Add a gtid transaction counter based on the @@gtid_executed global variable by sjmudd · Pull Request #965 · prometheus/mysqld_exporter

sjmudd · 2025-07-16T17:28:53Z

This PR provides a simple global transaction counter which can be used to track the transaction rate on a MySQL server.

The full GTID set is combined into a single transaction count
UUIDs are ignored
Any GTID gaps are taken into account
works on MySQL 5.6+
works with MySQL 8.4+ tagged gtid format

This PR provides a simple global transaction counter which can be used to track the transaction rate on a MySQL server. - The full GTID set is combined into a single transaction count - UUIDs are ignored - Any GTID gaps are taken into account - works on MySQL 5.6+ - works with MySQL 8.4+ tagged gtid format Signed-off-by: Simon J Mudd <[email protected]>

sjmudd · 2025-07-20T19:29:18Z

Hello,

It is not very clear to me how long I should expect to wait for a response to my PR, whether positive or negative. If you could provide some sort of feedback here or in the README that would be most helpful.

sjmudd · 2025-09-08T13:48:46Z

2 months have passed. Any chance of getting this PR accepted? If you need something more from me can you tell me what it is?

ArthurSens

Hey, sorry for the super-delayed review. We are understaffed for exporter maintainers, but we're trying to catch up with our backlog 😓

I've left a few comments below. Also, we might want to rewrite the code to clarify that it's about GTID executions, not transactions, since people might get confused with regular database transactions. For example, SET gtid_purged is not a transaction at all, but counts as a GTID execution

ArthurSens · 2026-09-08T11:49:59Z

+var (
+	// Metric descriptors.
+	GtidTransactionCounterDesc = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, prometheusSubsystem, prometheusName),


Suggested change

prometheus.BuildFQName(namespace, prometheusSubsystem, prometheusName),

prometheus.BuildFQName(namespace, prometheusSubsystem,"executed_total"),

Following Prometheus naming conventions, counters should be suffixed with _total. Besides that, gtid_executed seems more accurate than gtid_transactions 🤔

ArthurSens · 2026-09-08T11:58:06Z

+	tests := []struct {
+		name     string
+		gtidSet  string
+		expected float64
+	}{
+		{"empty_set", "", 0},
+		{"single_uuid_and_range", `uuid1:1-1000`, 1000},
+		{"multiple_uuid_single_range", `uuid1:1-1000,
+	uuid1:1001-2000`, 2000},
+		{"single_uuid_with_ranges", `uuid1:1-1000,2001-4000`, 3000},
+	}


Looking at docs

GTID format, sets, intervals, and tags

gtid_executed system-variable semantics

GTID lifecycle, gaps, filtering, and resets

The test cases seems incorrect 🤔

I'd add something like

Suggested change

tests := []struct {

name string

gtidSet string

expected float64

}{

{"empty_set", "", 0},

{"single_uuid_and_range", `uuid1:1-1000`, 1000},

{"multiple_uuid_single_range", `uuid1:1-1000,

uuid1:1001-2000`, 2000},

{"single_uuid_with_ranges", `uuid1:1-1000,2001-4000`, 3000},

}

tests := []struct {

name string

gtidSet string

expected float64

expectErr bool

}{

{"empty_set", "", 0, false},

{"single_transaction", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1`, 1, false},

{"single_uuid_and_range", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-1000`, 1000, false},

{"single_uuid_with_ranges", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-3:11:47-49`, 7, false},

{"multiple_uuids", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-3,

24BC7856-9C4A-11E1-9D41-80C16E4A511C:1-10`, 13, false},

{"multiple_uuids_single_line", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-3,24BC7856-9C4A-11E1-9D41-80C16E4A511C:1-10`, 13, false},

{"tagged_gtid_with_ranges", `3E11FA47-71CA-11E1-9E33-C80AA9429562:Domain_1:1-3:11:47-49`, 7, false},

{"multiple_tags_for_same_uuid", `3E11FA47-71CA-11E1-9E33-C80AA9429562:Domain_1:1-3:15-21,

3E11FA47-71CA-11E1-9E33-C80AA9429562:Domain_2:8-52`, 55, false},

{"mixed_tagged_and_untagged_sets", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-5,

24BC7856-9C4A-11E1-9D41-80C16E4A511C:Analytics_1:10-14`, 10, false},

{"missing_uuid", `1-10`, 0, true},

{"comma_between_intervals", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-3,11-20`, 0, true},

{"reversed_range", `3E11FA47-71CA-11E1-9E33-C80AA9429562:20-10`, 0, true},

{"zero_transaction_id", `3E11FA47-71CA-11E1-9E33-C80AA9429562:0`, 0, true},

{"missing_tagged_interval", `3E11FA47-71CA-11E1-9E33-C80AA9429562:Domain_1`, 0, true},

{"invalid_tag", `3E11FA47-71CA-11E1-9E33-C80AA9429562:123tag:1-10`, 0, true},

{"transaction_id_overflow", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-9223372036854775808`, 0, true},

}```

ArthurSens · 2026-09-08T11:59:45Z

 	github.com/prometheus/client_model v0.6.2
 	github.com/prometheus/common v0.65.0
 	github.com/prometheus/exporter-toolkit v0.13.2
+	github.com/sjmudd/mysqlgtid v0.1.0


This dependency seems to parse GTID incorrectly; is there a more accurate one? It's been a few years since the PR was opened, so maybe there are newer, more accurate versions?

ArthurSens · 2026-09-08T12:00:23Z

+
+// Name of the Scraper. Should be unique.
+func (ScrapeGtidExecuted) Name() string {
+	return "gtid_transactions"


Suggested change

return "gtid_transactions"

return "gtid_executions"

ArthurSens · 2026-09-08T12:00:32Z

+
+// Help describes the role of the Scraper.
+func (ScrapeGtidExecuted) Help() string {
+	return "Number of GTID transactions"


Suggested change

return "Number of GTID transactions"

return "Number of GTID executions"

sjmudd mentioned this pull request Jul 16, 2025

Add gtid_transaction counter taken from @gtid_executed #964

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ArthurSens reviewed Sep 8, 2026

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Add a gtid transaction counter based on the @@gtid_executed global variable - #965

Add a gtid transaction counter based on the @@gtid_executed global variable#965
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	prometheus.BuildFQName(namespace, prometheusSubsystem, prometheusName),
	prometheus.BuildFQName(namespace, prometheusSubsystem,"executed_total"),

-	tests := []struct {
-		name     string
-		gtidSet  string
-		expected float64
-	}{
-		{"empty_set", "", 0},
-		{"single_uuid_and_range", `uuid1:1-1000`, 1000},
-		{"multiple_uuid_single_range", `uuid1:1-1000,
-	uuid1:1001-2000`, 2000},
-		{"single_uuid_with_ranges", `uuid1:1-1000,2001-4000`, 3000},
-	}
+	tests := []struct {
+		name      string
+		gtidSet   string
+		expected  float64
+		expectErr bool
+	}{
+		{"empty_set", "", 0, false},
+		{"single_transaction", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1`, 1, false},
+		{"single_uuid_and_range", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-1000`, 1000, false},
+		{"single_uuid_with_ranges", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-3:11:47-49`, 7, false},
+		{"multiple_uuids", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-3,
+BC7856-9C4A-11E1-9D41-80C16E4A511C:1-10`, 13, false},
+		{"multiple_uuids_single_line", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-3,24BC7856-9C4A-11E1-9D41-80C16E4A511C:1-10`, 13, false},
+		{"tagged_gtid_with_ranges", `3E11FA47-71CA-11E1-9E33-C80AA9429562:Domain_1:1-3:11:47-49`, 7, false},
+		{"multiple_tags_for_same_uuid", `3E11FA47-71CA-11E1-9E33-C80AA9429562:Domain_1:1-3:15-21,
+E11FA47-71CA-11E1-9E33-C80AA9429562:Domain_2:8-52`, 55, false},
+		{"mixed_tagged_and_untagged_sets", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-5,
+BC7856-9C4A-11E1-9D41-80C16E4A511C:Analytics_1:10-14`, 10, false},
+		{"missing_uuid", `1-10`, 0, true},
+		{"comma_between_intervals", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-3,11-20`, 0, true},
+		{"reversed_range", `3E11FA47-71CA-11E1-9E33-C80AA9429562:20-10`, 0, true},
+		{"zero_transaction_id", `3E11FA47-71CA-11E1-9E33-C80AA9429562:0`, 0, true},
+		{"missing_tagged_interval", `3E11FA47-71CA-11E1-9E33-C80AA9429562:Domain_1`, 0, true},
+		{"invalid_tag", `3E11FA47-71CA-11E1-9E33-C80AA9429562:123tag:1-10`, 0, true},
+		{"transaction_id_overflow", `3E11FA47-71CA-11E1-9E33-C80AA9429562:1-9223372036854775808`, 0, true},
+	}```

	return "Number of GTID transactions"
	return "Number of GTID executions"

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