diff --git a/.env.example b/.env.example
index eabe3c4..6e36439 100644
--- a/.env.example
+++ b/.env.example
@@ -4,6 +4,7 @@ SUPABASE_SERVICE_ROLE_KEY=
 
 NEXT_PUBLIC_APP_URL=http://localhost:3000
 JOB_SECRET=
+CRON_SECRET=
 
 ENCRYPTION_KEY=
 PLESK_CRED_ENC_KEY=
diff --git a/README.md b/README.md
index c1978d5..a6eb5e0 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,9 @@ values ('<agency_uuid>', '<auth_user_uuid>', 'owner');
 
 - `POST /api/plesk/instances` — create + validate Plesk connection
 - `POST /api/plesk/instances/:id/sync` — pull/sync subscriptions + domains from one Plesk instance
+- `POST /api/plesk/instances/:id/autosync` — update auto-sync enabled/frequency for one Plesk instance
 - `POST /api/jobs/plesk-sync-all` — background sync job for all connected instances (requires `X-JOB-SECRET`)
+- `POST /api/cron/autosync` — scheduled auto-sync tick (requires `X-CRON-SECRET`)
 - `POST /api/plesk/subscriptions/:id/action` — suspend or unsuspend
 - `POST /api/stripe/checkout` — create Stripe Checkout session
 - `POST /api/stripe/portal` — create Stripe Customer Portal session
@@ -74,6 +76,7 @@ values ('<agency_uuid>', '<auth_user_uuid>', 'owner');
 - Set a strong `ENCRYPTION_KEY`; it encrypts stored Plesk auth secrets.
 - Set a strong `PLESK_CRED_ENC_KEY` (32-byte base64 or 64-char hex) for Plesk credential encryption.
 - Set `JOB_SECRET` for internal cron-triggered job auth.
+- Set `CRON_SECRET` for `/api/cron/autosync` auth.
 - `/api/stripe/webhook` is excluded from auth middleware for Stripe signature verification.
 - Current implementation is intentionally MVP-focused; add stronger validation, retries, idempotency keys, and richer error observability for production.
 
@@ -97,3 +100,37 @@ Notes:
 - Job uses DB lock (`job_locks`) to avoid overlapping runs.
 - Job processes at most 10 connected instances per run.
 - Instances synced in the last 3 minutes are skipped.
+
+## 6) Auto Sync Worker (CL6)
+
+New scheduler fields live on `plesk_instances`:
+
+- `auto_sync_enabled`
+- `auto_sync_frequency_minutes`
+- `last_auto_sync_at`
+- `next_auto_sync_at`
+- `auto_sync_lock_until`
+- `auto_sync_lock_token`
+
+Endpoint for periodic worker ticks:
+
+```bash
+curl -sS -X POST http://localhost:3000/api/cron/autosync \
+  -H "X-CRON-SECRET: <CRON_SECRET>"
+```
+
+Recommended system cron (every 5 minutes):
+
+```cron
+*/5 * * * * curl -sS -X POST https://<your-host>/api/cron/autosync -H "X-CRON-SECRET: ${CRON_SECRET}"
+```
+
+Or schedule the same call from Jenkins.
+
+Worker safety behavior:
+
+- processes at most 5 instances per tick
+- concurrency limited to 2 at a time
+- per-instance lock lease 15 minutes
+- per-instance timeout guard 14 minutes
+- per-instance failures are isolated and logged to `actions_log`
diff --git a/app/api/cron/autosync/route.ts b/app/api/cron/autosync/route.ts
new file mode 100644
index 0000000..f8d17a0
--- /dev/null
+++ b/app/api/cron/autosync/route.ts
@@ -0,0 +1,38 @@
+import { NextResponse } from "next/server";
+
+import { env } from "@/lib/env";
+import { runAutoSyncTick } from "@/lib/plesk/auto-sync";
+import { createSupabaseAdminClient } from "@/lib/supabase/admin";
+
+export async function POST(req: Request) {
+  const startedAt = Date.now();
+
+  try {
+    const secret = req.headers.get("x-cron-secret");
+    if (!env.cronSecret || !secret || secret !== env.cronSecret) {
+      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+    }
+
+    const supabase = createSupabaseAdminClient() as any;
+    const summary = await runAutoSyncTick(supabase);
+
+    return NextResponse.json({
+      ...summary,
+      duration_ms: Date.now() - startedAt,
+    });
+  } catch (error) {
+    console.error("[autosync cron] failed", error);
+
+    return NextResponse.json(
+      {
+        error: "Auto-sync job failed",
+        instances_considered: 0,
+        locks_acquired: 0,
+        succeeded: 0,
+        failed: 0,
+        duration_ms: Date.now() - startedAt,
+      },
+      { status: 500 },
+    );
+  }
+}
diff --git a/app/api/plesk/instances/[id]/autosync/route.ts b/app/api/plesk/instances/[id]/autosync/route.ts
new file mode 100644
index 0000000..8321be9
--- /dev/null
+++ b/app/api/plesk/instances/[id]/autosync/route.ts
@@ -0,0 +1,87 @@
+import { NextResponse } from "next/server";
+import { z } from "zod";
+
+import { assertAgencyAdmin, getRouteAgencyContextOrThrow } from "@/lib/agency";
+import { assertRateLimit } from "@/lib/api/rate-limit";
+import { assertSameOrigin } from "@/lib/api/security";
+import { createSupabaseRouteClient } from "@/lib/supabase/route";
+
+const autosyncSchema = z.object({
+  auto_sync_enabled: z.boolean(),
+  auto_sync_frequency_minutes: z.number().int().min(5).max(10080).optional(),
+});
+
+export async function POST(
+  req: Request,
+  { params }: { params: { id: string } },
+) {
+  try {
+    assertSameOrigin(req);
+
+    const context = await getRouteAgencyContextOrThrow();
+    assertAgencyAdmin(context);
+    assertRateLimit(`plesk-autosync-settings:${context.userId}`, 20, 60_000);
+
+    const input = autosyncSchema.parse(await req.json());
+    const frequency = input.auto_sync_frequency_minutes ?? 60;
+    const nowIso = new Date().toISOString();
+    const nextAtIso = new Date(
+      Date.now() + frequency * 60 * 1000,
+    ).toISOString();
+
+    const supabase = createSupabaseRouteClient() as any;
+
+    const updates = {
+      auto_sync_enabled: input.auto_sync_enabled,
+      auto_sync_frequency_minutes: frequency,
+      next_auto_sync_at: input.auto_sync_enabled ? nextAtIso : null,
+      auto_sync_lock_until: null,
+      auto_sync_lock_token: null,
+      last_auto_sync_at: input.auto_sync_enabled ? undefined : null,
+    } as Record<string, unknown>;
+
+    const { data: instance, error } = await supabase
+      .from("plesk_instances")
+      .update(updates)
+      .eq("id", params.id)
+      .eq("agency_id", context.agencyId)
+      .select(
+        "id, auto_sync_enabled, auto_sync_frequency_minutes, last_auto_sync_at, next_auto_sync_at, auto_sync_lock_until",
+      )
+      .single();
+
+    if (error || !instance) {
+      throw new Error(error?.message ?? "Plesk instance not found");
+    }
+
+    try {
+      await supabase.from("actions_log").insert({
+        agency_id: context.agencyId,
+        actor_user_id: context.userId,
+        target_type: "plesk_instance",
+        target_id: params.id,
+        action: "autosync_settings_updated",
+        status: "success",
+        metadata: {
+          auto_sync_enabled: input.auto_sync_enabled,
+          auto_sync_frequency_minutes: frequency,
+          updated_at: nowIso,
+        },
+      });
+    } catch {
+      // best effort logging
+    }
+
+    return NextResponse.json({ instance });
+  } catch (error) {
+    return NextResponse.json(
+      {
+        error:
+          error instanceof Error
+            ? error.message
+            : "Failed to update auto-sync settings",
+      },
+      { status: 400 },
+    );
+  }
+}
diff --git a/app/dashboard/page.tsx b/app/dashboard/page.tsx
index c785cbf..f82bb2a 100644
--- a/app/dashboard/page.tsx
+++ b/app/dashboard/page.tsx
@@ -57,7 +57,7 @@ export default async function DashboardPage() {
     supabase
       .from("plesk_instances")
       .select(
-        "id, name, base_url, auth_type, status, error_message, last_connected_at, last_sync_at, last_sync_status, last_sync_error, last_sync_subscriptions, last_sync_domains",
+        "id, name, base_url, auth_type, status, error_message, last_connected_at, last_sync_at, last_sync_status, last_sync_error, last_sync_subscriptions, last_sync_domains, auto_sync_enabled, auto_sync_frequency_minutes, last_auto_sync_at, next_auto_sync_at, auto_sync_lock_until",
       )
       .eq("agency_id", context.agencyId)
       .order("created_at", { ascending: false }),
@@ -104,6 +104,11 @@ export default async function DashboardPage() {
         last_sync_error: string | null;
         last_sync_subscriptions: number;
         last_sync_domains: number;
+        auto_sync_enabled: boolean;
+        auto_sync_frequency_minutes: number;
+        last_auto_sync_at: string | null;
+        next_auto_sync_at: string | null;
+        auto_sync_lock_until: string | null;
       }> | null;
       error: { message: string } | null;
     },
diff --git a/components/dashboard/dashboard-controls.tsx b/components/dashboard/dashboard-controls.tsx
index 5a639d2..6e493ec 100644
--- a/components/dashboard/dashboard-controls.tsx
+++ b/components/dashboard/dashboard-controls.tsx
@@ -18,6 +18,11 @@ type Instance = {
   last_sync_error: string | null;
   last_sync_subscriptions: number;
   last_sync_domains: number;
+  auto_sync_enabled: boolean;
+  auto_sync_frequency_minutes: number;
+  last_auto_sync_at: string | null;
+  next_auto_sync_at: string | null;
+  auto_sync_lock_until: string | null;
 };
 
 type Subscription = {
@@ -116,6 +121,7 @@ export function DashboardControls({
   domains,
   autoSyncByInstance,
 }: Props) {
+  const autoSyncFrequencyOptions = [15, 30, 60, 180, 360, 1440];
   const [instanceName, setInstanceName] = useState("");
   const [baseUrl, setBaseUrl] = useState("");
   const [authType, setAuthType] = useState<"api_key" | "basic">("api_key");
@@ -239,6 +245,25 @@ export function DashboardControls({
     }
   }
 
+  async function onUpdateAutoSync(
+    instanceId: string,
+    input: { auto_sync_enabled: boolean; auto_sync_frequency_minutes: number },
+  ) {
+    setLoading(true);
+    setMessage(null);
+    try {
+      await runRequest(`/api/plesk/instances/${instanceId}/autosync`, input);
+      setMessage("Auto-sync settings updated.");
+      window.location.reload();
+    } catch (error) {
+      setMessage(
+        error instanceof Error ? error.message : "Auto-sync update failed",
+      );
+    } finally {
+      setLoading(false);
+    }
+  }
+
   async function onSubscriptionAction() {
     if (!actionSubId) return;
     setLoading(true);
@@ -470,6 +495,30 @@ export function DashboardControls({
                           ? formatDateTime(instance.last_connected_at)
                           : "never"}
                       </p>
+                      <p className="text-xs text-slate-500">
+                        Auto-sync:{" "}
+                        {instance.auto_sync_enabled ? "Enabled" : "Disabled"}
+                      </p>
+                      <p className="text-xs text-slate-500">
+                        Auto-sync frequency:{" "}
+                        {instance.auto_sync_frequency_minutes ?? 60} min
+                      </p>
+                      <p className="text-xs text-slate-500">
+                        Last auto-sync:{" "}
+                        {formatDateTime(instance.last_auto_sync_at)}
+                      </p>
+                      <p className="text-xs text-slate-500">
+                        Next auto-sync:{" "}
+                        {formatDateTime(instance.next_auto_sync_at)}
+                      </p>
+                      <p className="text-xs text-slate-500">
+                        Lock status:{" "}
+                        {instance.auto_sync_lock_until &&
+                        new Date(instance.auto_sync_lock_until).getTime() >
+                          Date.now()
+                          ? "Sync in progress"
+                          : "Idle"}
+                      </p>
                       {autoSyncByInstance[instance.id] ? (
                         <p className="text-xs text-slate-500">
                           Last auto-sync:{" "}
@@ -496,6 +545,42 @@ export function DashboardControls({
                       ) : null}
                     </div>
                     <div className="flex flex-col gap-2">
+                      <div className="flex items-center gap-2">
+                        <label className="text-xs text-slate-600">
+                          Auto-sync
+                        </label>
+                        <input
+                          type="checkbox"
+                          checked={instance.auto_sync_enabled}
+                          onChange={(e: ChangeEvent<HTMLInputElement>) =>
+                            onUpdateAutoSync(instance.id, {
+                              auto_sync_enabled: e.target.checked,
+                              auto_sync_frequency_minutes:
+                                instance.auto_sync_frequency_minutes ?? 60,
+                            })
+                          }
+                          disabled={loading}
+                        />
+                      </div>
+                      <select
+                        value={String(
+                          instance.auto_sync_frequency_minutes ?? 60,
+                        )}
+                        onChange={(e: ChangeEvent<HTMLSelectElement>) =>
+                          onUpdateAutoSync(instance.id, {
+                            auto_sync_enabled: instance.auto_sync_enabled,
+                            auto_sync_frequency_minutes: Number(e.target.value),
+                          })
+                        }
+                        disabled={loading}
+                        className="rounded border px-2 py-1 text-xs"
+                      >
+                        {autoSyncFrequencyOptions.map((minutes) => (
+                          <option key={minutes} value={minutes}>
+                            Every {minutes} min
+                          </option>
+                        ))}
+                      </select>
                       <button
                         onClick={() => onTestConnection(instance.id)}
                         disabled={loading}
diff --git a/lib/env.ts b/lib/env.ts
index 17a3044..b809dbe 100644
--- a/lib/env.ts
+++ b/lib/env.ts
@@ -14,6 +14,7 @@ for (const key of requiredEnvs) {
 export const env = {
   appUrl: process.env.NEXT_PUBLIC_APP_URL ?? "http://localhost:3000",
   jobSecret: process.env.JOB_SECRET ?? "",
+  cronSecret: process.env.CRON_SECRET ?? "",
   encryptionKey: process.env.ENCRYPTION_KEY ?? "",
   pleskCredEncKey: process.env.PLESK_CRED_ENC_KEY ?? "",
   stripeSecretKey: process.env.STRIPE_SECRET_KEY ?? "",
diff --git a/lib/plesk/auto-sync.ts b/lib/plesk/auto-sync.ts
new file mode 100644
index 0000000..dee91fc
--- /dev/null
+++ b/lib/plesk/auto-sync.ts
@@ -0,0 +1,232 @@
+import { randomUUID } from "crypto";
+
+import { syncPleskInstance } from "@/lib/plesk/sync";
+
+type SupabaseLike = any;
+
+type AutoSyncInstance = {
+  id: string;
+  agency_id: string;
+  base_url: string;
+  auth_type: "api_key" | "basic";
+  encrypted_secret: string;
+  last_connected_at: string | null;
+  auto_sync_enabled: boolean;
+  auto_sync_frequency_minutes: number | null;
+  next_auto_sync_at: string | null;
+  auto_sync_lock_until: string | null;
+};
+
+type AutoSyncSummary = {
+  instances_considered: number;
+  locks_acquired: number;
+  succeeded: number;
+  failed: number;
+  duration_ms: number;
+};
+
+const MAX_INSTANCES_PER_TICK = 5;
+const MAX_CONCURRENCY = 2;
+const LOCK_LEASE_SECONDS = 15 * 60;
+const INSTANCE_TIMEOUT_MS = 14 * 60 * 1000;
+
+function isDue(instance: AutoSyncInstance, now: number) {
+  if (!instance.next_auto_sync_at) return true;
+  const dueAt = new Date(instance.next_auto_sync_at).getTime();
+  return Number.isFinite(dueAt) && dueAt <= now;
+}
+
+function isUnlocked(instance: AutoSyncInstance, now: number) {
+  if (!instance.auto_sync_lock_until) return true;
+  const lockUntil = new Date(instance.auto_sync_lock_until).getTime();
+  return !Number.isFinite(lockUntil) || lockUntil <= now;
+}
+
+async function insertActionLogBestEffort(
+  supabase: SupabaseLike,
+  payload: Record<string, unknown>,
+) {
+  try {
+    const { error } = await supabase.from("actions_log").insert(payload);
+    if (error) {
+      console.error("[autosync] actions_log insert failed", error.message);
+    }
+  } catch (error) {
+    console.error("[autosync] actions_log insert threw", error);
+  }
+}
+
+async function withTimeout<T>(
+  promise: Promise<T>,
+  timeoutMs: number,
+): Promise<T> {
+  let timeout: ReturnType<typeof setTimeout> | null = null;
+
+  const timeoutPromise = new Promise<never>((_, reject) => {
+    timeout = setTimeout(() => {
+      reject(new Error("Auto-sync timed out"));
+    }, timeoutMs);
+  });
+
+  try {
+    return await Promise.race([promise, timeoutPromise]);
+  } finally {
+    if (timeout) clearTimeout(timeout);
+  }
+}
+
+export async function runAutoSyncTick(
+  supabase: SupabaseLike,
+): Promise<AutoSyncSummary> {
+  const startedAt = Date.now();
+  const now = Date.now();
+
+  const { data: rows, error } = await supabase
+    .from("plesk_instances")
+    .select(
+      "id, agency_id, base_url, auth_type, encrypted_secret, last_connected_at, auto_sync_enabled, auto_sync_frequency_minutes, next_auto_sync_at, auto_sync_lock_until",
+    )
+    .eq("status", "connected")
+    .eq("auto_sync_enabled", true)
+    .order("next_auto_sync_at", { ascending: true, nullsFirst: true })
+    .limit(50);
+
+  if (error) {
+    throw new Error(error.message);
+  }
+
+  const eligible = ((rows ?? []) as AutoSyncInstance[])
+    .filter((instance) => isDue(instance, now) && isUnlocked(instance, now))
+    .slice(0, MAX_INSTANCES_PER_TICK);
+
+  let locksAcquired = 0;
+  let succeeded = 0;
+  let failed = 0;
+
+  const queue = [...eligible];
+
+  async function processInstance(instance: AutoSyncInstance) {
+    const lockToken = randomUUID();
+    const { data: lockAcquired, error: lockError } = await supabase.rpc(
+      "acquire_instance_auto_sync_lock",
+      {
+        p_instance_id: instance.id,
+        p_lock_token: lockToken,
+        p_ttl_seconds: LOCK_LEASE_SECONDS,
+      },
+    );
+
+    if (lockError || !lockAcquired) return;
+    locksAcquired += 1;
+
+    const perInstanceStartedAt = Date.now();
+    const frequencyMinutes = Math.max(
+      instance.auto_sync_frequency_minutes ?? 60,
+      5,
+    );
+
+    await insertActionLogBestEffort(supabase, {
+      agency_id: instance.agency_id,
+      actor_user_id: null,
+      target_type: "plesk_instance",
+      target_id: instance.id,
+      action: "autosync_started",
+      status: "pending",
+      metadata: {
+        instance_id: instance.id,
+        lock_token: lockToken,
+        frequency_minutes: frequencyMinutes,
+      },
+    });
+
+    try {
+      await withTimeout(
+        syncPleskInstance(supabase, instance, null, "autosync"),
+        INSTANCE_TIMEOUT_MS,
+      );
+
+      succeeded += 1;
+
+      await insertActionLogBestEffort(supabase, {
+        agency_id: instance.agency_id,
+        actor_user_id: null,
+        target_type: "plesk_instance",
+        target_id: instance.id,
+        action: "autosync_completed",
+        status: "success",
+        metadata: {
+          instance_id: instance.id,
+          lock_token: lockToken,
+          duration_ms: Date.now() - perInstanceStartedAt,
+        },
+      });
+    } catch (syncError) {
+      failed += 1;
+
+      const errorMessage =
+        syncError instanceof Error
+          ? syncError.message.slice(0, 500)
+          : "autosync_failed";
+
+      await insertActionLogBestEffort(supabase, {
+        agency_id: instance.agency_id,
+        actor_user_id: null,
+        target_type: "plesk_instance",
+        target_id: instance.id,
+        action: "autosync_failed",
+        status: "failed",
+        error_message: errorMessage,
+        metadata: {
+          instance_id: instance.id,
+          lock_token: lockToken,
+          duration_ms: Date.now() - perInstanceStartedAt,
+          error_summary: errorMessage,
+        },
+      });
+    } finally {
+      const nowIso = new Date().toISOString();
+      const nextAutoSyncAtIso = new Date(
+        Date.now() + frequencyMinutes * 60 * 1000,
+      ).toISOString();
+
+      const { error: scheduleError } = await supabase
+        .from("plesk_instances")
+        .update({
+          last_auto_sync_at: nowIso,
+          next_auto_sync_at: nextAutoSyncAtIso,
+          auto_sync_lock_until: null,
+          auto_sync_lock_token: null,
+        })
+        .eq("id", instance.id)
+        .eq("auto_sync_lock_token", lockToken);
+
+      if (scheduleError) {
+        console.error(
+          "[autosync] schedule update failed",
+          scheduleError.message,
+        );
+      }
+    }
+  }
+
+  const workers = Array.from(
+    { length: Math.min(MAX_CONCURRENCY, queue.length) },
+    async () => {
+      while (queue.length > 0) {
+        const instance = queue.shift();
+        if (!instance) break;
+        await processInstance(instance);
+      }
+    },
+  );
+
+  await Promise.all(workers);
+
+  return {
+    instances_considered: eligible.length,
+    locks_acquired: locksAcquired,
+    succeeded,
+    failed,
+    duration_ms: Date.now() - startedAt,
+  };
+}
diff --git a/lib/types.ts b/lib/types.ts
index a57be4e..db6e9ef 100644
--- a/lib/types.ts
+++ b/lib/types.ts
@@ -83,6 +83,12 @@ export type Database = {
           last_sync_error: string | null;
           last_sync_subscriptions: number;
           last_sync_domains: number;
+          auto_sync_enabled: boolean;
+          auto_sync_frequency_minutes: number;
+          last_auto_sync_at: string | null;
+          next_auto_sync_at: string | null;
+          auto_sync_lock_until: string | null;
+          auto_sync_lock_token: string | null;
           created_at: string;
         };
         Insert: {
@@ -101,6 +107,12 @@ export type Database = {
           last_sync_error?: string | null;
           last_sync_subscriptions?: number;
           last_sync_domains?: number;
+          auto_sync_enabled?: boolean;
+          auto_sync_frequency_minutes?: number;
+          last_auto_sync_at?: string | null;
+          next_auto_sync_at?: string | null;
+          auto_sync_lock_until?: string | null;
+          auto_sync_lock_token?: string | null;
           created_at?: string;
         };
         Update: {
@@ -119,6 +131,12 @@ export type Database = {
           last_sync_error?: string | null;
           last_sync_subscriptions?: number;
           last_sync_domains?: number;
+          auto_sync_enabled?: boolean;
+          auto_sync_frequency_minutes?: number;
+          last_auto_sync_at?: string | null;
+          next_auto_sync_at?: string | null;
+          auto_sync_lock_until?: string | null;
+          auto_sync_lock_token?: string | null;
           created_at?: string;
         };
       };
diff --git a/supabase/migrations/CL6_auto_sync_worker.sql b/supabase/migrations/CL6_auto_sync_worker.sql
new file mode 100644
index 0000000..6465ff8
--- /dev/null
+++ b/supabase/migrations/CL6_auto_sync_worker.sql
@@ -0,0 +1,62 @@
+-- CL6: auto-sync worker scheduling fields + per-instance lock helpers
+
+alter table public.plesk_instances
+  add column if not exists auto_sync_enabled boolean not null default false,
+  add column if not exists auto_sync_frequency_minutes integer not null default 60,
+  add column if not exists last_auto_sync_at timestamptz,
+  add column if not exists next_auto_sync_at timestamptz,
+  add column if not exists auto_sync_lock_until timestamptz,
+  add column if not exists auto_sync_lock_token text;
+
+alter table public.plesk_instances
+  drop constraint if exists plesk_instances_auto_sync_frequency_minutes_check;
+
+alter table public.plesk_instances
+  add constraint plesk_instances_auto_sync_frequency_minutes_check
+  check (auto_sync_frequency_minutes between 5 and 10080);
+
+create index if not exists idx_plesk_instances_auto_sync_due
+  on public.plesk_instances (auto_sync_enabled, next_auto_sync_at);
+
+create or replace function public.acquire_instance_auto_sync_lock(
+  p_instance_id uuid,
+  p_lock_token text,
+  p_ttl_seconds integer default 900
+)
+returns boolean
+language plpgsql
+security definer
+set search_path = public
+as $$
+declare
+  v_acquired boolean := false;
+begin
+  update public.plesk_instances
+  set
+    auto_sync_lock_until = now() + make_interval(secs => p_ttl_seconds),
+    auto_sync_lock_token = p_lock_token
+  where id = p_instance_id
+    and auto_sync_enabled = true
+    and (next_auto_sync_at is null or next_auto_sync_at <= now())
+    and (auto_sync_lock_until is null or auto_sync_lock_until < now());
+
+  get diagnostics v_acquired = row_count;
+  return v_acquired;
+end;
+$$;
+
+create or replace function public.release_instance_auto_sync_lock(
+  p_instance_id uuid,
+  p_lock_token text
+)
+returns void
+language sql
+security definer
+set search_path = public
+as $$
+  update public.plesk_instances
+  set auto_sync_lock_until = null,
+      auto_sync_lock_token = null
+  where id = p_instance_id
+    and auto_sync_lock_token = p_lock_token;
+$$;
\ No newline at end of file