diff --git a/server/uptime-calculator.js b/server/uptime-calculator.js
index 71d1d458c..0f560a811 100644
--- a/server/uptime-calculator.js
+++ b/server/uptime-calculator.js
@@ -3,6 +3,7 @@ const { UP, MAINTENANCE, DOWN, PENDING } = require("../src/util");
 const { LimitQueue } = require("./utils/limit-queue");
 const { log } = require("../src/util");
 const { R } = require("redbean-node");
+const { Database } = require("./database");
 
 /**
  * Calculates the uptime of a monitor.
@@ -299,14 +300,23 @@ class UptimeCalculator {
         dailyStatBean.ping = dailyData.avgPing;
         dailyStatBean.pingMin = dailyData.minPing;
         dailyStatBean.pingMax = dailyData.maxPing;
+        let dailyExtras = null;
         {
             // eslint-disable-next-line no-unused-vars
             const { up, down, avgPing, minPing, maxPing, timestamp, ...extras } = dailyData;
             if (Object.keys(extras).length > 0) {
                 dailyStatBean.extras = JSON.stringify(extras);
+                dailyExtras = JSON.stringify(extras);
             }
         }
-        await R.store(dailyStatBean);
+        try {
+            await this.upsertStat("stat_daily", this.monitorID, dailyKey, 
+                dailyData.up, dailyData.down, dailyData.avgPing, 
+                dailyData.minPing, dailyData.maxPing, dailyExtras);
+        } catch (error) {
+            log.warn("uptime-calc", `Upsert failed for daily stat, falling back to R.store(): ${error.message}`);
+            await R.store(dailyStatBean);
+        }
 
         let currentDate = this.getCurrentDate();
 
@@ -319,14 +329,23 @@ class UptimeCalculator {
             hourlyStatBean.ping = hourlyData.avgPing;
             hourlyStatBean.pingMin = hourlyData.minPing;
             hourlyStatBean.pingMax = hourlyData.maxPing;
+            let hourlyExtras = null;
             {
                 // eslint-disable-next-line no-unused-vars
                 const { up, down, avgPing, minPing, maxPing, timestamp, ...extras } = hourlyData;
                 if (Object.keys(extras).length > 0) {
                     hourlyStatBean.extras = JSON.stringify(extras);
+                    hourlyExtras = JSON.stringify(extras);
                 }
             }
-            await R.store(hourlyStatBean);
+            try {
+                await this.upsertStat("stat_hourly", this.monitorID, hourlyKey, 
+                    hourlyData.up, hourlyData.down, hourlyData.avgPing, 
+                    hourlyData.minPing, hourlyData.maxPing, hourlyExtras);
+            } catch (error) {
+                log.warn("uptime-calc", `Upsert failed for hourly stat, falling back to R.store(): ${error.message}`);
+                await R.store(hourlyStatBean);
+            }
         }
 
         // For migration mode, we don't need to store old hourly and minutely data, but we need 24-hour's minutely data
@@ -338,14 +357,23 @@ class UptimeCalculator {
             minutelyStatBean.ping = minutelyData.avgPing;
             minutelyStatBean.pingMin = minutelyData.minPing;
             minutelyStatBean.pingMax = minutelyData.maxPing;
+            let minutelyExtras = null;
             {
                 // eslint-disable-next-line no-unused-vars
                 const { up, down, avgPing, minPing, maxPing, timestamp, ...extras } = minutelyData;
                 if (Object.keys(extras).length > 0) {
                     minutelyStatBean.extras = JSON.stringify(extras);
+                    minutelyExtras = JSON.stringify(extras);
                 }
             }
-            await R.store(minutelyStatBean);
+            try {
+                await this.upsertStat("stat_minutely", this.monitorID, divisionKey, 
+                    minutelyData.up, minutelyData.down, minutelyData.avgPing, 
+                    minutelyData.minPing, minutelyData.maxPing, minutelyExtras);
+            } catch (error) {
+                log.warn("uptime-calc", `Upsert failed for minutely stat, falling back to R.store(): ${error.message}`);
+                await R.store(minutelyStatBean);
+            }
         }
 
         // No need to remove old data in migration mode
@@ -386,6 +414,11 @@ class UptimeCalculator {
             bean = R.dispense("stat_daily");
             bean.monitor_id = this.monitorID;
             bean.timestamp = timestamp;
+            bean.up = 0;
+            bean.down = 0;
+            bean.ping = 0;
+            bean.pingMin = 0;
+            bean.pingMax = 0;
         }
 
         this.lastDailyStatBean = bean;
@@ -411,6 +444,11 @@ class UptimeCalculator {
             bean = R.dispense("stat_hourly");
             bean.monitor_id = this.monitorID;
             bean.timestamp = timestamp;
+            bean.up = 0;
+            bean.down = 0;
+            bean.ping = 0;
+            bean.pingMin = 0;
+            bean.pingMax = 0;
         }
 
         this.lastHourlyStatBean = bean;
@@ -436,6 +474,11 @@ class UptimeCalculator {
             bean = R.dispense("stat_minutely");
             bean.monitor_id = this.monitorID;
             bean.timestamp = timestamp;
+            bean.up = 0;
+            bean.down = 0;
+            bean.ping = 0;
+            bean.pingMin = 0;
+            bean.pingMax = 0;
         }
 
         this.lastMinutelyStatBean = bean;
@@ -516,6 +559,59 @@ class UptimeCalculator {
         return dailyKey;
     }
 
+    /**
+     * Upsert stat data using database-specific logic to handle concurrent insertions
+     * @param {string} table The stat table name (stat_daily, stat_hourly, stat_minutely)
+     * @param {number} monitorId The monitor ID
+     * @param {number} timestamp The timestamp key
+     * @param {number} up Up count
+     * @param {number} down Down count
+     * @param {number} ping Average ping
+     * @param {number} pingMin Minimum ping
+     * @param {number} pingMax Maximum ping
+     * @param {string|null} extras JSON string of extra data
+     * @returns {Promise<void>}
+     */
+    async upsertStat(table, monitorId, timestamp, up, down, ping, pingMin, pingMax, extras = null) {
+        const dbType = Database.dbConfig.type;
+
+        try {
+            if (dbType === "sqlite") {
+                await R.exec(`
+                    INSERT INTO ${table} (monitor_id, timestamp, up, down, ping, pingMin, pingMax, extras)
+                    VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+                    ON CONFLICT(monitor_id, timestamp) DO UPDATE SET
+                        up = ?,
+                        down = ?,
+                        ping = ?,
+                        pingMin = ?,
+                        pingMax = ?,
+                        extras = ?
+                `, [
+                    monitorId, timestamp, up, down, ping, pingMin, pingMax, extras,
+                    up, down, ping, pingMin, pingMax, extras
+                ]);
+            } else if (dbType.endsWith("mariadb")) {
+                await R.exec(`
+                    INSERT INTO ${table} (monitor_id, timestamp, up, down, ping, pingMin, pingMax, extras)
+                    VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+                    ON DUPLICATE KEY UPDATE
+                        up = VALUES(up),
+                        down = VALUES(down),
+                        ping = VALUES(ping),
+                        pingMin = VALUES(pingMin),
+                        pingMax = VALUES(pingMax),
+                        extras = VALUES(extras)
+                `, [monitorId, timestamp, up, down, ping, pingMin, pingMax, extras]);
+            } else {
+                throw new Error(`Unsupported database type: ${dbType}`);
+            }
+        } catch (error) {
+            log.debug("uptime-calc", `Failed to upsert ${table} for monitor ${monitorId}: ${error.message}`);
+            throw error;
+        }
+    }
+
     /**
      * Convert timestamp to key
      * @param {dayjs.Dayjs} datetime Datetime