TEST_Cloud- Cash Market Readiness Newsflash | Xetra Incident Handling Refresher Newsflash

Dear Xetra Participant,

While our constant effort is to keep the usual high availability rate of the T7 trading system for the markets Xetra and Börse Frankfurt/Börse Frankfurt Zertifikate, we want to support our Trading Participants to be prepared as best as possible for the rarely occurring incident cases. Therefore, we publish newsflash messages on a regular basis to explain the handling of various special incident cases or provide more general incident handling information.

Today, we provide you with the information on order book restatement after market reset events.

1.    Background information

Technical problems such as central components failure events (which are very unlikely) may lead to matching engine failover or matching engine failure, which will trigger the market reset event.

In particular, a matching engine failover is not transparent, but always implies a market reset. With a market reset, all non-persistent orders and quotes on the affected partition are deleted.  In case the primary matching engine fails, the secondary component will take over by loading the persistent orders from the persistency layer and trading continues after a market reset. As non-persistent orders were already deleted following the market reset and thus were unknown to the secondary matcher, there will be no notification about a deletion of these.

Please note that some of the actions prior to a failure of the matching engine may have triggered a preliminary acknowledgement to the trading participant, but may not have persisted. It is therefore crucial that the states of all orders are synchronised with the order book restatement after the secondary component takes over. The following lays down the expected sequence of events in this context:

• After a market reset event, all active persistent orders of a session will be transmitted to the market participant via the respective session;
• At first, a Trading Session Event message is sent, informing the participant about a market reset event per partition respectively;
• Optionally followed by Extended Order Information messages for each restated order of the corresponding session and finally, a Trading Session Event message is sent, indicating the end of the restatement per product.

Please note that order book restatement messages (and the Trading Session Event messages mentioned above) are recoverable.

2.    Best Practice

Due to the preliminary nature of all responses (including preliminary Execution Reports), sent by the matching engine, it is crucial to synchronise the state of all persistent orders with the order book restatement, in case a market reset has been issued by the matching engine.

We urge participants to synchronise the states of all their orders with the restatement after a market reset. This is required, as there may have been order additions/modifications/cancellations/executions, acknowledged by the matching engine, which, however, did not reach the persistency layer and thus, are not taken into consideration after a market reset.

Important note: if there is no Trade Notification (over ETI) / Trade Capture Report (over FIX) for a given Execution Report, then, this Execution Report must be considered invalid and should be discarded.

More details about Order Book Restatement can be found in our Enhanced Trading Interface (ETI) Manual, section "4.7.10 Order Book Restatement" and in the T7 FIX Gateway Manual, section "3.9.11 Order Book Restatement".

3.    Focus days in Simulation

This focus day scenario is designed to assist participants in testing the event "Matching Engine Failover and Failure".

Please refer to the section "Matching Engine Failover and Failure" in the Participant Simulation Guide for more details:

Technology > T7 Trading architecture > System documentation > Release 9.0 > Simulation

Simulation Calendar, under the following path:

Trading > Trading calendar and trading hours

The latest news on the development and the implementation of T7 for Xetra, Börse Frankfurt/Börse Frankfurt Zertifikate is available on our Implementation News page:

Technology > Implementation News

4.    Further information

For further information, please have a look into the T7 Incident Handling Guide (Chapter 3.5 and 3.9), under the following path:

Technology > T7 trading architecture > System documentation > Release 9.0 > Production

Enhanced Trading Interface (ETI) Manual under the following path:

Technology > T7 trading architecture > System documentation > Release 9.0 > Trading Interfaces

T7 FIX Gateway Manual under the following path:

Technology > T7 trading architecture > System documentation > Release 9.0 > Trading Interfaces

If you have any questions or comments, please contact Cash Markets Operations via +49-69-211-1 14 00 or send an e-mail to cmmarketcontrol@deutsche-boerse.com.

Kind regards, 

Your Cash Markets Operations Team