Move count stat collecting to raw SQL

PluralKit.Bot/Services/PeriodicStatCollector.cs

@@ -5,6 +5,8 @@ using System.Linq;
 using System.Threading.Tasks;
 using App.Metrics;
 
+using Dapper;
+
 using DSharpPlus;
 using DSharpPlus.Entities;
 
@@ -21,7 +23,7 @@ namespace PluralKit.Bot
         private IMetrics _metrics;
         private CpuStatService _cpu;
 
-        private IDataStore _data;
+        private Database _db;
 
         private WebhookCacheService _webhookCache;
 
@@ -29,14 +31,14 @@ namespace PluralKit.Bot
 
         private ILogger _logger;
 
-        public PeriodicStatCollector(DiscordShardedClient client, IMetrics metrics, ILogger logger, WebhookCacheService webhookCache, DbConnectionCountHolder countHolder, IDataStore data, CpuStatService cpu)
+        public PeriodicStatCollector(DiscordShardedClient client, IMetrics metrics, ILogger logger, WebhookCacheService webhookCache, DbConnectionCountHolder countHolder, CpuStatService cpu, Database db)
         {
             _client = client;
             _metrics = metrics;
             _webhookCache = webhookCache;
             _countHolder = countHolder;
-            _data = data;
             _cpu = cpu;
+            _db = db;
             _logger = logger.ForContext<PeriodicStatCollector>();
         }
 
@@ -78,10 +80,11 @@ namespace PluralKit.Bot
             _metrics.Measure.Gauge.SetValue(BotMetrics.MembersOnline, usersOnline.Count);
             
             // Aggregate DB stats
-            _metrics.Measure.Gauge.SetValue(CoreMetrics.SystemCount, await _data.GetTotalSystems());
-            _metrics.Measure.Gauge.SetValue(CoreMetrics.MemberCount, await _data.GetTotalMembers());
-            _metrics.Measure.Gauge.SetValue(CoreMetrics.SwitchCount, await _data.GetTotalSwitches());
-            _metrics.Measure.Gauge.SetValue(CoreMetrics.MessageCount, await _data.GetTotalMessages());
+            var counts = await _db.Execute(c => c.QueryFirstAsync<Counts>("select (select count(*) from systems) as systems, (select count(*) from members) as members, (select count(*) from switches) as switches, (select count(*) from messages) as messages"));
+            _metrics.Measure.Gauge.SetValue(CoreMetrics.SystemCount, counts.Systems);
+            _metrics.Measure.Gauge.SetValue(CoreMetrics.MemberCount, counts.Members);
+            _metrics.Measure.Gauge.SetValue(CoreMetrics.SwitchCount, counts.Switches);
+            _metrics.Measure.Gauge.SetValue(CoreMetrics.MessageCount, counts.Messages);
             
             // Process info
             var process = Process.GetCurrentProcess();
@@ -101,5 +104,13 @@ namespace PluralKit.Bot
             stopwatch.Stop();
             _logger.Information("Updated metrics in {Time}", stopwatch.ElapsedDuration());
         }
+
+        public class Counts
+        {
+            public int Systems { get; }
+            public int Members { get;  }
+            public int Switches { get; }
+            public int Messages { get; }
+        }
     }
 }

PluralKit.Core/Services/IDataStore.cs

@@ -283,25 +283,5 @@ namespace PluralKit.Core {
         /// Deletes all switches in a given system from the data store.
         /// </summary>
         Task DeleteAllSwitches(PKSystem system);
-
-        /// <summary>
-        /// Gets the total amount of systems in the data store.
-        /// </summary>
-        Task<ulong> GetTotalSystems();
-        
-        /// <summary>
-        /// Gets the total amount of members in the data store.
-        /// </summary>
-        Task<ulong> GetTotalMembers();
-        
-        /// <summary>
-        /// Gets the total amount of switches in the data store.
-        /// </summary>
-        Task<ulong> GetTotalSwitches();
-        
-        /// <summary>
-        /// Gets the total amount of messages in the data store.
-        /// </summary>
-        Task<ulong> GetTotalMessages();
     }
 }

PluralKit.Core/Services/PostgresDataStore.cs

@@ -1,4 +1,4 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 
@@ -113,12 +113,6 @@ namespace PluralKit.Core {
                 await conn.ExecuteAsync("delete from switches where system = @Id", system);
         }
 
-        public async Task<ulong> GetTotalSystems()
-        {
-            using (var conn = await _conn.Obtain())
-                return await conn.ExecuteScalarAsync<ulong>("select count(id) from systems");
-        }
-
         public async Task<PKMember> CreateMember(PKSystem system, string name) {
             PKMember member;
             using (var conn = await _conn.Obtain())
@@ -226,12 +220,6 @@ namespace PluralKit.Core {
             }
         }
 
-        public async Task<ulong> GetTotalMessages()
-        {
-            using (var conn = await _conn.Obtain())
-                return await conn.ExecuteScalarAsync<ulong>("select count(mid) from messages");
-        }
-
         public async Task AddSwitch(PKSystem system, IEnumerable<PKMember> members)
         {
             // Use a transaction here since we're doing multiple executed commands in one
@@ -336,12 +324,6 @@ namespace PluralKit.Core {
             _logger.Information("Deleted switch {Switch}");
         }
 
-        public async Task<ulong> GetTotalSwitches()
-        {
-            using (var conn = await _conn.Obtain())
-                return await conn.ExecuteScalarAsync<ulong>("select count(id) from switches");
-        }
-
         public async Task<IEnumerable<SwitchListEntry>> GetPeriodFronters(PKSystem system, Instant periodStart, Instant periodEnd)
         {
             // TODO: IAsyncEnumerable-ify this one