knowledge(performance): add job queue reliability guidance

community/knowledge/performance/job-queue-external-effects-must-be-idempotent.bad.al

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+table 50112 "Queued Export Bad"
+{
+    DataClassification = CustomerContent;
+
+    fields
+    {
+        field(1; "Entry No."; Integer)
+        {
+            AutoIncrement = true;
+        }
+        field(2; Payload; Text[250])
+        {
+        }
+    }
+
+    keys
+    {
+        key(PK; "Entry No.")
+        {
+            Clustered = true;
+        }
+    }
+}
+
+codeunit 50112 "Queued Export Worker Bad"
+{
+    TableNo = "Job Queue Entry";
+
+    trigger OnRun()
+    var
+        QueuedExport: Record "Queued Export Bad";
+        Client: HttpClient;
+        Content: HttpContent;
+        Response: HttpResponseMessage;
+    begin
+        if not QueuedExport.FindFirst() then
+            exit;
+
+        Content.WriteFrom(QueuedExport.Payload);
+        Client.Post('https://example.local/exports', Content, Response);
+        if not Response.IsSuccessStatusCode() then
+            Error('Export failed with HTTP status %1.', Response.HttpStatusCode());
+
+        // If this local step fails, the external export exists but this row is retried.
+        UpdateLocalStatus();
+        FinalizeExport(QueuedExport);
+    end;
+
+    local procedure UpdateLocalStatus()
+    begin
+    end;
+
+    local procedure FinalizeExport(var QueuedExport: Record "Queued Export Bad")
+    begin
+        QueuedExport.Delete();
+    end;
+}