refactor: remove export_metrics feature and related configuration/docs

Author: kumarUjjawal

config/datanode.example.toml

@@ -672,20 +672,7 @@ otlp_export_protocol = "http"
 [logging.tracing_sample_ratio]
 default_ratio = 1.0
 
-## The datanode can export its metrics and send to Prometheus compatible service (e.g. `greptimedb` itself) from remote-write API.
-## This is only used for `greptimedb` to export its own metrics internally. It's different from prometheus scrape.
-[export_metrics]
-## whether enable export metrics.
-enable = false
-## The interval of export metrics.
-write_interval = "30s"
-
-[export_metrics.remote_write]
-## The prometheus remote write endpoint that the metrics send to. The url example can be: `http://127.0.0.1:4000/v1/prometheus/write?db=greptime_metrics`.
-url = ""
-
-## HTTP headers of Prometheus remote-write carry.
-headers = { }
+## Exporting internal metrics via remote-write has been removed. Please use external Prometheus/OTel/VMA to scrape metrics.
 
 ## The tracing options. Only effect when compiled with `tokio-console` feature.
 #+ [tracing]

config/frontend.example.toml

@@ -305,20 +305,7 @@ sample_ratio = 1.0
 ## The TTL of the `slow_queries` system table. Default is `90d` when `record_type` is `system_table`.
 ttl = "90d"
 
-## The frontend can export its metrics and send to Prometheus compatible service (e.g. `greptimedb` itself) from remote-write API.
-## This is only used for `greptimedb` to export its own metrics internally. It's different from prometheus scrape.
-[export_metrics]
-## whether enable export metrics.
-enable = false
-## The interval of export metrics.
-write_interval = "30s"
-
-[export_metrics.remote_write]
-## The prometheus remote write endpoint that the metrics send to. The url example can be: `http://127.0.0.1:4000/v1/prometheus/write?db=greptime_metrics`.
-url = ""
-
-## HTTP headers of Prometheus remote-write carry.
-headers = { }
+## Exporting internal metrics via remote-write has been removed. Please use external Prometheus/OTel/VMA to scrape metrics.
 
 ## The tracing options. Only effect when compiled with `tokio-console` feature.
 #+ [tracing]

config/metasrv.example.toml

@@ -325,20 +325,7 @@ otlp_export_protocol = "http"
 [logging.tracing_sample_ratio]
 default_ratio = 1.0
 
-## The metasrv can export its metrics and send to Prometheus compatible service (e.g. `greptimedb` itself) from remote-write API.
-## This is only used for `greptimedb` to export its own metrics internally. It's different from prometheus scrape.
-[export_metrics]
-## whether enable export metrics.
-enable = false
-## The interval of export metrics.
-write_interval = "30s"
-
-[export_metrics.remote_write]
-## The prometheus remote write endpoint that the metrics send to. The url example can be: `http://127.0.0.1:4000/v1/prometheus/write?db=greptime_metrics`.
-url = ""
-
-## HTTP headers of Prometheus remote-write carry.
-headers = { }
+## Exporting internal metrics via remote-write has been removed. Please use external Prometheus/OTel/VMA to scrape metrics.
 
 ## The tracing options. Only effect when compiled with `tokio-console` feature.
 #+ [tracing]

config/standalone.example.toml

@@ -768,26 +768,7 @@ default_ratio = 1.0
 ## @toml2docs:none-default
 #+ sample_ratio = 1.0
 
-## The standalone can export its metrics and send to Prometheus compatible service (e.g. `greptimedb`) from remote-write API.
-## This is only used for `greptimedb` to export its own metrics internally. It's different from prometheus scrape.
-[export_metrics]
-## whether enable export metrics.
-enable = false
-## The interval of export metrics.
-write_interval = "30s"
-
-## For `standalone` mode, `self_import` is recommended to collect metrics generated by itself
-## You must create the database before enabling it.
-[export_metrics.self_import]
-## @toml2docs:none-default
-db = "greptime_metrics"
-
-[export_metrics.remote_write]
-## The prometheus remote write endpoint that the metrics send to. The url example can be: `http://127.0.0.1:4000/v1/prometheus/write?db=greptime_metrics`.
-url = ""
-
-## HTTP headers of Prometheus remote-write carry.
-headers = { }
+## Exporting internal metrics via remote-write has been removed. Please use external Prometheus/OTel/VMA to scrape metrics.
 
 ## The tracing options. Only effect when compiled with `tokio-console` feature.
 #+ [tracing]

src/catalog/src/system_schema/information_schema.rs

@@ -22,7 +22,6 @@ mod procedure_info;
 pub mod process_list;
 pub mod region_peers;
 mod region_statistics;
-mod runtime_metrics;
 pub mod schemata;
 mod table_constraints;
 mod table_names;
@@ -60,7 +59,6 @@ use crate::system_schema::information_schema::information_memory_table::get_sche
 use crate::system_schema::information_schema::key_column_usage::InformationSchemaKeyColumnUsage;
 use crate::system_schema::information_schema::partitions::InformationSchemaPartitions;
 use crate::system_schema::information_schema::region_peers::InformationSchemaRegionPeers;
-use crate::system_schema::information_schema::runtime_metrics::InformationSchemaMetrics;
 use crate::system_schema::information_schema::schemata::InformationSchemaSchemata;
 use crate::system_schema::information_schema::table_constraints::InformationSchemaTableConstraints;
 use crate::system_schema::information_schema::tables::InformationSchemaTables;
@@ -211,7 +209,6 @@ impl SystemSchemaProviderInner for InformationSchemaProvider {
                 self.catalog_name.clone(),
                 self.catalog_manager.clone(),
             )) as _),
-            RUNTIME_METRICS => Some(Arc::new(InformationSchemaMetrics::new())),
             PARTITIONS => Some(Arc::new(InformationSchemaPartitions::new(
                 self.catalog_name.clone(),
                 self.catalog_manager.clone(),
@@ -297,10 +294,6 @@ impl InformationSchemaProvider {
         // authentication details, and other critical information.
         // Only put these tables under `greptime` catalog to prevent info leak.
         if self.catalog_name == DEFAULT_CATALOG_NAME {
-            tables.insert(
-                RUNTIME_METRICS.to_string(),
-                self.build_table(RUNTIME_METRICS).unwrap(),
-            );
             tables.insert(
                 BUILD_INFO.to_string(),
                 self.build_table(BUILD_INFO).unwrap(),