Merge pull request #141 from harshit54/schema_cache_versions

adds postgres version to the schema cache.

Author: psteinroe

crates/pg_schema_cache/src/lib.rs

@@ -4,6 +4,7 @@
 #![feature(future_join)]
 
 mod functions;
+mod versions;
 mod schema_cache;
 mod schemas;
 mod tables;

crates/pg_schema_cache/src/schema_cache.rs

@@ -6,13 +6,15 @@ use crate::functions::Function;
 use crate::schemas::Schema;
 use crate::tables::Table;
 use crate::types::PostgresType;
+use crate::versions::Version;
 
 #[derive(Debug, Clone, Default)]
 pub struct SchemaCache {
  pub schemas: Vec<Schema>,
  pub tables: Vec<Table>,
  pub functions: Vec<Function>,
  pub types: Vec<PostgresType>,
+ pub versions: Vec<Version>,
 }
 
 impl SchemaCache {
@@ -21,11 +23,12 @@ impl SchemaCache {
  }
 
  pub async fn load(pool: &PgPool) -> SchemaCache {
- let (schemas, tables, functions, types) = join!(
+ let (schemas, tables, functions, types, versions) = join!(
  Schema::load(pool),
  Table::load(pool),
  Function::load(pool),
- PostgresType::load(pool)
+ PostgresType::load(pool),
+ Version::load(pool),
  )
  .await;
 
@@ -34,6 +37,7 @@ impl SchemaCache {
  tables,
  functions,
  types,
+ versions,
  }
  }
 

crates/pg_schema_cache/src/versions.rs

@@ -0,0 +1,43 @@
+use sqlx::PgPool;
+
+use crate::schema_cache::SchemaCacheItem;
+
+#[derive(Debug, Clone, Default)]
+pub struct Version {
+ pub version: Option<String>,
+ pub version_num: Option<i64>,
+ pub active_connections: Option<i64>,
+ pub max_connections: Option<i64>,
+}
+
+impl SchemaCacheItem for Version {
+ type Item = Version;
+
+ async fn load(pool: &PgPool) -> Vec<Version> {
+ sqlx::query_as!(
+ Version,
+ r#"select
+ version(),
+ current_setting('server_version_num') :: int8 AS version_num,
+ (
+ select
+ count(*) :: int8 AS active_connections
+ FROM
+ pg_stat_activity
+ ) AS active_connections,
+ current_setting('max_connections') :: int8 AS max_connections;"#
+ )
+ .fetch_all(pool)
+ .await
+ .unwrap()
+ }
+
+ /*
+ Sample Output:
+ -[ RECORD 1 ]------+--------------------------------------------------------------------------------------------------------------------------
+ version | PostgreSQL 15.7 (Debian 15.7-1.pgdg120+1) on aarch64-unknown-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit
+ version_num | 150007
+ active_connections | 8
+ max_connections | 100
+ */
+}