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TITLE: Enabling SQL Server Trace-Flags without a Service Restart
CANONICAL URI: https://www.totalsql.com/sql-server-content/kb/enabling-sql-server-trace-flags-without-a-service-restart
AUTHOR: Michael K. Campbell 
COPYRIGHT: 2026 All Rights Reserved: OverAchiever Productions, LLC. 
RELEASED: 2026-10-20
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# Enabling SQL Server Trace-Flags without a Service Restart

:::TOC

## Contents
- [Overview + Trace-Flags Warning](#overview)
- [Enabling Trace-Flags - via Startup Parameters](#enabling-trace-flags---via-startup-parameters)
- [Enabling Trace-Flags via DBCC TRACEON()](#enabling-trace-flags-via-dbcc-traceon)
- [Enabling Trace-Flags without a Restart](#enabling-trace-flags-without-a-restart)

:::

## Overview
- Nothing advanced or tricky. 
- Just an overview of how ONE way of enabling Trace Flags (as startup parameters) does ONE thing, and how another way of enabling Trace Flags (`DBCC TRACEON()`) does the exact opposite. 
- Explained with STEP-BY-STEP instructions for each approach. 
- And a simple outline of how to use BOTH as a means of FULLY enabling Trace Flags "right now" without needing to incur an immediate SQL Server Service Restart. 

::: DANGER

SQL Server Trace Flags, **BY DESIGN**, change the behavior of your SQL Server Engine. Unless you know what you're doing, and/or have been directed by someone who does know what they're doing (and even then), be VERY careful with Trace Flags in any production environment.

::: 

## Enabling Trace-Flags - via Startup Parameters
Enabling SQL Server Trace Flags via Startup Parameters is simple. 

- **Start** > **Microsoft SQL Server ####** > **SQL Server #### Configuration Manager**:

- Then, in the **SQL Server Configuration Manager**, find your SQL Server Service, right-click > **Properties**: 

![Launch SQL Server Configuration Manager](https://assets.overachiever.net/ts/kb/trace_flags_1.png)

- Click on the **Startup Parameters** tab within **Properties**. Then punch in the ID of the Trace-Flag that you want to add - in the format of `-T####` - i.e., I'm adding Trace Flag `4696` in the screenshot below - so `-T4696`.  

![Adding Trace Flags as a Startup Parameter](https://assets.overachiever.net/ts/kb/trace_flags_2.png)

::: WARNING

If it helps, think of adding each trace flag as a 'switch' being sent into a .exe at startup - e.g., `sqlsrv.exe -T1234 -T7890` and so on - because that's EXACTLY what these switches are. Get them and/or the "syntax" wrong and your SQL Server won't be able to start. Period. 

:::

- Once you've specified the flag you wish to add, push the **Add** button, and then click on **OK**. 
- Upon clicking **OK**, you'll see a warning similar to the following - which explains that your change HAS been saved, but won't take effect until you RESTART your SQL Server Service. 

![Changes saved, but won't take effect until SQL Server Restart (warning).](https://assets.overachiever.net/ts/kb/trace_flags_3.png)

- At this point, **if you're OK taking an outage for a restart of your SQL Server Service** (or were already going to restart/reboot anyhow), feel free to restart your SQL Server Service or reboot. 

## Enabling Trace-Flags via DBCC TRACEON()
If you don't want to restart your SQL Server Service "right now" - or whenever you want/NEED to add a Trace Flag into your system, you can always add one temporarily - at a global level - via DBCC TRACEON() - like so: 

```sql

DBCC TRACEON(4696, -1); 

```

The above adds the Trace Flag in question **AS IF** it were a startup parameter - i.e., it becomes global in scope (by default everyone and everything has this TF turned on). 

However, whenever your SQL Server Service restarts, any trace flags that were enabled (or disabled) via `DBCC TRACEON()` "go out of scope" - i.e., TFs applied by `DBCC TRACEON()` only apply until the next time your SQL Server Reboots. 

::: TIP

You can query current trace statuses via `DBCC TRACESTATUS()` - where `DBCC TRACESTATUS(-1);` queries global statuses.

:::

## Enabling Trace-Flags without a Restart
Given that: 
- Adding Trace Flags as Startup Parameters does NOT require a SQL Server Restart "right now", but ONLY applies your changes AFTER a Restart, 
- And that `DBCC TRACEON()` enables a Trace Flag UNTIL the next restart... 

You can easily apply a Trace Flag "right here, and RIGHT NOW" without a reboot - and ensure that the Trace Flag remains in place AFTER a reboot. 

Nothing secret or mysterious. 
Just 
1. Add the Trace Flag as a Startup Parameter. 
2. Triple Check that you defined it correctly - i.e., `-Txxxx`; 
3. Don't restart SQL Server "right now". 
4. Use `DBCC TRACEON (xxxx, -1)` to apply the Trace Flag - server wide - right now. 
5. The next time your SQL Server restarts (normal patching/maintenance window, etc), the change you made via `DBCC TRACEON()` goes OUT of scope (at shutdown), and the **startup parameter** comes INTO scope (at startup).