Merge pull request #205 from r3dbars/codex/performance-audit-stats-query

[codex] Optimize recent stats queries

Author: r3dbars

Sources/TranscriptedCore/Stats/StatsDatabase.swift

@@ -164,9 +164,11 @@ public final class StatsDatabase {
 
         // Create indexes for common queries
         let createDateIndex = "CREATE INDEX IF NOT EXISTS idx_recordings_date ON recordings(date);"
+        let createDateTimeIndex = "CREATE INDEX IF NOT EXISTS idx_recordings_date_time ON recordings(date DESC, time DESC);"
         executeSQL(createRecordingsTable)
         executeSQL(createDailyActivityTable)
         executeSQL(createDateIndex)
+        executeSQL(createDateTimeIndex)
     }
 
     func executeSQL(_ sql: String) {
@@ -269,6 +271,41 @@ public final class StatsDatabase {
         return recordings
     }
 
+    /// Get the most recent recordings without materializing the full table.
+    public func getRecentRecordings(limit: Int) -> [RecordingMetadata] {
+        guard limit > 0 else { return [] }
+        return queue.sync {
+            getRecentRecordingsImpl(limit: limit)
+        }
+    }
+
+    private func getRecentRecordingsImpl(limit: Int) -> [RecordingMetadata] {
+        var recordings: [RecordingMetadata] = []
+
+        let sql = """
+        SELECT id, date, time, duration_seconds, word_count, speaker_count, processing_time_ms, transcript_path, title
+        FROM recordings
+        ORDER BY date DESC, time DESC
+        LIMIT ?;
+        """
+        var statement: OpaquePointer?
+
+        if sqlite3_prepare_v2(db, sql, -1, &statement, nil) == SQLITE_OK {
+            sqlite3_bind_int(statement, 1, Int32(limit))
+
+            while sqlite3_step(statement) == SQLITE_ROW {
+                if let recording = recordingMetadataFromRow(statement) {
+                    recordings.append(recording)
+                }
+            }
+        } else {
+            AppLogger.stats.error("Failed to prepare getRecentRecordings", ["sqlite_error": dbErrorMessage()])
+        }
+
+        sqlite3_finalize(statement)
+        return recordings
+    }
+
     /// Parses a RecordingMetadata from the current row of a prepared SELECT statement.
     /// Expected column order: id(0), date(1), time(2), duration_seconds(3), word_count(4),
     /// speaker_count(5), processing_time_ms(6), transcript_path(7), title(8)

Sources/TranscriptedCore/Stats/StatsService.swift

@@ -97,8 +97,7 @@ public final class StatsService: ObservableObject {
         calculateStreaks()
 
         // Get recent transcripts
-        let allRecordings = database.getAllRecordings()
-        recentTranscripts = Array(allRecordings.prefix(3))
+        recentTranscripts = database.getRecentRecordings(limit: 3)
 
         // Update motivational message
         updateMotivationalMessage()

Tests/TranscriptedCoreTests/StatsDatabaseTests.swift

@@ -0,0 +1,36 @@
+import XCTest
+@testable import TranscriptedCore
+
+@available(macOS 14.0, *)
+final class StatsDatabaseTests: XCTestCase {
+
+    func testGetRecentRecordingsHonorsLimitAndSortOrder() {
+        let databaseURL = FileManager.default.temporaryDirectory
+            .appendingPathComponent("TranscriptedCoreStatsTests-\(UUID().uuidString).sqlite")
+
+        let calendar = Calendar(identifier: .gregorian)
+        let rows = [
+            RecordingMetadata(id: "oldest", date: calendar.date(from: DateComponents(year: 2026, month: 4, day: 5, hour: 9, minute: 0))!, durationSeconds: 60),
+            RecordingMetadata(id: "middle", date: calendar.date(from: DateComponents(year: 2026, month: 4, day: 6, hour: 10, minute: 30))!, durationSeconds: 120),
+            RecordingMetadata(id: "newer", date: calendar.date(from: DateComponents(year: 2026, month: 4, day: 7, hour: 8, minute: 15))!, durationSeconds: 180),
+            RecordingMetadata(id: "newest", date: calendar.date(from: DateComponents(year: 2026, month: 4, day: 7, hour: 18, minute: 45))!, durationSeconds: 240),
+        ]
+
+        do {
+            let database = StatsDatabase(path: databaseURL.path)
+
+            for row in rows {
+                database.recordSession(row)
+            }
+            database.queue.sync {}
+
+            XCTAssertEqual(database.getRecentRecordings(limit: 2).map(\.id), ["newest", "newer"])
+            XCTAssertEqual(database.getRecentRecordings(limit: 10).map(\.id), ["newest", "newer", "middle", "oldest"])
+            XCTAssertTrue(database.getRecentRecordings(limit: 0).isEmpty)
+        }
+
+        for suffix in ["", "-shm", "-wal"] {
+            try? FileManager.default.removeItem(at: URL(fileURLWithPath: databaseURL.path + suffix))
+        }
+    }
+}