BUG: A SELECT Statement With a Number of SUM(CASE()) Expressions and UNIONs May Cause Stack Overflow (268846)


The information in this article applies to:

  • Microsoft SQL Server 7.0
This article was previously published under Q268846
BUG #: 57937(SQLBUG_70)

SYMPTOMS

A query that contains a number of SUM(CASE()) expressions along with UNION statements in a subquery might result in a stack overflow exception.

The query might fail with the following error message:
Connection Broken
You may also get a message that indicates that the command completed successfully but you might not get the expected results.

CAUSE

The query processor duplicates the list of correlation variables many times and causes the stack overflow.

WORKAROUND

Re-write the query so that it has less UNION statements, or eliminate the UNION statements altogether.

STATUS

Microsoft has confirmed this to be a problem in SQL Server 7.0.

MORE INFORMATION

The SQL Server error log contains an entry similar to the following when the exception error occurs: 
 
2000-05-16 12:05:36.51 spid8    05/16/00 12:05:36 Stack Overflow Dump not possible - Exception c00000fd E at 00477b30
2000-05-16 12:05:36.51 spid8    Address=477b30 Exception Code = c00000fd
2000-05-16 12:05:36.51 spid8    eax=22685574 ebx=00000000 ecx=00000001 edx=00000001
2000-05-16 12:05:36.51 spid8    esi=22685574 edi=21895574 eip=00477b30 esp=2ff33000
2000-05-16 12:05:36.51 spid8    ebp=2ff33008 efl=00010206
2000-05-16 12:05:36.51 spid8    cs=1b ss=23 ds=23 es=23 fs=3b gs=0
2000-05-16 12:05:36.51 spid8    Input Buffer 3882 bytes - 
...<query text>...
2000-05-16 12:05:36.55 spid8    Error: 0, Severity: 19, State: 0
2000-05-16 12:05:36.55 spid8    language_exec: Process 8 generated an access violation. SQL Server is terminating this process.
.
Modification Type:MajorLast Reviewed:10/16/2002
Keywords:kbBug KB268846
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