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Performance Problems with Function Xmltype.toobject (Doc ID 1580474.1)

Last updated on JULY 20, 2021

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.3 to 11.2.0.3 [Release 11.2]
Oracle Database Cloud Schema Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this document applies to any platform.

Symptoms

A complex XML schema is registred into the database as object relational storage, creating an high number of objects types and collection types.

Trying to convert an XML message to a corresponding database object using
XMLTYPE.toObject([message], [schema], [root-element]) the procedure
hangs and never completes.
It uses up a enormous amount of memory and fully loads the CPU: top command
show the oracle process to use more than 90% of CPU.
 
Patch 12940637 has been installed but it does not bring any benefit.

When manually filling up a nested object with test data, we encounter very same behaviour.

The 2 errorstack dump produced at a cetrain time interval shows always the same call stack:


skdstdst ksedst1 ksedst dbkedDefDump ksedmp ksdxfdmp ksdxcb sspuser
sighandler koptgetrealtdslen koptgetrealtdslen pmucpcon pmuocons_construct_segment
pmuocon segment pmuocons_construct_segment pmuocon segment pmuccst pmustcpy_SubTree_Copy
pmustasg_Tree_Assign pmusasc_Assign_Collection pmucasg ection pmucpcpy
pmuocpy2_copy_recur pmuocpy pmuocpy2_copy_recur pmuocpy pmuocpy2_copy_recur
pmuocpy pmuocpy2_copy_recur pmuocpy pmuccpe pmustcpy_SubTree_Copy
pmustasg_Tree_Assign pmusasc_Assign_Collection pmucasg ection pmucpcpy pfritm
pevm_MOVX pfrinstr_MOVX pfrrun_no_tool pfrrun
plsql_run peicnt kkxexe opiexe kpoal8 opiodr ttcpip opitsk opiino opiodr
opidrv sou2o opimai_real ssthrdmain main libc_start_main start




Cause

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In this Document
Symptoms
Cause
Solution
References


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