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The CHECK LOB OptionThe CHECK LOB utility is used to verify the accuracy and integrity of data in auxiliary table spaces for LOB columns . It can be used to detect structural defects in the LOB table space and invalid LOB values. After successfully running CHECK LOB , all CHECK PENDING (CHKP) and auxiliary warning ( AUXW ) statuses will be reset. If exceptions are encountered , CHECK LOB will report on those exceptions only. CHECK LOB cannot be used to fix the exceptions it finds. The JCL in Listing 31.3 can be used to check data in a DB2 sample auxiliary table that contains LOB columns. Listing 31.3. CHECK LOB JCL//DB2JOBU JOB (UTILITY),'DB2 CHECK LOB',MSGCLASS=X,CLASS=X, // NOTIFY=USER //* //**************************************************************** //* //* DB2 CHECK LOB UTILITY //* //**************************************************************** //* //UTIL EXEC DSNUPROC,SYSTEM=DSN,UID='CHECKLOB',UTPROC=" //* //* UTILITY WORK DATASETS //* //DSNUPROC.SORTWK01 DD UNIT=SYSDA,SPACE=(CYL,(5,1)) //DSNUPROC.SORTWK02 DD UNIT=SYSDA,SPACE=(CYL,(5,1)) //DSNUPROC.SORTOUT DD DSN=&&SORTOUT, // UNIT=SYSDA,SPACE=(CYL,(5,1)) //DSNUPROC.SYSERR DD DSN=&&SYSERR, // UNIT=SYSDA,SPACE=(CYL,(1,1)) //DSNUPROC.SYSUT1 DD DSN=&&SYSUT1, // UNIT=SYSDA,SPACE=(CYL,(5,1)) //DSNUPROC.UTPRINT DD SYSOUT=X //DSNUPROC.SYSIN DD * CHECK LOB TABLESPACE DSN8D81L.DSN8S81M EXCEPTIONS 0 /* // CHECK LOB PhasesThe five phases of the CHECK LOB utility are:
CHECK LOB Locking ConsiderationsAny operation or other online utility that attempts to update the same LOB table space cannot be run at the same time as CHECK LOB . CHECK LOB will drain write claim classes for both the LOB table space and the auxiliary table index being processed . The EXCEPTIONS ParameterThe EXCEPTIONS parameter is used to specify the maximum number of exceptions, which are reported by messages only. If the maximum number of exceptions is exceeded, CHECK LOB will terminate in the CHECKLOB phase. Specifying EXCEPTIONS 0 indicates that no limit is to be applied to the number of exceptions. NOTE If the EXCEPTIONS parameter is not specified, CHECK LOB will use EXCEPTIONS 0 as the default. |
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