# Sequence Number Gap Fill

**URL:** <https://forum.fixtrading.org/t/sequence-number-gap-fill/9573>\
**Category:** General Q&A\
**Tags:** xid\_161030, imported, 41-changes\
**Created:** [August 5, 2008, 5:43pm UTC](https://forum.fixtrading.org/t/sequence-number-gap-fill/9573 "2008-08-05T17:43:14Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![stephenisaac\_x](https://avatars.discourse-cdn.com/v4/letter/s/838e76/32.png) [@stephenisaac\_x](https://forum.fixtrading.org/u/stephenisaac_x)\
**Post date:** [August 5, 2008, 5:43pm UTC](https://forum.fixtrading.org/t/sequence-number-gap-fill/9573/1 "2008-08-05T17:43:14Z")

</div>

Imported from previous forum

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<div class="post-metadata">

**Author:** ![stephenisaac\_x](https://avatars.discourse-cdn.com/v4/letter/s/838e76/32.png) [@stephenisaac\_x](https://forum.fixtrading.org/u/stephenisaac_x)\
**Post date:** [August 5, 2008, 5:43pm UTC](https://forum.fixtrading.org/t/sequence-number-gap-fill/9573/2 "2008-08-05T17:43:14Z")

</div>

Testing against a client got the following scenario whereby a sequence number is used twice by TEST1 - ‘34=5’:

Not 100% of how this should be handled so any help would be much appreciated. Many thanks.

Log Entry : 08:01:34 04 August 2008  
:  
: Logon Tx : 8=FIX.4.1 9=964 35=A 34=3 52=20080804-07:01:34 49=TEST1 56=TEST2 115=TEST11 -------------------------------

## Log Entry : 08:01:34 04 August 2008 : : Logon Rx : 8=FIX.4.1 9=965 35=A 49=TEST2 56=TEST1 34=7

## Log Entry : 08:01:35 04 August 2008 : : [20080804-07:01:35][Rx] : 8=FIX.4.1 9=91 35=1 49=TEST2 56=TEST1 34=8 52=20080804-07:01:38 112=20080804-

## Log Entry : 08:01:36 04 August 2008 : :8=FIX.4.1 9=55 35=2 49=TEST1 56=TEST2 34=4 52=20080804-07:01:36 7=3 16=8 10=159

## Log Entry : 08:01:36 04 August 2008 : : [20080804-07:01:36][Rx] : 8=FIX.4.1 9=983 35=U7 56=TEST1 128=TEST11 34=3

## Log Entry : 08:01:37 04 August 2008 : : [20080804-07:01:37][Rx] : 8=FIX.4.1 9=980 35=U7 56=TEST1 128=TEST11 34=4

Sequence Number 5 used for the first time.

## Log Entry : 08:01:37 04 August 2008 : :8=FIX.4.1 9=55 35=2 49=TEST1 56=TEST2 34=5 52=20080804-07:01:37 7=8 16=3 10=161

## Log Entry : 08:01:38 04 August 2008 : : [20080804-07:01:38][Rx] : 8=FIX.4.1 9=978 35=U7 56=TEST1 128=TEST11 34=5

## Log Entry : 08:01:39 04 August 2008 : : [20080804-07:01:39][Rx] : 8=FIX.4.1 9=990 35=U7 56=TEST1 128=TEST11 34=6

## Log Entry : 08:01:39 04 August 2008 : : [20080804-07:01:39][Rx] : 8=FIX.4.1 9=107 35=4 49=TEST2 56=TEST1 34=7 52=20080804-

TEST2 request a resend of sequence number 3

## Log Entry : 08:01:39 04 August 2008 : : [20080804-07:01:39][Rx] : 8=FIX.4.1 9=78 35=2 49=TEST2 56=TEST1 34=9 52=20080804-

Should this gap fill show 36=5 rather than 36=4???

## Log Entry : 08:01:40 04 August 2008 : :8=FIX.4.1 9=62 35=4 34=3 43=Y 49=TEST1 56=TEST2 52=20080804-07:01:40 36=4 123=Y 10=026

## Log Entry : 08:01:40 04 August 2008 : : [20080804-07:01:40][Rx] : 8=FIX.4.1 9=92 35=1 49=TEST2 56=TEST1 34=10 52=20080804-07:01:43 112=20080804-

Sequence Number 5 used for the second time.

## Log Entry : 08:01:42 04 August 2008 : :8=FIX.4.1 9=68 35=0 49=TEST1 56=TEST2 34=5 52=20080804-07:01:42 112=20080804-07:01:38 10=086

43=5 BEEN USED AGAIN. WHAT SHOULD BE THE SEQUENCE AFTER THE TEST2 RESEND REQUEST?

## Log Entry : 08:01:42 04 August 2008 : : [20080804-07:01:42][Rx] : 8=FIX.4.1 9=118 35=5 49=TEST2 56=TEST1 34=11 52=20080804-07:01:45 58=Sequence error: Received 5 when expecting 6.

* * *

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<div class="post-metadata">

**Author:** ![changpengyu\_x](https://avatars.discourse-cdn.com/v4/letter/c/8edcca/32.png) [@changpengyu\_x](https://forum.fixtrading.org/u/changpengyu_x)\
**Post date:** [August 5, 2008, 9:44pm UTC](https://forum.fixtrading.org/t/sequence-number-gap-fill/9573/3 "2008-08-05T21:44:05Z")

</div>

> Testing against a client got the following scenario whereby a sequence  
> number is used twice by TEST1 - ‘34=5’:
> 
> Not 100% of how this should be handled so any help would be much  
> appreciated. Many thanks.
> 
> Log Entry : 08:01:34 04 August 2008  
> :  
> : Logon Tx : 8=FIX.4.1 9=964 35=A 34=3 52=20080804-07:01:34 49=TEST1  
> : 56=TEST2 115=TEST11 -------------------------------
> 
> ## Log Entry : 08:01:34 04 August 2008 : : Logon Rx : 8=FIX.4.1 9=965 35=A 49=TEST2 56=TEST1 34=7
> 
> ## Log Entry : 08:01:35 04 August 2008 : : [20080804-07:01:35][Rx] : 8=FIX.4.1 9=91 35=1 49=TEST2 56=TEST1 : 34=8 52=20080804-07:01:38 112=20080804-
> 
> ## Log Entry : 08:01:36 04 August 2008 : :8=FIX.4.1 9=55 35=2 49=TEST1 56=TEST2 34=4 52=20080804-07:01:36 7=3 :16=8 10=159
> 
> ## Log Entry : 08:01:36 04 August 2008 : : [20080804-07:01:36][Rx] : 8=FIX.4.1 9=983 35=U7 56=TEST1 : 128=TEST11 34=3
> 
> ## Log Entry : 08:01:37 04 August 2008 : : [20080804-07:01:37][Rx] : 8=FIX.4.1 9=980 35=U7 56=TEST1 : 128=TEST11 34=4
> 
> Sequence Number 5 used for the first time.
> 
> ## Log Entry : 08:01:37 04 August 2008 : :8=FIX.4.1 9=55 35=2 49=TEST1 56=TEST2 34=5 52=20080804-07:01:37 7=8 :16=3 10=161
> 
> ## Log Entry : 08:01:38 04 August 2008 : : [20080804-07:01:38][Rx] : 8=FIX.4.1 9=978 35=U7 56=TEST1 : 128=TEST11 34=5
> 
> ## Log Entry : 08:01:39 04 August 2008 : : [20080804-07:01:39][Rx] : 8=FIX.4.1 9=990 35=U7 56=TEST1 : 128=TEST11 34=6
> 
> ## Log Entry : 08:01:39 04 August 2008 : : [20080804-07:01:39][Rx] : 8=FIX.4.1 9=107 35=4 49=TEST2 56=TEST1 : 34=7 52=20080804-
> 
> TEST2 request a resend of sequence number 3
> 
> ## Log Entry : 08:01:39 04 August 2008 : : [20080804-07:01:39][Rx] : 8=FIX.4.1 9=78 35=2 49=TEST2 56=TEST1 : 34=9 52=20080804-
> 
> Should this gap fill show 36=5 rather than 36=4???
> 
> ## Log Entry : 08:01:40 04 August 2008 : :8=FIX.4.1 9=62 35=4 34=3 43=Y 49=TEST1 56=TEST2 52=20080804-07:01:40 :36=4 123=Y 10=026
> 
> ## Log Entry : 08:01:40 04 August 2008 : : [20080804-07:01:40][Rx] : 8=FIX.4.1 9=92 35=1 49=TEST2 56=TEST1 : 34=10 52=20080804-07:01:43 112=20080804-
> 
> Sequence Number 5 used for the second time.
> 
> ## Log Entry : 08:01:42 04 August 2008 : :8=FIX.4.1 9=68 35=0 49=TEST1 56=TEST2 34=5 52=20080804-07:01:42 112=20080804- :07:01:38 10=086
> 
> 43=5 BEEN USED AGAIN. WHAT SHOULD BE THE SEQUENCE AFTER THE TEST2  
> RESEND REQUEST?
> 
> ## Log Entry : 08:01:42 04 August 2008 : : [20080804-07:01:42][Rx] : 8=FIX.4.1 9=118 35=5 49=TEST2 56=TEST1 : 34=11 52=20080804-07:01:45 58=Sequence error: Received 5 when : expecting 6.
> 
> * * *

Log Entry : 08:01:37 04 August 2008 :  
:8=FIX.4.1 9=55 35=2 49=TEST1 56=TEST2 34=5 52=20080804-07:01:37 7=8 16=3 10=161

This line is not right. Tag(16) is ending sequence number. It will not less than Tag(7) any time.

Good luck,  
peng  
[http://www.eptop.com/FIX/FixExpress.htm](http://www.eptop.com/FIX/FixExpress.htm)