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Bug 5105397 : DB TIME IS NOT EQUAL TO SUM OF ITS CHILD STATS IN V$SYS_TIME_MODEL

Oracle 作者:rongshiyuan 时间:2014-04-08 15:49:43 0 删除 编辑
Bug 5105397 : DB TIME IS NOT EQUAL TO SUM OF ITS CHILD STATS IN V$SYS_TIME_MODEL

Bug Attributes

 

Type D - Documentation Fixed in Product Version 11.1
Severity 3 - Minimal Loss of Service Product Version 10.2.0.1.0
Status 99 - Closed, Documentation Bug Fixed Platform 233 - Microsoft Windows x64 (64-bit)
Created Mar 20, 2006 Platform Version
Updated Apr 18, 2006 Base Bug N/A
Database Version 10.2.0.1.0 Affects Platforms Port-Specific
Product Source Oracle
 

Related Products

 

Line Oracle Database Products Family Oracle Database Suite
Area Oracle Database Product 5 - Oracle Database - Enterprise Edition
Hdr: 5105397 10.2.0.1.0 RDBMS 10.2.0.1.0 PRODID-5 PORTID-233 Abstract: DB TIME IS NOT EQUAL TO SUM OF ITS CHILD STATS IN  V$SYS_TIME_MODEL   *** 03/20/06 08:09 am *** TAR: ---- 5195855.992   PROBLEM: -------- This is a Documentation Bug logged for 10gR2 Oracle Database Reference Oracle? Database Reference 10g Release 2 (10.2) Part Number B14237-01   The relationships between the statistics listed in Table 7-4   10gR2 Oracle Database Reference(7-48) says the "db time" value is equal to  sum of item(1) ~ item (11), but actally the sum of all other statistics are  greater than "db time" as you can see in the following result.         STAT_NAME                                                           SECONDS ---------------------------------------------------------------- ---------- DB time                                                              620571 DB CPU                                                               230091 background elapsed time                                               16072 background cpu time                                                    2050 sequence load elapsed time                                               29 parse time elapsed                                                    32564 hard parse elapsed time                                               30744 sql execute elapsed time                                             612132 connection management call elapsed time                                 138 failed parse elapsed time                                             21348 failed parse (out of shared memory) elapsed time                          0 hard parse (sharing criteria) elapsed time                              198 hard parse (bind mismatch) elapsed time                                   9 PL/SQL execution elapsed time                                          4544 inbound PL/SQL rpc elapsed time                                           0 PL/SQL compilation elapsed time                                         155   For example the sum of DB CPU and sql execute elapsed time is more  than DB TIME.   The summary is not 100% correct as some statistic times actually are  overlapping. For instance the 'sql execute elapsed time' overlaps with the  'DB CPU' time, as the SQL elapsed time is SQL CPU Time + SQL wait time.   I think it is necessary to update the next release documentation on this, to inform users there is an overlap.   DIAGNOSTIC ANALYSIS: -------------------- The information specified in the 10g official documentation means only that the child times are included into the Parent time, but not that the sum of the child times will be less or equal to their Parent.      "DB time stat" is calculated in 100ths of a second after each database call is completed. However, some other statistics are also calculated for the same call. As they are individual statistics, the summary is not 100% correct as some statistic times actually are overlapping. For instance the 'sql execute elapsed time' overlaps with the 'DB CPU' time, as the SQL elapsed time is SQL CPU Time + SQL wait time.      So although the DB time is the parent of all childs given in the documentation, comparison between SUM of child Times and DB Time isn't accurate at the end.   WORKAROUND: ----------- n/a   RELATED BUGS: -------------   REPRODUCIBILITY: ----------------   TEST CASE: ----------   STACK TRACE: ------------   SUPPORTING INFORMATION: -----------------------   24 HOUR CONTACT INFORMATION FOR P1 BUGS: ----------------------------------------   DIAL-IN INFORMATION: --------------------   IMPACT DATE: ------------   *** 03/20/06 08:09 am *** (CHG: Sta->16) *** 03/20/06 08:21 am *** (CHG: Sta->13 Asg->RDBMSDOC) *** 03/20/06 02:22 pm ***  *** 04/18/06 08:11 am ***  *** 04/18/06 08:11 am ***  *** 04/18/06 08:11 am *** (CHG: Sta->99) *** 04/18/06 08:11 am *** To clarify this description, the following information has been added about  how to interpret the stats in Table 7-4:   The relationship between a parent and a child in the tree  indicates containment only. Please keep the following in mind with regard to the tree:   Children do not necesarilly add up to the parent.   Children are not necessarily exclusive (that is, it is possible that they  overlap)   The union of children does not necessarily cover the whole of the parent.   This information will appear in the next posted review copy. 

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