Optimize mysql and postgresql for write IO

[perso/Immae/Config/Nix.git] / modules / private / databases / postgresql.nix

diff --git a/modules/private/databases/postgresql.nix b/modules/private/databases/postgresql.nix
index 911a6d1b2a22ddfac33cf6965db78d7d3b619974..3dcd311798f7232166537cffc1c707f92dddfc50 100644 (file)
--- a/modules/private/databases/postgresql.nix
+++ b/modules/private/databases/postgresql.nix
@@ -5,7 +5,7 @@ in {
   options.myServices.databases = {
     postgresql = {
       enable = lib.mkOption {
-        default = cfg.enable;
+        default = false;
         example = true;
         description = "Whether to enable postgresql database";
         type = lib.types.bool;
@@ -121,6 +121,27 @@ in {
       SupplementaryGroups = "keys";
       RuntimeDirectory = cfg.systemdRuntimeDirectory;
     };
+    systemd.services.postgresql.postStart = lib.mkAfter ''
+      # This line is already defined in 19.09
+      PSQL="${pkgs.sudo}/bin/sudo -u postgres psql --port=5432"
+
+      ${builtins.concatStringsSep "\n" (lib.mapAttrsToList (role: _: ''
+        $PSQL -tAc "SELECT 1 FROM pg_roles WHERE rolname='${role}'" \
+            | grep -q 1 \
+            || $PSQL -tAc 'CREATE USER "${role}" WITH REPLICATION'
+        '') cfg.replicationHosts)}
+
+      ${builtins.concatStringsSep "\n" (lib.mapAttrsToList (role: _:
+        let
+          sname = builtins.replaceStrings ["-"] ["_"] role;
+        in
+        ''
+        $PSQL -tAc "SELECT 1 FROM pg_replication_slots WHERE slot_name='${sname}'" \
+              | grep -q 1 \
+              || $PSQL -tAc "SELECT * FROM pg_create_physical_replication_slot('${sname}')"
+        '') cfg.replicationHosts)}
+      '';
+
     services.postgresql = {
       enable = true;
       package = cfg.package;
@@ -140,6 +161,9 @@ in {
         lc_numeric = 'en_US.UTF-8'
         lc_time = 'en_US.UTF-8'
         default_text_search_config = 'pg_catalog.english'
+        # this introduces a small delay before storing on disk, but
+        # makes it order of magnitudes quicker
+        synchronous_commit = off
         ssl = on
         ssl_cert_file = '${config.security.acme.directory}/postgresql/fullchain.pem'
         ssl_key_file = '${config.security.acme.directory}/postgresql/key.pem'