERF_COUNTER_RAWCOUNT	0
AXFR Success Received	PERF_COUNTER_RAWCOUNT	0
AXFR Success Sent	PERF_COUNTER_RAWCOUNT	0
Caching Memory	PERF_COUNTER_RAWCOUNT	14216
Data Flush Pages/sec	PERF_COUNTER_RAWCOUNT	0
Data Flushes/sec	PERF_COUNTER_COUNTER	0
Database Node Memory	PERF_COUNTER_RAWCOUNT	21958
Dynamic Update NoOperation	PERF_COUNTER_RAWCOUNT	118
Dynamic Update NoOperation/sec	PERF_COUNTER_COUNTER	118
Dynamic Update Queued	PERF_COUNTER_RAWCOUNT	110
Dynamic Update Received	PERF_COUNTER_RAWCOUNT	165
Dynamic Update Received/sec	PERF_COUNTER_COUNTER	165
Dynamic Update Rejected	PERF_COUNTER_RAWCOUNT	34
Dynamic Update TimeOuts	PERF_COUNTER_RAWCOUNT	0
Dynamic Update Written to Database	PERF_COUNTER_RAWCOUNT	21
Dynamic Update Written to Database/sec	PERF_COUNTER_COUNTER	21
Enumerations Server/sec	PERF_COUNTER_COUNTER	0
Fast Read Not Possibles/sec	PERF_COUNTER_RAWCOUNT	0
Fast Read Resource Misses/sec	PERF_COUNTER_COUNTER	0
IXFR Request Received	PERF_COUNTER_RAWCOUNT	0
IXFR Request Sent	PERF_COUNTER_RAWCOUNT	0
IXFR Response Received	PERF_COUNTER_RAWCOUNT	0
IXFR Success Received	PERF_COUNTER_RAWCOUNT	0
IXFR Success Sent	PERF_COUNTER_RAWCOUNT	0
IXFR TCP Success Received	PERF_COUNTER_RAWCOUNT	0
IXFR UDP Success Received	PERF_COUNTER_RAWCOUNT	0
Lazy Write Flushes/sec	PERF_COUNTER_COUNTER	0
Lazy Write Pages/sec	PERF_COUNTER_RAWCOUNT	0
Level 2 TLB Fills/sec	PERF_COUNTER_RAWCOUNT	0
Nbstat Memory	PERF_COUNTER_RAWCOUNT	0
Notify Received	PERF_COUNTER_RAWCOUNT	0
Notify Sent	PERF_COUNTER_RAWCOUNT	0
Query Dropped Bad Socket	PERF_COUNTER_RAWCOUNT	0
Query Dropped Bad Socket/sec	PERF_COUNTER_COUNTER	0
Query Dropped By Policy	PERF_COUNTER_RAWCOUNT	0
Query Dropped By Policy/sec	PERF_COUNTER_COUNTER	0
Query Dropped By Response Rate Limiting	PERF_COUNTER_RAWCOUNT	0
Query Dropped By Response Rate Limiting/sec	PERF_COUNTER_COUNTER	0
Query Dropped Send	PERF_COUNTER_RAWCOUNT	0
Query Dropped Send/sec	PERF_COUNTER_COUNTER	0
Query Dropped Total	PERF_COUNTER_RAWCOUNT	0
Query Dropped Total/sec	PERF_COUNTER_COUNTER	0
Record Flow Memory	PERF_COUNTER_RAWCOUNT	0
Recursive Queries	PERF_COUNTER_RAWCOUNT	85
Recursive Queries/sec	PERF_COUNTER_COUNTER	85
Recursive Query Failure	PERF_COUNTER_RAWCOUNT	0
Recursive Query Failure/sec	PERF_COUNTER_COUNTER	0
Recursive Send TimeOuts	PERF_COUNTER_RAWCOUNT	0
Recursive TimeOut/sec	PERF_COUNTER_COUNTER	0
Responses Suppressed	PERF_COUNTER_RAWCOUNT	0
Responses Suppressed/sec	PERF_COUNTER_COUNTER	0
Secure Update Failure	PERF_COUNTER_RAWCOUNT	0
Secure Update Received	PERF_COUNTER_RAWCOUNT	8
Secure Update Received/sec	PERF_COUNTER_COUNTER	8
TCP Message Memory	PERF_COUNTER_RAWCOUNT	0
TCP Query Received	PERF_COUNTER_RAWCOUNT	10
TCP Query Received/sec	PERF_COUNTER_COUNTER	10
TCP Response Sent	PERF_COUNTER_RAWCOUNT	10
TCP Response Sent/sec	PERF_COUNTER_COUNTER	10
Total Query Received	PERF_COUNTER_RAWCOUNT	830
Total Query Received/sec	PERF_COUNTER_COUNTER	830
Total Remote Inflight Queries	PERF_COUNTER_RAWCOUNT	0
Total Response Sent	PERF_COUNTER_RAWCOUNT	825
Total Response Sent/sec	PERF_COUNTER_COUNTER	825
UDP Message Memory	PERF_COUNTER_RAWCOUNT	447529584
UDP Query Received	PERF_COUNTER_RAWCOUNT	820
UDP Query Received/sec	PERF_COUNTER_COUNTER	820
UDP Response Sent	PERF_COUNTER_RAWCOUNT	815
UDP Response Sent/sec	PERF_COUNTER_COUNTER	815
Unmatched Responses Received	PERF_COUNTER_RAWCOUNT	0
Virtual Bytes	PERF_COUNTER_RAWCOUNT	0
WINS Lookup Received	PERF_COUNTER_RAWCOUNT	0
WINS Lookup Received/sec	PERF_COUNTER_COUNTER	0
WINS Response Sent	PERF_COUNTER_RAWCOUNT	0
WINS Response Sent/sec	PERF_COUNTER_COUNTER	0
WINS Reverse Lookup Received	PERF_COUNTER_RAWCOUNT	0
WINS Reverse Lookup Received/sec	PERF_COUNTER_RAWCOUNT	0
WINS Reverse Response Sent	PERF_COUNTER_RAWCOUNT	0
WINS Reverse Response Sent/sec	PERF_COUNTER_COUNTER	0
Zone Transfer Failure	PERF_COUNTER_RAWCOUNT	0
Zone Transfer Request Received	PERF_COUNTER_RAWCOUNT	0
Zone Transfer SOA Request Sent	PERF_COUNTER_RAWCOUNT	0
Zone Transfer Success	PERF_COUNTER_RAWCOUNT	0