Accountsdb stream plugin improvement (#20419)

Support using connection pooling and use multiple threads to do Postgres db operations. The performance is improved from 1500 RPS to 40,000 RPS measured during validator start.

Support multiple plugins at the same time.

validator/src/main.rs

@@ -1221,6 +1221,7 @@ pub fn main() {
                 .long("accountsdb-plugin-config")
                 .value_name("FILE")
                 .takes_value(true)
+                .multiple(true)
                 .hidden(true)
                 .help("Specify the configuration file for the AccountsDb plugin."),
         )
@@ -1973,9 +1974,16 @@ pub fn main() {
         None
     };
 
-    let accountsdb_plugin_config_file = matches
-        .value_of("accountsdb_plugin_config")
-        .map(PathBuf::from);
+    let accountsdb_plugin_config_files = if matches.is_present("accountsdb_plugin_config") {
+        Some(
+            values_t_or_exit!(matches, "accountsdb_plugin_config", String)
+                .into_iter()
+                .map(PathBuf::from)
+                .collect(),
+        )
+    } else {
+        None
+    };
 
     let mut validator_config = ValidatorConfig {
         require_tower: matches.is_present("require_tower"),
@@ -2018,7 +2026,7 @@ pub fn main() {
             rpc_scan_and_fix_roots: matches.is_present("rpc_scan_and_fix_roots"),
         },
         accountsdb_repl_service_config,
-        accountsdb_plugin_config_file,
+        accountsdb_plugin_config_files,
         rpc_addrs: value_t!(matches, "rpc_port", u16).ok().map(|rpc_port| {
             (
                 SocketAddr::new(rpc_bind_address, rpc_port),