feat(dbi): Enable PostgreSQL execution plan collection

The PostgreSQL receiver can collect query execution plans and attach them to top query events as postgresql.query_plan, but the agent pinned max_explain_each_interval to 0, which disabled collection entirely and left the attribute as an empty string.

Set it to the receiver default of 1000. The effective ceiling is top_n_query (200) plan-only operations per collection interval, since only that many queries are considered; cached plans do not consume budget, and the plan cache has a one hour TTL. EXPLAIN is issued without ANALYZE, so no query is executed.

Author: AshuSrv

translator/tocwconfig/sampleConfig/opentelemetry/combined_v1_v2_ec2_config.yaml

@@ -1292,7 +1292,7 @@ receivers:
             insecure_skip_verify: true
         top_query_collection:
             collection_interval: 1m0s
-            max_explain_each_interval: 0
+            max_explain_each_interval: 1000
             max_rows_per_query: 5000
             query_plan_cache_size: 1000
             query_plan_cache_ttl: 1h0m0s
@@ -1405,7 +1405,7 @@ receivers:
             insecure_skip_verify: true
         top_query_collection:
             collection_interval: 1m0s
-            max_explain_each_interval: 0
+            max_explain_each_interval: 1000
             max_rows_per_query: 5000
             query_plan_cache_size: 1000
             query_plan_cache_ttl: 1h0m0s

translator/tocwconfig/sampleConfig/opentelemetry/combined_v1_v2_eks_config.yaml

@@ -1863,7 +1863,7 @@ receivers:
             insecure_skip_verify: true
         top_query_collection:
             collection_interval: 1m0s
-            max_explain_each_interval: 0
+            max_explain_each_interval: 1000
             max_rows_per_query: 5000
             query_plan_cache_size: 1000
             query_plan_cache_ttl: 1h0m0s
@@ -1976,7 +1976,7 @@ receivers:
             insecure_skip_verify: true
         top_query_collection:
             collection_interval: 1m0s
-            max_explain_each_interval: 0
+            max_explain_each_interval: 1000
             max_rows_per_query: 5000
             query_plan_cache_size: 1000
             query_plan_cache_ttl: 1h0m0s

translator/tocwconfig/sampleConfig/opentelemetry/dbi_config_linux.yaml

@@ -979,7 +979,7 @@ receivers:
             insecure_skip_verify: true
         top_query_collection:
             collection_interval: 1m0s
-            max_explain_each_interval: 0
+            max_explain_each_interval: 1000
             max_rows_per_query: 5000
             query_plan_cache_size: 1000
             query_plan_cache_ttl: 1h0m0s
@@ -1092,7 +1092,7 @@ receivers:
             insecure_skip_verify: true
         top_query_collection:
             collection_interval: 1m0s
-            max_explain_each_interval: 0
+            max_explain_each_interval: 1000
             max_rows_per_query: 5000
             query_plan_cache_size: 1000
             query_plan_cache_ttl: 1h0m0s

translator/translate/otel/receiver/postgresql/translator.go

@@ -90,7 +90,7 @@ func (t *translator) Translate(_ *confmap.Conf) (component.Config, error) {
 	cfg.TopQueryCollection.CollectionInterval = 60 * time.Second
 	cfg.TopNQuery = 200
 	cfg.TopQueryCollection.MaxRowsPerQuery = 5000
-	cfg.MaxExplainEachInterval = 0
+	cfg.MaxExplainEachInterval = 1000
 
 	return cfg, nil
 }

translator/translate/otel/receiver/postgresql/translator_test.go

@@ -41,6 +41,23 @@ func TestTranslator_Translate_Defaults(t *testing.T) {
 	assert.Equal(t, int64(500), pgCfg.QuerySampleCollection.MaxRowsPerQuery)
 	assert.Equal(t, int64(200), pgCfg.TopNQuery)
 	assert.Equal(t, int64(5000), pgCfg.TopQueryCollection.MaxRowsPerQuery)
+	assert.Equal(t, int64(1000), pgCfg.MaxExplainEachInterval)
+}
+
+// Explain plan collection is disabled entirely when the budget is zero, so guard
+// against it silently regressing to that state.
+func TestTranslator_Translate_ExplainPlansEnabled(t *testing.T) {
+	tr := NewTranslator(
+		WithEndpoint("localhost:5432"),
+		WithUsername("cw_monitor"),
+		WithPassfile("/etc/.pgpass"),
+		WithIsLocalhost(true),
+	)
+	cfg, err := tr.Translate(nil)
+	require.NoError(t, err)
+	pgCfg := cfg.(*postgresqlreceiver.Config)
+
+	assert.Positive(t, pgCfg.MaxExplainEachInterval)
 }
 
 func TestTranslator_Translate_Events(t *testing.T) {