chore: Update OCORE and OCORE_web submodules to latest commits

- Implemented a new method `ShapeTableNames` to gather entity and navigation table names, ensuring no blanks or duplicates are included.
- Updated `FdsMfrClient` to handle cases where schema queries return no tables, logging appropriate warnings and preventing misleading errors.
- Introduced `PdfPreviewAsync` in `IntranetController` to manage PDF preview rendering, capturing detailed logs for failures and notifying users with readable error messages.
- Added comprehensive unit tests for error logging and table name shaping to ensure robustness and correctness.
- Documented decision to persist user action failures to the `fds__admin_logdebug` table, enhancing support diagnostics.

Fuchs.Tests/ErrorLoggingTests.cs

@@ -0,0 +1,209 @@
+using System;
+using System.Collections.Generic;
+using System.Data;
+using Fuchs.Controllers;
+using Fuchs.intranet;
+using Microsoft.Extensions.Logging;
+using Moq;
+using Newtonsoft.Json;
+using Xunit;
+using static fds.FdsMfrClient;
+
+namespace Fuchs.Tests;
+
+/// <summary>
+/// Covers the error-attribution fixes made after the 2026-09-16 production log review: every
+/// "SQL Error in getSQLDataSet" row in fds__admin_logdebug carried Data=NULL (the failing SQL
+/// was dropped), unhandled Do() exceptions and PDF-preview failures never reached the DB log at
+/// all, and the browser alert always had an empty description. The DB write itself (debug_log →
+/// fds__admin_logdebug) is SQL-bound and not unit-tested; these tests pin what gets handed to it.
+/// </summary>
+public class ErrorLoggingTests
+{
+    // ── FIS_SQLOptions ─────────────────────────────────────────────────────────
+
+    [Fact]
+    public void FisSqlOptions_OnError_ForwardsSqlStatementAndContextToDbLog()
+    {
+        string? codeRef = null; Exception? loggedEx = null; object? loggedData = null;
+        var logger = new Mock<ILogger>();
+        var context = new Dictionary<string, object> { ["fn"] = "inv", ["id"] = "invl", ["code"] = "" };
+        var opt = new FIS_SQLOptions(context, logger.Object, (p, ex, data) => { codeRef = p; loggedEx = ex; loggedData = data; });
+        var ex = new TimeoutException("Das Ausführungstimeout ist abgelaufen.");
+
+        opt.OnError!("getSQLDataSet", ex, new { sql = "EXECUTE [dbo].[fds__getInvoiceList] @authuser;" });
+
+        Assert.Equal("SQL Error in getSQLDataSet", codeRef);
+        Assert.Same(ex, loggedEx);
+        // The DB column is the JSON of this object — it must carry the SQL, which was the missing piece.
+        string json = JsonConvert.SerializeObject(loggedData);
+        Assert.Contains("fds__getInvoiceList", json);
+        Assert.Contains("\"fn\":\"inv\"", json);
+        Assert.Contains("\"id\":\"invl\"", json);
+        logger.Verify(l => l.Log(LogLevel.Error, It.IsAny<EventId>(), It.IsAny<It.IsAnyType>(), ex,
+            It.IsAny<Func<It.IsAnyType, Exception?, string>>()), Times.Once);
+    }
+
+    [Fact]
+    public void FisSqlOptions_OnError_DbLogThrows_DoesNotPropagate()
+    {
+        var opt = new FIS_SQLOptions(null, null, (_, _, _) => throw new InvalidOperationException("no db"));
+
+        var recorded = Record.Exception(() => opt.OnError!("setSQLValue_async", new Exception("x"), new { sql = "SELECT 1;" }));
+
+        Assert.Null(recorded);
+    }
+
+    [Fact]
+    public void FisSqlOptions_BuildLogData_UnwrapsOcoreSqlPayload()
+    {
+        var d = FIS_SQLOptions.BuildLogData(null, new { sql = "SELECT 1;" });
+
+        Assert.Equal("SELECT 1;", d["sql"]);
+        Assert.False(d.ContainsKey("context"));
+    }
+
+    [Fact]
+    public void FisSqlOptions_BuildLogData_KeepsForeignPayloadVerbatim()
+    {
+        var payload = new { statement = "SELECT 2;" };
+
+        var d = FIS_SQLOptions.BuildLogData(null, payload);
+
+        Assert.Same(payload, d["sql"]);
+    }
+
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void FisSqlOptions_BuildLogData_NullOrEmptyContextIsOmitted(bool empty)
+    {
+        var ctx = empty ? new Dictionary<string, object>() : null;
+
+        var d = FIS_SQLOptions.BuildLogData(ctx, new { sql = "SELECT 1;" });
+
+        Assert.False(d.ContainsKey("context"));
+    }
+
+    [Fact]
+    public void FisSqlOptions_BuildLogData_NullData_ProducesEmptyOrContextOnly()
+    {
+        Assert.Empty(FIS_SQLOptions.BuildLogData(null, null));
+        var ctx = new Dictionary<string, object> { ["fn"] = "rem" };
+        var d = FIS_SQLOptions.BuildLogData(ctx, null);
+        Assert.Single(d);
+        Assert.Same(ctx, d["context"]);
+    }
+
+    // ── Do() catch-all + response description header ──────────────────────────
+
+    [Fact]
+    public void BuildDoErrorLogData_ContainsRouteUserAndFormKeys_ButNoFormValues()
+    {
+        var d = IntranetController.BuildDoErrorLogData("rem", "dpreview", "", "user-1", new[] { "token" });
+
+        string json = JsonConvert.SerializeObject(d);
+        Assert.Contains("\"fn\":\"rem\"", json);
+        Assert.Contains("\"id\":\"dpreview\"", json);
+        Assert.Contains("\"user\":\"user-1\"", json);
+        Assert.Contains("\"formKeys\":[\"token\"]", json);
+    }
+
+    [Theory]
+    [InlineData("Die PDF-Vorschau konnte nicht erstellt werden.", "Die%20PDF-Vorschau%20konnte%20nicht%20erstellt%20werden.")]
+    [InlineData("a+b", "a%2Bb")]                       // '+' must not survive: the client maps '+' to a space
+    [InlineData("Zeile1\r\nZeile2", "Zeile1%20%20Zeile2")]
+    [InlineData("  trimmed  ", "trimmed")]
+    public void EncodeResponseDescription_ProducesAsciiHeaderValue_ClientDecodesToOriginal(string msg, string expected)
+    {
+        string encoded = IntranetController.EncodeResponseDescription(msg);
+
+        Assert.Equal(expected, encoded);
+        Assert.All(encoded, c => Assert.True(c < 128, "header must be ASCII"));
+        // Mirror of the client: decodeURIComponent(v.replace(/\+/g, '%20'))
+        Assert.Equal(msg.Replace("\r", " ").Replace("\n", " ").Trim(), Uri.UnescapeDataString(encoded.Replace("+", "%20")));
+    }
+
+    [Fact]
+    public void EncodeResponseDescription_UmlautsSurviveRoundTrip()
+    {
+        const string msg = "Zeitüberschreitung – bitte erneut versuchen";
+        string encoded = IntranetController.EncodeResponseDescription(msg);
+
+        Assert.All(encoded, c => Assert.True(c < 128));
+        Assert.Equal(msg, Uri.UnescapeDataString(encoded));
+    }
+
+    // ── PDF preview failure payloads ──────────────────────────────────────────
+
+    [Fact]
+    public void PdfPreviewFailureMessage_UsesInnermostExceptionText()
+    {
+        var ex = new InvalidOperationException("outer",
+            new AggregateException("agg", new ApplicationException("Font 'Courier New' cannot be resolved")));
+
+        string msg = IntranetController.PdfPreviewFailureMessage(ex);
+
+        Assert.StartsWith("Die PDF-Vorschau konnte nicht erstellt werden: ", msg);
+        Assert.EndsWith("Font 'Courier New' cannot be resolved", msg);
+        Assert.DoesNotContain("outer", msg);
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("   ")]
+    public void PdfPreviewFailureMessage_EmptyExceptionText_FallsBackToGenericText(string text)
+    {
+        string msg = IntranetController.PdfPreviewFailureMessage(new Exception(text));
+
+        Assert.Equal("Die PDF-Vorschau konnte nicht erstellt werden.", msg);
+    }
+
+    [Fact]
+    public void BuildPdfPreviewLogData_CarriesEndpointRefUserAndDuration()
+    {
+        var d = IntranetController.BuildPdfPreviewLogData("rem/dpreview", "tok-123", "user-1", 4321);
+
+        string json = JsonConvert.SerializeObject(d);
+        Assert.Contains("\"what\":\"rem/dpreview\"", json);
+        Assert.Contains("\"ref\":\"tok-123\"", json);
+        Assert.Contains("\"user\":\"user-1\"", json);
+        Assert.Contains("\"ms\":4321", json);
+    }
+
+    // ── Data service: schema failure must not cascade into "FROM [dbo].[]" ────
+
+    private static DataRowCollection NavTables(params string[] names)
+    {
+        var t = new DataTable();
+        t.Columns.Add("tablename", typeof(string));
+        foreach (var n in names) t.Rows.Add(n);
+        return t.Rows;
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("   ")]
+    public void ShapeTableNames_NoEntityTable_ReturnsEmpty_EvenWithNavTables(string entityTable)
+    {
+        var names = DatabaseSchema.ShapeTableNames(entityTable, NavTables("mfr_invoice_items"));
+
+        Assert.Empty(names);
+    }
+
+    [Fact]
+    public void ShapeTableNames_EntityTableFirst_ThenNavTables_SkippingBlanksAndDuplicates()
+    {
+        var names = DatabaseSchema.ShapeTableNames("mfr_invoice", NavTables("mfr_invoice_items", "", "mfr_invoice_items", "mfr_invoice_files"));
+
+        Assert.Equal(new[] { "mfr_invoice", "mfr_invoice_items", "mfr_invoice_files" }, names);
+    }
+
+    [Fact]
+    public void ShapeTableNames_NoNavTables_ReturnsEntityOnly()
+    {
+        var names = DatabaseSchema.ShapeTableNames("mfr_invoice", NavTables());
+
+        Assert.Equal(new[] { "mfr_invoice" }, names);
+    }
+}

Fuchs/Controllers/IntranetController.InvoiceDraft.cs

@@ -75,10 +75,14 @@ public partial class IntranetController
     private async Task<IActionResult> HandleDraftPreview(string fn, string id, string code)
     {
         if (!HasForm("token")) return BadRequest400();
-        var doc = await _invoiceDrafts.RenderPreviewAsync(Form("token"));
+        string token = Form("token");
+        return await PdfPreviewAsync("inv/dpreview", token, async () =>
+        {
+            var doc = await _invoiceDrafts.RenderPreviewAsync(token);
             if (doc == null) return DraftGone();
             var imgcol = await _pdf.DocToImageCollectionAsync(doc);
             return await JSONAsync(new { img = imgcol.ImgB64Array, total = imgcol.TotalPages });
+        });
     }
 
     // POST inv/dsave — { token } → { ok, invid }; flush cache→DB + business event + draftReady

Fuchs/Controllers/IntranetController.Invoices2.cs

@@ -300,9 +300,10 @@ public partial class IntranetController
         }
         _logger.LogDebug("HandleReportDoc found reportid={ReportId} fileName={FileName} mimeType={MimeType} size={Size} user={User}",
             reportid, file.Name, file.MimeType(), content?.Length ?? 0, UserAccountID);
-        return Form("typ") != "img"
+        if (Form("typ") != "img")
-            ? await FileContentResultAsync(content!, file.MimeType(), file.Name)
+            return await FileContentResultAsync(content!, file.MimeType(), file.Name);
-            : await JSONAsync(new { id = reportid, img = await BuildPdfImageArray(content!) });
+        return await PdfPreviewAsync("inv/rdoc", reportid, async () =>
+            await JSONAsync(new { id = reportid, img = await BuildPdfImageArray(content!) }));
     }
 
     private async Task<IActionResult> HandleReportDocByName(string fn, string id, string code)

Fuchs/Controllers/IntranetController.PdfPreview.cs

@@ -0,0 +1,88 @@
+using System.Diagnostics;
+using Fuchs.Observability;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Fuchs.Controllers;
+
+// Partial class: shared guard for every "PDF-Vorschau" endpoint (inv/dpreview, rem/dpreview,
+// req/idoc+img, rem/idoc+img, inv/rdoc+img, rem/rdoc+img).
+//
+// A preview render can fail deep inside MigraDoc / Spire (fonts, licence, malformed HTML in an
+// item text, an oversized inline image, ...). Before this guard such a failure only surfaced as
+// the generic catch-all in Do(): an ErrorLog.txt line on the web server, nothing in the
+// fds__admin_logdebug table support actually reads, and an empty "Der Server hat einen Fehler
+// gemeldet:" alert in the browser. Every preview now goes through PdfPreviewAsync so the failure
+// is (1) written to the DB log with what/id/user/duration, (2) counted, (3) toasted to the user
+// and (4) returned with a readable description header.
+public partial class IntranetController
+{
+    internal const string PdfPreviewLogReference = "PDF preview failed";
+
+    /// <summary>
+    /// Runs <paramref name="render"/> (the endpoint body that produces the preview response) and
+    /// turns any exception into a fully logged, user-readable 500.
+    /// </summary>
+    /// <param name="what">Endpoint tag, e.g. <c>inv/dpreview</c>.</param>
+    /// <param name="refId">Draft token / invoice / reminder / report id the preview is for.</param>
+    private async Task<IActionResult> PdfPreviewAsync(string what, string refId, Func<Task<IActionResult>> render)
+    {
+        var sw = Stopwatch.StartNew();
+        using var act = FuchsTelemetry.StartActivity("pdf.preview");
+        act?.SetTag("fuchs.pdf.preview.what", what);
+        act?.SetTag("fuchs.pdf.preview.ref", refId);
+        _logger.LogDebug("PDF preview {What} ref={RefId} user={User} started", what, refId, UserAccountID);
+        try
+        {
+            var result = await render();
+            sw.Stop();
+            FuchsTelemetry.PdfPreviews.Add(1,
+                new KeyValuePair<string, object?>("what", what),
+                new KeyValuePair<string, object?>("outcome", "success"));
+            _logger.LogInformation("PDF preview {What} ref={RefId} user={User} done in {Ms} ms",
+                what, refId, UserAccountID, sw.ElapsedMilliseconds);
+            return result;
+        }
+        catch (Exception ex)
+        {
+            sw.Stop();
+            act?.SetStatus(ActivityStatusCode.Error, ex.Message);
+            FuchsTelemetry.PdfPreviews.Add(1,
+                new KeyValuePair<string, object?>("what", what),
+                new KeyValuePair<string, object?>("outcome", "failure"));
+            _logger.LogError(ex, "PDF preview {What} ref={RefId} user={User} failed after {Ms} ms",
+                what, refId, UserAccountID, sw.ElapsedMilliseconds);
+            _intranet.debug_log($"{PdfPreviewLogReference} ({what})", ex, UserAccountID,
+                BuildPdfPreviewLogData(what, refId, UserAccountID, sw.ElapsedMilliseconds));
+            await _events.UserIssueAsync(
+                "PDF-Vorschau fehlgeschlagen",
+                "Die PDF-Vorschau konnte nicht erstellt werden. Der Fehler wurde protokolliert.",
+                UserAccountID,
+                new Dictionary<string, object?> { ["what"] = what, ["ref"] = refId });
+            return ServerError(PdfPreviewFailureMessage(ex));
+        }
+    }
+
+    /// <summary>Serialisable payload for the DB log row of a failed preview.</summary>
+    internal static Dictionary<string, object?> BuildPdfPreviewLogData(string what, string refId, string user, long elapsedMs) =>
+        new()
+        {
+            ["what"] = what,
+            ["ref"]  = refId,
+            ["user"] = user,
+            ["ms"]   = elapsedMs
+        };
+
+    /// <summary>
+    /// User-facing message: the innermost exception text is included so the customer can quote
+    /// it to support (this is an internal intranet; the message never carries secrets).
+    /// </summary>
+    internal static string PdfPreviewFailureMessage(Exception ex)
+    {
+        var root = ex;
+        while (root.InnerException != null) root = root.InnerException;
+        string detail = (root.Message ?? "").Trim();
+        return detail.Length == 0
+            ? "Die PDF-Vorschau konnte nicht erstellt werden."
+            : $"Die PDF-Vorschau konnte nicht erstellt werden: {detail}";
+    }
+}

Fuchs/Controllers/IntranetController.Reminder.cs

@@ -89,9 +89,11 @@ public partial class IntranetController
                     _logger.LogWarning("Reminder rdoc: document not found for reminder {RemId} user={User}", Form("id"), UserAccountID);
                     return StatusCode(404, new { error = "Dokument wurde nicht gefunden" });
                 }
-                return Form("typ") != "img"
+                if (Form("typ") != "img")
-                    ? await FileContentResultAsync(fc, file.MimeType(), file.Name)
+                    return await FileContentResultAsync(fc, file.MimeType(), file.Name);
-                    : await JSONAsync(new { id = Form("id"), img = await BuildPdfImageArray(fc) });
+                string remId = Form("id");
+                return await PdfPreviewAsync("rem/rdoc", remId, async () =>
+                    await JSONAsync(new { id = remId, img = await BuildPdfImageArray(fc) }));
             }
 
             case "idoc":   return await HandleReminderIdoc(fn, id, code);
@@ -211,8 +213,11 @@ public partial class IntranetController
                 : _pdf.DocToPdfBytes(_reminders.GenerateReminderPdf(fdRem, fdRem.IsDraft));
             return await FileContentResultAsync(ct, "application/pdf", filename, inline: true);
         }
+        return await PdfPreviewAsync("rem/idoc", fdRem.Id, async () =>
+        {
             var imgcol = await _pdf.DocToImageCollectionAsync(_reminders.GenerateReminderPdf(fdRem, fdRem.IsDraft));
             return await JSONAsync(new { id = fdRem.Id, img = imgcol.ImgB64Array, total = imgcol.TotalPages });
+        });
     }
 
     private async Task<IActionResult> HandleReminderResend(string fn, string id, string code)

Fuchs/Controllers/IntranetController.ReminderDraft.cs

@@ -67,10 +67,14 @@ public partial class IntranetController
     private async Task<IActionResult> HandleReminderDraftPreview(string fn, string id, string code)
     {
         if (!HasForm("token")) return BadRequest400();
-        var doc = _reminderDrafts.RenderPreview(Form("token"));
+        string token = Form("token");
+        return await PdfPreviewAsync("rem/dpreview", token, async () =>
+        {
+            var doc = _reminderDrafts.RenderPreview(token);
             if (doc == null) return DraftGone();
             var imgcol = await _pdf.DocToImageCollectionAsync(doc);
             return await JSONAsync(new { img = imgcol.ImgB64Array, total = imgcol.TotalPages });
+        });
     }
 
     // POST rem/dsave — { token } → { ok, remid }; flush cache→DB + business event + draftReady

Fuchs/Controllers/IntranetController.Requests.cs

@@ -405,8 +405,11 @@ public partial class IntranetController
             SetInlinePdfFilename(filename);
             return File(ct, "application/pdf");
         }
+        return await PdfPreviewAsync("req/idoc", fdInv.Id, async () =>
+        {
             var imgcol = await _pdf.DocToImageCollectionAsync(await _invoices.GenerateInvoicePdfAsync(fdInv, fdInv.IsDraft));
             return await JSONAsync(new { id = fdInv.Id, img = imgcol.ImgB64Array, total = imgcol.TotalPages });
+        });
     }
 
     private async Task<IActionResult> HandleRequestResend(string fn, string id, string code)

Fuchs/Controllers/IntranetController.cs

@@ -123,7 +123,25 @@ public partial class IntranetController : Microsoft.AspNetCore.Mvc.Controller
     // ── Action helpers ────────────────────────────────────────────────────────
     protected IActionResult Unauthorized401()  => StatusCode(401);
     protected IActionResult BadRequest400()    => BadRequest();
-    protected IActionResult ServerError(string msg = "") => StatusCode(500, new { error = msg });
+    /// <summary>
+    /// 500 with the message both in the JSON body and in the <c>x-ocms-desc</c> header, which is
+    /// the only place the frontend's default failure handler (<c>$ocms.failure</c>) reads a
+    /// description from — without it the user only ever saw an empty "Der Server hat einen Fehler
+    /// gemeldet:" alert.
+    /// </summary>
+    protected IActionResult ServerError(string msg = "")
+    {
+        if (!string.IsNullOrEmpty(msg))
+            Response.Headers["x-ocms-desc"] = EncodeResponseDescription(msg);
+        return StatusCode(500, new { error = msg });
+    }
+
+    /// <summary>
+    /// Header-safe (ASCII, percent-encoded) form of a user message; the client decodes it with
+    /// <c>decodeURIComponent</c> after mapping <c>+</c> to a space, so spaces must be <c>%20</c>.
+    /// </summary>
+    internal static string EncodeResponseDescription(string msg) =>
+        Uri.EscapeDataString((msg ?? "").Replace("\r", " ").Replace("\n", " ").Trim());
 
     // ── Index (GET /) ─────────────────────────────────────────────────────────
     [AllowAnonymous]
@@ -189,6 +207,11 @@ public partial class IntranetController : Microsoft.AspNetCore.Mvc.Controller
         {
             _logger.LogError(ex, "Unhandled exception in Do fn={Fn} id={Id} code={Code} user={User}",
                 fn, id, code, UserAccountID);
+            // Also persist to fds__admin_logdebug: the ILogger sink is a file on the web server,
+            // while the DB log is what support actually pulls from the customer's database — an
+            // unhandled handler exception used to be invisible there.
+            _intranet.debug_log($"Unhandled exception in Do {fn}/{id}", ex, UserAccountID,
+                BuildDoErrorLogData(fn, id, code, UserAccountID, RequestFormKeys()));
             // Standing rule: an exception that interrupts a user-initiated action must reach the
             // user as a notification, not only the log. This is the catch-all safety net for any
             // Do_Process_* action that throws without first publishing its own (more specific)
@@ -202,10 +225,26 @@ public partial class IntranetController : Microsoft.AspNetCore.Mvc.Controller
                     UserAccountID,
                     new Dictionary<string, object?> { ["fn"] = fn });
             }
-            return ServerError();
+            return ServerError("Die Aktion konnte aufgrund eines unerwarteten Fehlers nicht abgeschlossen werden.");
         }
     }
 
+    /// <summary>Form field names of the current request (never values — they may carry PII/tokens).</summary>
+    private string[] RequestFormKeys() =>
+        Request.HasFormContentType ? Request.Form.Keys.ToArray() : Array.Empty<string>();
+
+    /// <summary>Serialisable context for the DB log row of an unhandled <see cref="Do"/> exception.</summary>
+    internal static Dictionary<string, object?> BuildDoErrorLogData(
+        string fn, string id, string code, string user, IReadOnlyCollection<string> formKeys) =>
+        new()
+        {
+            ["fn"]       = fn,
+            ["id"]       = id,
+            ["code"]     = code,
+            ["user"]     = user,
+            ["formKeys"] = formKeys
+        };
+
     // ── Auth helper ───────────────────────────────────────────────────────────
     private async Task<IActionResult> HandleAuth(string fn, string id, string code)
     {

Fuchs/Docs/Decisions/0023-user-action-failures-persisted-to-db-log.md

@@ -0,0 +1,64 @@
+---
+status: Accepted
+date: 2026-09-16
+applyTo:
+  - "Fuchs/Controllers/**"
+  - "Fuchs/code/FuchsIntranet.cs"
+  - "Fuchs/js/intranet/**"
+supersededBy: ""
+---
+
+# 0023 — Failures of user actions are persisted to `fds__admin_logdebug`, with the SQL and a readable description
+
+## Context
+Support diagnoses production problems from a query over the `fds__admin_logdebug` table
+(`EXECUTE [dbo].[fds__admin_logdebug]` via `Fuchs_intranet.debug_log`) — not from the
+web server's `logs/ErrorLog.txt` ([0003](0003-structured-diagnostic-logging.md)), which is
+rarely reachable. Reviewing the 2026-09-16 production extract of that table showed three gaps:
+
+- Every "SQL Error in getSQLDataSet" row (twelve execution timeouts in one morning) had
+  `Data = NULL`. `FIS_SQLOptions.OnError` logged its constructor *context* (the fn/id/code,
+  usually `null`) instead of the *data* OCORE hands over (`new { sql = … }`), so nobody could
+  tell which statement timed out.
+- Unhandled exceptions from `IntranetController.Do` went to `ILogger` only. A customer's
+  failing "PDF-Vorschau" left no trace in the table at all.
+- The browser's generic failure alert reads its description from the `x-ocms-desc` response
+  header, which the backend never set — so users always saw an empty
+  "Der Server hat einen Fehler gemeldet:".
+
+## Decision
+- **The DB log row must carry what is needed to attribute the failure.** `FIS_SQLOptions`
+  merges the OCORE payload (the SQL statement) with the caller context into the `Data`
+  column (`{ sql, context }`). New `OnError` hooks must never drop the statement.
+- **Every failure that interrupts a user action is written to `fds__admin_logdebug` too**,
+  in addition to `ILogger` and the notification required by
+  [0003](0003-interrupting-exceptions-notify-the-user.md): the `Do` catch-all writes
+  `Unhandled exception in Do {fn}/{id}` with route, user and the form *field names* (never
+  values — they can carry tokens/PII); the PDF-preview endpoints go through a shared guard
+  (`IntranetController.PdfPreviewAsync`) that logs `PDF preview failed (endpoint)` with
+  ref/user/duration, counts `fuchs.pdf.previews{outcome}` and toasts the user.
+- **A 500 carries its message in the `x-ocms-desc` header** (`ServerError(msg)` →
+  `EncodeResponseDescription`: percent-encoded ASCII, spaces as `%20` because the client
+  maps `+` to space before `decodeURIComponent`). Handlers that return a 500 should pass a
+  user-readable German message; the frontend shows it verbatim.
+- **Preview calls in the frontend never fail silently.** They use a 120 s timeout
+  (`$inv.pdfPreviewTimeout`), one shared error handler (`$inv.pdfPreviewFailed`) and a
+  `complete` handler that unfreezes the editor and reports a timeout — `postXT` returns early
+  on a timeout without calling `error`, so `complete` is the only place it is observable.
+
+## Consequences
+- Support can attribute a SQL timeout to its statement straight from the table; a failing
+  preview is visible as one row with endpoint, reference id, user and duration.
+- `debug_log` is a synchronous DB round-trip and is only used on error paths; it must not be
+  added to hot/success paths (see [0003](0003-structured-diagnostic-logging.md) on the cost
+  of DB logging).
+- `x-ocms-desc` is user-facing: messages must be German, short, and free of secrets. The
+  innermost exception text is acceptable for an internal intranet audience.
+
+## Alternatives considered
+- **Enable `FuchsLoggerProvider.DatabaseLoggingEnabled`** so every `ILogger` error lands in
+  the DB. Rejected: it would write every `LogError` (including expected/handled ones and
+  background-service noise) with a DB round-trip each, and the provider has no access to the
+  request context (user, route) that makes a row actionable.
+- **Return the message only in the JSON body.** The generic client failure path never parses
+  the body of a non-2xx response; the header is the existing contract in `oci_basic.js`.

Fuchs/Observability/FuchsTelemetry.cs

@@ -57,6 +57,9 @@ public static class FuchsTelemetry
     public static readonly Counter<long> InvoiceInlineImageFetches =
         Meter.CreateCounter<long>("fuchs.invoice.inlineimages.fetches", "{fetch}",
             "Invoice-text image fetches for inline PDF rendering (ADR 0018), tagged by outcome.");
+    public static readonly Counter<long> PdfPreviews =
+        Meter.CreateCounter<long>("fuchs.pdf.previews", "{preview}",
+            "PDF preview requests (draft/invoice/reminder/report image previews), tagged by endpoint and outcome.");
 
     // ── Performance histograms (durations in milliseconds) ───────────────────
     public static readonly Histogram<double> PdfRenderDuration =

Fuchs/code/FuchsIntranet.cs

@@ -229,13 +229,42 @@ public class FuchsUserIdentity
 public class FIS_SQLOptions : sqloptions
 {
     public FIS_SQLOptions(Dictionary<string, object>? context = null, ILogger? logger = null)
+        : this(context, logger, dbLog: (procedure, ex, data) => FuchsOcmsIntranet.Instance.debug_log(procedure, ex, data: data))
+    {
+    }
+
+    /// <summary>
+    /// Test seam: <paramref name="dbLog"/> receives what would otherwise go to
+    /// <see cref="Fuchs_intranet.debug_log"/> (code reference, exception, serialisable data).
+    /// </summary>
+    internal FIS_SQLOptions(Dictionary<string, object>? context, ILogger? logger,
+        Action<string, Exception?, object?> dbLog)
     {
         OnError = (procedure, ex, data) =>
         {
-            logger?.LogError(ex, "SQL error in {Procedure}: {Message} — context={@Context}",
+            // OCORE hands the failing statement in `data` (new { sql = ... }); `context` is the
-                procedure, ex.Message, context);
+            // caller's fn/id/code. Both are needed to attribute a timeout in the DB log — logging
-            try { FuchsOcmsIntranet.Instance.debug_log($"SQL Error in {procedure}", ex, data: context); }
+            // only the (usually null) context left every "SQL Error in getSQLDataSet" row without
+            // the SQL that timed out.
+            var logData = BuildLogData(context, data);
+            logger?.LogError(ex, "SQL error in {Procedure}: {Message} — sql={@Sql} context={@Context}",
+                procedure, ex.Message, data, context);
+            try { dbLog($"SQL Error in {procedure}", ex, logData); }
             catch { }
         };
     }
+
+    /// <summary>Merges the OCORE error payload (the SQL) with the caller context into one JSON-able object.</summary>
+    internal static Dictionary<string, object?> BuildLogData(IReadOnlyDictionary<string, object>? context, object? data)
+    {
+        var d = new Dictionary<string, object?>();
+        if (data != null)
+        {
+            // OCORE passes new { sql = "..." }; unwrap so the log column reads as the plain statement.
+            var sqlProp = data.GetType().GetProperty("sql");
+            d["sql"] = sqlProp?.GetValue(data) ?? data;
+        }
+        if (context is { Count: > 0 }) d["context"] = context;
+        return d;
+    }
 }

Fuchs/js/intranet/modules/fis.inv_shared.js

@@ -116,6 +116,29 @@ $inv.eM = (r, re, opt) => {
     }
     return $('#topbar').ocmsmenu(m);  /* empty Array => empty menu */
 };
+/* ── PDF preview failure handling (shared by every image-preview call) ────────
+   A preview render can legitimately take longer than the 30s postXT default (Spire
+   rasterises every page), and postXT swallows a timeout silently — the user would
+   sit in front of a frozen editor with no message. So previews get a longer timeout
+   and one handler that always tells the user something: the server's description
+   header when it sent one (the backend logs the failure and puts the reason there),
+   a timeout hint when the request timed out, the generic text otherwise. */
+$inv.pdfPreviewTimeout = 120;   /* seconds */
+$inv.pdfPreviewFailed = function (jqXHR, textStatus) {
+    if ((jqXHR || {}).internalCode === 11110) { $ocms.login.dlg(); return; }
+    let desc = ((jqXHR || {}).internalText || '').trim();
+    if (desc === '' && textStatus === 'timeout') { desc = $ict.pvto; }
+    if (desc === '' && (jqXHR || {}).status === 410) { desc = $ict.pvgone; }
+    alert(($ict.pvf || $t.f1) + (desc !== '' ? '\n' + desc : ''));
+};
+/* postXT never calls `error` for a timeout (it returns early), so the timeout is only
+   observable from `complete`; this builds the complete handler for a preview call. */
+$inv.pdfPreviewComplete = function (layout) {
+    return (jqXHR, textStatus) => {
+        if (layout) { layout.rC('freeze'); }
+        if (textStatus === 'timeout') { $inv.pdfPreviewFailed(jqXHR, textStatus); }
+    };
+};
 /* ── Backend-authoritative draft editing controller (ADR 0006/0007) ───────────
    The server holds the truth for an invoice draft in an in-memory session; this
    object seeds it, sends single edits as deltas, and renders the totals footer +
@@ -352,7 +375,7 @@ $inv.d = {
         if ($fis.ValidateEmail(email) === false) { if (bool(confirm($ict.ivE + $ict.ivEc), false) === false) { return; } }
         l.aC('freeze');
         $ocms.postXT({
-            url: $ocms.url('inv/dpreview'), data: { token: t }, success: (response) => {
+            url: $ocms.url('inv/dpreview'), data: { token: t }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 l.rC('freeze');
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), total = response.total;
                 if (total > 10) { $$.dc('note warn', c).text($ict.tpe); }
@@ -377,7 +400,7 @@ $inv.d = {
                     },
                     cancel: function (e) { if (confirm($ict.cdI)) { $inv.d.close(); $inv.rReload(); } }
                 });
-            }, error: () => { l.rC('freeze'); alert($ict.eis); }
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete(l)
         });
     },
     /* Zwischenspeichern: flush the cache to the DB (no re-upload); stay in the editor. */
@@ -540,7 +563,7 @@ $inv.rd = {
         if ($fis.ValidateEmail(email) === false) { if (bool(confirm($ict.ivE + $ict.ivEc), false) === false) { return; } }
         l.aC('freeze');
         $ocms.postXT({
-            url: $ocms.url('rem/dpreview'), data: { token: t }, success: (response) => {
+            url: $ocms.url('rem/dpreview'), data: { token: t }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 l.rC('freeze');
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88);
                 $.each(response.img || [], (ii, img) => { $$.dc('pdfp', c).append($$.img(img).css('max-height', (vhr - rpx(6)).toString() + 'px')); });
@@ -563,7 +586,7 @@ $inv.rd = {
                     },
                     cancel: function (e) { if (confirm($ict.cdI)) { $inv.rd.close(); $inv.rReload(); } }
                 });
-            }, error: () => { l.rC('freeze'); alert($t.f1); }
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete(l)
         });
     },
     /* Zwischenspeichern: flush the cache to the DB (no re-upload); stay in the editor. */
@@ -1540,7 +1563,7 @@ $inv.disp = (id, typ) => {
     }
     if (u !== '') {
         $ocms.postXT({
-            url: $ocms.url(u), data: { id: id || '', typ: 'img' }, success: (response) => {
+            url: $ocms.url(u), data: { id: id || '', typ: 'img' }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), invid = response.id;
                 $.each(response.img || [], function (ii, img) {
                     $$.dc('pdfp', c).append($$.img(img).css('max-height', (vhr - rpx(6)).toString() + 'px'));
@@ -1548,13 +1571,13 @@ $inv.disp = (id, typ) => {
                 $ocms.dlg(c, {
                     size: [vhr, Math.round(vw() * 0.88)], zindex_min: 50, form: false, exclusive:false
                 });
-            }
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete()
         });
     }
 };
 $inv.jdbn = function (ev) {
     $ocms.postXT({
-        url: $ocms.url('inv/rdocn'), data: { name: ev.data.id || '', typ: 'img' }, success: (response) => {
+        url: $ocms.url('inv/rdocn'), data: { name: ev.data.id || '', typ: 'img' }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
             let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), invid = response.id;
             $.each(response.img || [], function (ii, img) {
                 $$.dc('pdfp', c).append($$.img(img).css('max-height', (vhr - rpx(6)).toString() + 'px'));
@@ -1562,7 +1585,7 @@ $inv.jdbn = function (ev) {
             $ocms.dlg(c, {
                 size: [vhr, Math.round(vw() * 0.88)], zindex: 50, form: false
             });
-        }
+        }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete()
     });
 };
 $inv.sp13b = () => {

Fuchs/js/intranet/modules/fis.inv_txt_de.js

@@ -38,6 +38,9 @@
     pna: 'Diese Seite ist in der Vorschau nicht verfügbar',
     tpe: 'Die Anzahl von {0} Seiten wird aktuell nicht unterstützt',
     eis: 'Der Rechnungsentwurf konnte nicht gespeichert werden.',
+    pvf: 'Die PDF-Vorschau konnte nicht erstellt werden.',
+    pvto: 'Der Server hat nicht rechtzeitig geantwortet (Zeitüberschreitung). Bitte versuchen Sie es erneut.',
+    pvgone: 'Der Entwurf ist auf dem Server nicht mehr vorhanden (Sitzung abgelaufen). Bitte öffnen Sie den Entwurf erneut.',
     iss: 'Zwischenstand speichern.',
     p13b: 'USt -> §13b',
     setm: 'Set-Preisanzeige',

Fuchs/wwwroot/web/fis.inv.de.js

@@ -162,6 +162,9 @@ let $ict = {
     pna: 'Diese Seite ist in der Vorschau nicht verfügbar',
     tpe: 'Die Anzahl von {0} Seiten wird aktuell nicht unterstützt',
     eis: 'Der Rechnungsentwurf konnte nicht gespeichert werden.',
+    pvf: 'Die PDF-Vorschau konnte nicht erstellt werden.',
+    pvto: 'Der Server hat nicht rechtzeitig geantwortet (Zeitüberschreitung). Bitte versuchen Sie es erneut.',
+    pvgone: 'Der Entwurf ist auf dem Server nicht mehr vorhanden (Sitzung abgelaufen). Bitte öffnen Sie den Entwurf erneut.',
     iss: 'Zwischenstand speichern.',
     p13b: 'USt -> §13b',
     setm: 'Set-Preisanzeige',
@@ -692,6 +695,29 @@ $inv.eM = (r, re, opt) => {
     }
     return $('#topbar').ocmsmenu(m);  /* empty Array => empty menu */
 };
+/* ── PDF preview failure handling (shared by every image-preview call) ────────
+   A preview render can legitimately take longer than the 30s postXT default (Spire
+   rasterises every page), and postXT swallows a timeout silently — the user would
+   sit in front of a frozen editor with no message. So previews get a longer timeout
+   and one handler that always tells the user something: the server's description
+   header when it sent one (the backend logs the failure and puts the reason there),
+   a timeout hint when the request timed out, the generic text otherwise. */
+$inv.pdfPreviewTimeout = 120;   /* seconds */
+$inv.pdfPreviewFailed = function (jqXHR, textStatus) {
+    if ((jqXHR || {}).internalCode === 11110) { $ocms.login.dlg(); return; }
+    let desc = ((jqXHR || {}).internalText || '').trim();
+    if (desc === '' && textStatus === 'timeout') { desc = $ict.pvto; }
+    if (desc === '' && (jqXHR || {}).status === 410) { desc = $ict.pvgone; }
+    alert(($ict.pvf || $t.f1) + (desc !== '' ? '\n' + desc : ''));
+};
+/* postXT never calls `error` for a timeout (it returns early), so the timeout is only
+   observable from `complete`; this builds the complete handler for a preview call. */
+$inv.pdfPreviewComplete = function (layout) {
+    return (jqXHR, textStatus) => {
+        if (layout) { layout.rC('freeze'); }
+        if (textStatus === 'timeout') { $inv.pdfPreviewFailed(jqXHR, textStatus); }
+    };
+};
 /* ── Backend-authoritative draft editing controller (ADR 0006/0007) ───────────
    The server holds the truth for an invoice draft in an in-memory session; this
    object seeds it, sends single edits as deltas, and renders the totals footer +
@@ -928,7 +954,7 @@ $inv.d = {
         if ($fis.ValidateEmail(email) === false) { if (bool(confirm($ict.ivE + $ict.ivEc), false) === false) { return; } }
         l.aC('freeze');
         $ocms.postXT({
-            url: $ocms.url('inv/dpreview'), data: { token: t }, success: (response) => {
+            url: $ocms.url('inv/dpreview'), data: { token: t }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 l.rC('freeze');
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), total = response.total;
                 if (total > 10) { $$.dc('note warn', c).text($ict.tpe); }
@@ -953,7 +979,7 @@ $inv.d = {
                     },
                     cancel: function (e) { if (confirm($ict.cdI)) { $inv.d.close(); $inv.rReload(); } }
                 });
-            }, error: () => { l.rC('freeze'); alert($ict.eis); }
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete(l)
         });
     },
     /* Zwischenspeichern: flush the cache to the DB (no re-upload); stay in the editor. */
@@ -1116,7 +1142,7 @@ $inv.rd = {
         if ($fis.ValidateEmail(email) === false) { if (bool(confirm($ict.ivE + $ict.ivEc), false) === false) { return; } }
         l.aC('freeze');
         $ocms.postXT({
-            url: $ocms.url('rem/dpreview'), data: { token: t }, success: (response) => {
+            url: $ocms.url('rem/dpreview'), data: { token: t }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 l.rC('freeze');
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88);
                 $.each(response.img || [], (ii, img) => { $$.dc('pdfp', c).append($$.img(img).css('max-height', (vhr - rpx(6)).toString() + 'px')); });
@@ -1139,7 +1165,7 @@ $inv.rd = {
                     },
                     cancel: function (e) { if (confirm($ict.cdI)) { $inv.rd.close(); $inv.rReload(); } }
                 });
-            }, error: () => { l.rC('freeze'); alert($t.f1); }
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete(l)
         });
     },
     /* Zwischenspeichern: flush the cache to the DB (no re-upload); stay in the editor. */
@@ -2116,7 +2142,7 @@ $inv.disp = (id, typ) => {
     }
     if (u !== '') {
         $ocms.postXT({
-            url: $ocms.url(u), data: { id: id || '', typ: 'img' }, success: (response) => {
+            url: $ocms.url(u), data: { id: id || '', typ: 'img' }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), invid = response.id;
                 $.each(response.img || [], function (ii, img) {
                     $$.dc('pdfp', c).append($$.img(img).css('max-height', (vhr - rpx(6)).toString() + 'px'));
@@ -2124,13 +2150,13 @@ $inv.disp = (id, typ) => {
                 $ocms.dlg(c, {
                     size: [vhr, Math.round(vw() * 0.88)], zindex_min: 50, form: false, exclusive:false
                 });
-            }
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete()
         });
     }
 };
 $inv.jdbn = function (ev) {
     $ocms.postXT({
-        url: $ocms.url('inv/rdocn'), data: { name: ev.data.id || '', typ: 'img' }, success: (response) => {
+        url: $ocms.url('inv/rdocn'), data: { name: ev.data.id || '', typ: 'img' }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
             let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), invid = response.id;
             $.each(response.img || [], function (ii, img) {
                 $$.dc('pdfp', c).append($$.img(img).css('max-height', (vhr - rpx(6)).toString() + 'px'));
@@ -2138,7 +2164,7 @@ $inv.jdbn = function (ev) {
             $ocms.dlg(c, {
                 size: [vhr, Math.round(vw() * 0.88)], zindex: 50, form: false
             });
-        }
+        }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete()
     });
 };
 $inv.sp13b = () => {

Fuchs/wwwroot/web/fis.req.de.js

@@ -162,6 +162,9 @@ let $ict = {
     pna: 'Diese Seite ist in der Vorschau nicht verfügbar',
     tpe: 'Die Anzahl von {0} Seiten wird aktuell nicht unterstützt',
     eis: 'Der Rechnungsentwurf konnte nicht gespeichert werden.',
+    pvf: 'Die PDF-Vorschau konnte nicht erstellt werden.',
+    pvto: 'Der Server hat nicht rechtzeitig geantwortet (Zeitüberschreitung). Bitte versuchen Sie es erneut.',
+    pvgone: 'Der Entwurf ist auf dem Server nicht mehr vorhanden (Sitzung abgelaufen). Bitte öffnen Sie den Entwurf erneut.',
     iss: 'Zwischenstand speichern.',
     p13b: 'USt -> §13b',
     setm: 'Set-Preisanzeige',
@@ -673,6 +676,29 @@ $inv.eM = (r, re, opt) => {
     }
     return $('#topbar').ocmsmenu(m);  /* empty Array => empty menu */
 };
+/* ── PDF preview failure handling (shared by every image-preview call) ────────
+   A preview render can legitimately take longer than the 30s postXT default (Spire
+   rasterises every page), and postXT swallows a timeout silently — the user would
+   sit in front of a frozen editor with no message. So previews get a longer timeout
+   and one handler that always tells the user something: the server's description
+   header when it sent one (the backend logs the failure and puts the reason there),
+   a timeout hint when the request timed out, the generic text otherwise. */
+$inv.pdfPreviewTimeout = 120;   /* seconds */
+$inv.pdfPreviewFailed = function (jqXHR, textStatus) {
+    if ((jqXHR || {}).internalCode === 11110) { $ocms.login.dlg(); return; }
+    let desc = ((jqXHR || {}).internalText || '').trim();
+    if (desc === '' && textStatus === 'timeout') { desc = $ict.pvto; }
+    if (desc === '' && (jqXHR || {}).status === 410) { desc = $ict.pvgone; }
+    alert(($ict.pvf || $t.f1) + (desc !== '' ? '\n' + desc : ''));
+};
+/* postXT never calls `error` for a timeout (it returns early), so the timeout is only
+   observable from `complete`; this builds the complete handler for a preview call. */
+$inv.pdfPreviewComplete = function (layout) {
+    return (jqXHR, textStatus) => {
+        if (layout) { layout.rC('freeze'); }
+        if (textStatus === 'timeout') { $inv.pdfPreviewFailed(jqXHR, textStatus); }
+    };
+};
 /* ── Backend-authoritative draft editing controller (ADR 0006/0007) ───────────
    The server holds the truth for an invoice draft in an in-memory session; this
    object seeds it, sends single edits as deltas, and renders the totals footer +
@@ -909,7 +935,7 @@ $inv.d = {
         if ($fis.ValidateEmail(email) === false) { if (bool(confirm($ict.ivE + $ict.ivEc), false) === false) { return; } }
         l.aC('freeze');
         $ocms.postXT({
-            url: $ocms.url('inv/dpreview'), data: { token: t }, success: (response) => {
+            url: $ocms.url('inv/dpreview'), data: { token: t }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 l.rC('freeze');
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), total = response.total;
                 if (total > 10) { $$.dc('note warn', c).text($ict.tpe); }
@@ -934,7 +960,7 @@ $inv.d = {
                     },
                     cancel: function (e) { if (confirm($ict.cdI)) { $inv.d.close(); $inv.rReload(); } }
                 });
-            }, error: () => { l.rC('freeze'); alert($ict.eis); }
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete(l)
         });
     },
     /* Zwischenspeichern: flush the cache to the DB (no re-upload); stay in the editor. */
@@ -1097,7 +1123,7 @@ $inv.rd = {
         if ($fis.ValidateEmail(email) === false) { if (bool(confirm($ict.ivE + $ict.ivEc), false) === false) { return; } }
         l.aC('freeze');
         $ocms.postXT({
-            url: $ocms.url('rem/dpreview'), data: { token: t }, success: (response) => {
+            url: $ocms.url('rem/dpreview'), data: { token: t }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 l.rC('freeze');
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88);
                 $.each(response.img || [], (ii, img) => { $$.dc('pdfp', c).append($$.img(img).css('max-height', (vhr - rpx(6)).toString() + 'px')); });
@@ -1120,7 +1146,7 @@ $inv.rd = {
                     },
                     cancel: function (e) { if (confirm($ict.cdI)) { $inv.rd.close(); $inv.rReload(); } }
                 });
-            }, error: () => { l.rC('freeze'); alert($t.f1); }
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete(l)
         });
     },
     /* Zwischenspeichern: flush the cache to the DB (no re-upload); stay in the editor. */
@@ -2097,7 +2123,7 @@ $inv.disp = (id, typ) => {
     }
     if (u !== '') {
         $ocms.postXT({
-            url: $ocms.url(u), data: { id: id || '', typ: 'img' }, success: (response) => {
+            url: $ocms.url(u), data: { id: id || '', typ: 'img' }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
                 let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), invid = response.id;
                 $.each(response.img || [], function (ii, img) {
                     $$.dc('pdfp', c).append($$.img(img).css('max-height', (vhr - rpx(6)).toString() + 'px'));
@@ -2105,13 +2131,13 @@ $inv.disp = (id, typ) => {
                 $ocms.dlg(c, {
                     size: [vhr, Math.round(vw() * 0.88)], zindex_min: 50, form: false, exclusive:false
                 });
-            }
+            }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete()
         });
     }
 };
 $inv.jdbn = function (ev) {
     $ocms.postXT({
-        url: $ocms.url('inv/rdocn'), data: { name: ev.data.id || '', typ: 'img' }, success: (response) => {
+        url: $ocms.url('inv/rdocn'), data: { name: ev.data.id || '', typ: 'img' }, timeout: $inv.pdfPreviewTimeout, success: (response) => {
             let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), invid = response.id;
             $.each(response.img || [], function (ii, img) {
                 $$.dc('pdfp', c).append($$.img(img).css('max-height', (vhr - rpx(6)).toString() + 'px'));
@@ -2119,7 +2145,7 @@ $inv.jdbn = function (ev) {
             $ocms.dlg(c, {
                 size: [vhr, Math.round(vw() * 0.88)], zindex: 50, form: false
             });
-        }
+        }, error: $inv.pdfPreviewFailed, complete: $inv.pdfPreviewComplete()
     });
 };
 $inv.sp13b = () => {

Fuchs_DataService/FdsMfrClient.cs

@@ -92,21 +92,41 @@ public class FdsMfrClient : IDisposable
             foreach (DataRow nprw in dset.Tables("navigation_properties").Rows)
                 NavProperties[nprw.nz("name").ToLower()] = nprw.toStringDictionary();
 
-            var sqlList = new List<string> { NewDatatableSql(EntityTableName) };
+            // When mfr__getSchema itself failed (deadlock victim / timeout) there is no table name
-            var tableNames = new List<string> { EntityTableName };
+            // to build the TOP(0) shape queries from. Running them anyway produced a second, misleading
-            foreach (DataRow ttrw in dset.Tables("tables").Rows)
+            // "FROM [dbo].[]" error per sync and hid the real cause; the caller sees IsValid=false.
+            var shapeTables = ShapeTableNames(EntityTableName, dset.Tables("tables").Rows);
+            if (shapeTables.Length == 0)
             {
-                sqlList.Add(NewDatatableSql(ttrw.nz("tablename")));
+                logger?.LogWarning("DatabaseSchema for {Entity}: schema query returned no entity table (exception={Exception}); skipping table-shape load",
-                tableNames.Add(ttrw.nz("tablename"));
+                    ThisEntityName, dset.Exception);
+                _tableSet = new DataSet();
+                return;
             }
 
             _tableSet = Task.Run(async () => await getSQLDataSet_async(
-                string.Join(Environment.NewLine, sqlList),
+                string.Join(Environment.NewLine, shapeTables.Select(NewDatatableSql)),
                 FdsShared.FDSConnectionString(),
-                tablenames: tableNames.ToArray(),
+                tablenames: shapeTables,
                 options: new FdsSqlOptions(logger: logger))).Result.DataSet;
         }
 
+        /// <summary>
+        /// Entity table plus its navigation tables, without blanks: the list of tables whose
+        /// (empty) shape is loaded. Empty when the entity table itself is unknown.
+        /// </summary>
+        internal static string[] ShapeTableNames(string entityTableName, DataRowCollection navTables)
+        {
+            if (string.IsNullOrWhiteSpace(entityTableName)) return Array.Empty<string>();
+            var names = new List<string> { entityTableName };
+            foreach (DataRow row in navTables)
+            {
+                string tbl = row.nz("tablename");
+                if (!string.IsNullOrWhiteSpace(tbl) && !names.Contains(tbl)) names.Add(tbl);
+            }
+            return names.ToArray();
+        }
+
         public DataSet TgtDataset(string setId)
         {
             var dset = new DataSet();

Fuchs_DataService/Fuchs_DataService.xml

@@ -16,6 +16,12 @@
         <member name="F:fds.FdsMfr.InvoiceFileDownloadConcurrency">
             <summary>Max parallel invoice-file downloads (independent per file).</summary>
         </member>
+        <member name="M:fds.FdsMfrClient.DatabaseSchema.ShapeTableNames(System.String,System.Data.DataRowCollection)">
+            <summary>
+            Entity table plus its navigation tables, without blanks: the list of tables whose
+            (empty) shape is loaded. Empty when the entity table itself is unknown.
+            </summary>
+        </member>
         <member name="T:fds.FdsConfig">
             <summary>
             Holds the application <see cref="T:Microsoft.Extensions.Configuration.IConfiguration"/> supplied by the host (the Fuchs web app).