louislam/uptime-kuma · error · Error

Aggregate table migration is already in progress

Error message

Aggregate table migration is already in progress

What it means

migrateAggregateTable() reads the Settings key 'migrateAggregateTableState'. The value 'migrating' indicates a previous run started the aggregate-table migration but never set it to 'migrated', which happens when the process was killed mid-migration. Rather than risk two concurrent migrations corrupting aggregate data, Uptime Kuma refuses to start. The warning log just above ('…or it was interrupted') tells you the same thing.

Solutions

1. Simply start the server again — if the prior migration actually completed but failed to flip the flag, a clean retry will set 'migrated'.
2. If it genuinely crashed mid-migration and the data is intact, the safest recovery is to set the flag manually: run the SQLite shell (or MariaDB client) and UPDATE the setting, e.g. `UPDATE setting SET value='migrated' WHERE key='migrateAggregateTableState';`, after confirming the aggregate tables are fully populated.
3. For 2.0.0-dev users who want to skip the migration entirely, set env `SET_MIGRATE_AGGREGATE_TABLE_TO_TRUE=1` on the next start (see database.js:858).
4. If the migration keeps failing, check disk space and the migration status server (port/hostname args to migrateAggregateTable) for the underlying error.

Example fix

# before — stuck in 'migrating' after a crash
# (server refuses to boot)

# after — reset the flag in SQLite and restart
sqlite3 ./data/kuma.db "UPDATE setting SET value='migrated' WHERE key='migrateAggregateTableState';"
npm run start

// Pre-flight: detect the stuck 'migrating' state before boot
const { Database } = require("./server/database");
const { Settings } = require("./server/settings");
async function migrationIsStuck() {
    await Database.connect(false, false, true);
    const s = await Settings.get("migrateAggregateTableState");
    return s === "migrating";
}

try {
    await Database.migrateAggregateTable(port, hostname);
} catch (e) {
    if (/already in progress/.test(e.message)) {
        // either retry once (the prior run may have finished) or, if you are certain
        // the data is consistent, set migrateAggregateTableState=migrated and restart
        log.error("startup", e.message);
        process.exit(1);
    }
    throw e;
}

When it happens

Trigger: The server was SIGKILLed, OOM-killed, or lost power during the startup aggregate-table migration (introduced for the 2.x data model). On next boot the setting still reads 'migrating' and boot aborts.

Common situations: Hard restarts during an upgrade from 1.x to 2.x; containers killed past their grace period; low-memory hosts where the OOM killer terminates node mid-migration.

Related errors

• Both and _FILE are set. Please use only one.
• Failed to read _FILE at
• Invalid db-config.json, type must be a string
• Unknown Database type
• Database connection/query failed

AI-assisted analysis of louislam/uptime-kuma@6b5ea01557 (2026-08-12). Data as JSON: /api/errors/718c84473c85487b. Report an issue: GitHub.

Appendix: source

Thrown at server/database.js:875

        // Add a setting for 2.0.0-dev users to skip this migration
        if (process.env.SET_MIGRATE_AGGREGATE_TABLE_TO_TRUE === "1") {
            log.warn(
                "db",
                "SET_MIGRATE_AGGREGATE_TABLE_TO_TRUE is set to 1, skipping aggregate table migration forever (for 2.0.0-dev users)"
            );
            await Settings.set("migrateAggregateTableState", "migrated");
        }

        let migrateState = await Settings.get("migrateAggregateTableState");

        // Skip if already migrated
        // If it is migrating, it possibly means the migration was interrupted, or the migration is in progress
        if (migrateState === "migrated") {
            log.debug("db", "Migrated aggregate table already, skip");
            return;
        } else if (migrateState === "migrating") {
            log.warn("db", "Aggregate table migration is already in progress, or it was interrupted");
            throw new Error("Aggregate table migration is already in progress");
        }

        /**
         * Start migration server for displaying the migration status
         * @type {SimpleMigrationServer}
         */
        let migrationServer;
        let msg;

        if (port) {
            migrationServer = new SimpleMigrationServer();
            await migrationServer.start(port, hostname);
        }

        log.info("db", "Migrating Aggregate Table");

        log.info("db", "Getting list of unique monitors");

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