postgres_exporter: expose stat_statements.include_query

CHANGELOG.md

@@ -66,6 +66,8 @@ Main (unreleased)
 
 - Add `encoding.url_encode` and `encoding.url_decode` std lib functions. (@kalleep)
 
+- Add a `stat_statements` configuration block to the `prometheus.exporter.postgres` component to enable selecting both the query ID and the full SQL statement. The new block includes one option to enable statement selection, and another to configure the maximum length of the statement text. (@SimonSerrano) 
+
 ### Enhancements
 
 - Fix `pyroscope.write` component's `AppendIngest` method to respect configured timeout and implement retry logic. The method now properly uses the configured `remote_timeout`, includes retry logic with exponential backoff, and tracks metrics for sent/dropped bytes and profiles consistently with the `Append` method. (@korniltsev)

docs/sources/reference/components/prometheus/prometheus.exporter.postgres.md

@@ -122,6 +122,16 @@ If `enabled` is set to `true` and no allowlist or denylist is specified, the exp
 
 If `autodiscovery` is disabled, neither `database_allowlist` nor `database_denylist` has any effect.
 
+### `stat_statements`
+
+The `stat_statements` block configures the selection of both the query ID and the full SQL statement. This configuration takes effect only when the `stat_statements` collector is enabled.
+
+The following aeguments are supported:
+| Name                 | Type           | Description                                                                    | Default | Required |
+|----------------------|----------------|--------------------------------------------------------------------------------|---------|----------|
+| `include_query`      | `bool`         | Enable the selection of query ID and SQL statement.                            | `false` | no       |
+| `query_length`       | `number`       | Maximum length of the statement query text.                                    | `200`   | no       |
+
 ## Exported fields
 
 {{< docs/shared lookup="reference/components/exporter-component-exports.md" source="alloy" version="<ALLOY_VERSION>" >}}

internal/component/prometheus/exporter/postgres/postgres.go

@@ -37,6 +37,10 @@ var DefaultArguments = Arguments{
 	},
 	DisableDefaultMetrics:   false,
 	CustomQueriesConfigPath: "",
+	StatStatementFlags: StatStatementFlags{
+		IncludeQuery: false,
+		QueryLength:  120,
+	},
 }
 
 // Arguments configures the prometheus.exporter.postgres component
@@ -53,7 +57,8 @@ type Arguments struct {
 	EnabledCollectors       []string `alloy:"enabled_collectors,attr,optional"`
 
 	// Blocks
-	AutoDiscovery AutoDiscovery `alloy:"autodiscovery,block,optional"`
+	AutoDiscovery      AutoDiscovery      `alloy:"autodiscovery,block,optional"`
+	StatStatementFlags StatStatementFlags `alloy:"stat_statements,block,optional"`
 }
 
 func (a *Arguments) Validate() error {
@@ -73,6 +78,12 @@ type AutoDiscovery struct {
 	DatabaseDenylist  []string `alloy:"database_denylist,attr,optional"`
 }
 
+// StatStatementFlags describe the flags to pass along the activation of the stat_statements collector
+type StatStatementFlags struct {
+	IncludeQuery bool `alloy:"include_query,attr,optional"`
+	QueryLength  uint `alloy:"query_length,attr,optional"`
+}
+
 // SetToDefault implements syntax.Defaulter.
 func (a *Arguments) SetToDefault() {
 	*a = DefaultArguments
@@ -89,6 +100,8 @@ func (a *Arguments) convert(instanceName string) *postgres_exporter.Config {
 		QueryPath:              a.CustomQueriesConfigPath,
 		Instance:               instanceName,
 		EnabledCollectors:      a.EnabledCollectors,
+		IncludeQuery:           a.StatStatementFlags.IncludeQuery,
+		QueryLength:            a.StatStatementFlags.QueryLength,
 	}
 }
 

internal/component/prometheus/exporter/postgres/postgres_test.go

@@ -16,6 +16,11 @@ func TestAlloyConfigUnmarshal(t *testing.T) {
 	disable_settings_metrics = true
 	disable_default_metrics = true
 	custom_queries_config_path = "/tmp/queries.yaml"
+
+	stat_statements {
+	  include_query = true
+		query_length = 200
+	}
 
 	autodiscovery {
 		enabled = false
@@ -37,6 +42,10 @@ func TestAlloyConfigUnmarshal(t *testing.T) {
 		},
 		DisableDefaultMetrics:   true,
 		CustomQueriesConfigPath: "/tmp/queries.yaml",
+		StatStatementFlags: StatStatementFlags{
+			IncludeQuery: true,
+			QueryLength:  200,
+		},
 	}
 
 	require.Equal(t, expected, args)

internal/static/integrations/postgres_exporter/postgres_exporter.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"strings"
 
+	"github.com/alecthomas/kingpin/v2"
 	"github.com/go-kit/log"
 	"github.com/grafana/alloy/internal/runtime/logging"
 	"github.com/grafana/alloy/internal/static/integrations"
@@ -39,6 +40,9 @@ type Config struct {
 	// this is only used for the first DSN provided and only some collectors can be enabled/disabled this way. See the
 	// user-facing docs for more information.
 	EnabledCollectors []string
+
+	IncludeQuery bool
+	QueryLength  uint
 }
 
 // Name returns the name of the integration this config is for.
@@ -173,6 +177,20 @@ func New(log log.Logger, cfg *Config) (integrations.Integration, error) {
 		return integrations.NewCollectorIntegration(cfg.Name(), integrations.WithCollectors(e)), nil
 	}
 
+	// This is a hack to force the command line flag values for the stat_statements collector.
+	// These flags are not exposed outside the package and cannot be mutated afterwards.
+	if cfg.IncludeQuery {
+		iqf := kingpin.CommandLine.GetFlag("collector.stat_statements.include_query")
+		qlf := kingpin.CommandLine.GetFlag("collector.stat_statements.query_length")
+
+		if iqf == nil || qlf == nil {
+			return nil, fmt.Errorf("failed to find collector.stat_statements.include_query or collector.stat_statements.query_length in postgres_exporter")
+		}
+
+		iqf.Model().Value.Set("true")
+		qlf.Model().Value.Set(fmt.Sprintf("%d", cfg.QueryLength))
+	}
+
 	// On top of the exporter's metrics, the postgres exporter also has metrics exposed via collector package.
 	// However, these can only work for the first DSN provided. This matches the current implementation of the exporter.
 	// TODO: Once https://github.com/prometheus-community/postgres_exporter/issues/999 is addressed, update the exporter