LI73181: INSTANCE CAN CRASH IF XQUERY USES POSITION() OR FN:POSITION() WITHOUT THE CONTEXT ITEM DEFINED

DB2 Version 9.1 Fix Pack 7  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 5   for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 6   for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 6a for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 7a  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 8  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 9  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 10  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 11  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 12  for Linux, UNIX and Windows

APAR status

• Closed as fixed if next.

Error description

• Instance can crash if XQuery uses position() or fn:position()
  without the context item defined.  The signal 11 stack trace
  will look something like the following:
  
  0        ossDumpStackTrace
  1        OSSTrapFile::dump
  2        sqlo_trce
  3        sqloEDUCodeTrapHandler
  4        __h_errno_location
  5        sqlnq_qunqncchild::pp
  6        sqlnq_xp_provide_context_sequence
  7        sqlnq_xq_prefix_expression
  8        sqlnq_encap_doit
  9        sqlnq_fun_res_walk
  10       sqlnq_fun_tres
  11       sqlnq_xq_sem
  12       sqlxp_smactn
  13       sqlxp_parser
  14       sqlxp_main
  ............
  49       sqloRunInstance
  50       DB2main
  51       main
  52       __libc_start_main
  53       sqloWaitChild
  

Local fix

• Depending on what the desired output of your query was, you can
  restructure your query using one of the following sample
  queries:
  
  Queries are based on this ddl and data:
  
  create table test ( name char(4), xmldoc xml)
  
  insert into test (name, xmldoc) values( 'aaaa',
  '<doc><more>a1</more><more>a2</more><more>a3</more></doc>'),(
  'bbbb',
  '<doc><more>b1</more><more>b2</more><more>b3</more></doc>')
  
  --Option 1--
  select m.name, t.SAY, t.POS from test m, xmltable('$c/doc/more'
  passing m.xmldoc as "c" columns
  "SAY" varchar(10) path '.', "POS" int path './fn:position()') as
  t where 1 = 1
  
  NAME   SAY   POS
  ---------   ------  -----
  aaaa a1 1
  aaaa a2 1
  aaaa a3 1
  bbbb b1 1
  bbbb b2 1
  bbbb b3 1
  
  --Option 2-
  
  --> use rownumber() over() to retrieve the position
  
  SELECT m.name, xt.* FROM test m, TABLE(SELECT x.*, ROWNUMBER()
  OVER () as POS FROM XMLTABLE('$xml/doc/more' passing m.xmldoc as
  "xml"
  columns "SAY" varchar(10) path '.') as x) as xt WHERE 1=1
  
  NAME SAY POS
  ---- ---------- -----------
  aaaa a1 1
  aaaa a2 2
  aaaa a3 3
  bbbb b1 1
  bbbb b2 2
  bbbb b3 3
  
  --Option 3-
  
  -> the following xquery workaround returns the same output as
  Option 2
  
  select m.name, t.SAY, t.POS from test m, xmltable( 'for $i at $j
  in $c/doc/more
  return <result><pos>{$j}</pos><item>{$i}</item></result>'
  passing m.xmldoc as "c" columns "SAY" varchar(10) path './item',
  "POS" int path './pos') as t where 1 = 1
  
  NAME SAY POS
  ---- --- ---
  aaaa a1 1
  aaaa a2 2
  aaaa a3 3
  bbbb b1 1
  bbbb b2 2
  bbbb b3 3
  

Problem summary

• +
  

Problem conclusion

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

Applicable component levels

• R910 PSY

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