The document provides guidance on diagnostics and troubleshooting for SAP ASE, including basic traces and commands, ISQL parameters, and methods to identify missing statistics. It covers the lava operator tree for evaluating estimates versus actual values, showplan output details, and final plan costs and elapsed times from query executions. It also includes contact information for further questions or comments.

1. Use this title slide only with an image
Basic Outputs to Troubleshooting Queries.
ASE Customer Coffee Corner
November, 2016

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Customer
Agenda
1. Basic traces and commands for diagnostics.
2. Isql parameters.
3. Get familiar with the query.
4. Missing Statistics.
5. Lava Operator Tree or trace 9526.
6. Showplan output.
7. Final plan cost and Elapsed time.
8. Set statistics i/o.
9. Demo .
10. Questions .

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Customer
Basic traces and commands for diagnostics.
select @@version // Really important to know the version
select @@optlevel // be sure to be in the latest fix level ase_current
select @@optgoal // The goal been used
set statement_cache off // Will generate a new plan avoid using a cached plan
set option show_missing_stats on // Will show missing statistics
set option show brief // Shows basic diagnostics and fixes and criterias enabled
set option show_abstract_plan on // Generates Abstract Plan can be used to test other
plans
set statistics io on // io outputs

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Customer
Cont … Basic traces and commands for diagnostics.
set statistics time on // time output
set statistics plancost on // cost plan
set plan optlevel ase_current // Set current fix level
set showplan on // showplan output
dbcc traceon(3604) // Enable printing diagnostics
dbcc traceon(9526) // Lava Tree ( estimates vs actual values for rows, lios and pios )
dbcc traceflags //Display current trace flags

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Customer
Cont … Basic traces and commands for diagnostics.
set nodata on //omits data set results
<query>
dbcc traceoff(3604,9526)
go

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Customer
Isql parameters.
–U<user> // user to execute the query
-P<password> // password of the user
-w2000 // width of the output to avoid word wrapping
-e // copy commands to the output file
-S<server name> // name of the server to be used
-i <input file> // file to execute
-o <output file> // file to collect diagnostics and traces

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Customer
.
Get familiar with the query.
Take a look at the query.
Draw a graphical representation of it .
Tables.
Indexes.
Columns.

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Customer
Missing Statistics.
Look for missing statistics messages “NO STATS on column” easiest way is using “grep”
command
grep "NO STATS on column" <Diagnostics File>
NO STATS on column #TMP_SHIPMENT.SHPMNT_ID
NO STATS on column SHIPMENT_DTL.SHPMNT_DTL_ID
NO STATS on column SHIPMENT_DTL.SHPMNT_ID
NO STATS on column SHPMNT_DTL_BARCD_X_REF.SHPMNT_DTL_ID

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Customer
Lava Operator Tree or trace 9526.
Lava Operator Tree or trace 9526 output is very important.
Shows both estimates and actual values for rows, Lios and Pios.
Large differences between “act” and “est” usually are signs for inaccurate or lack of statistics.
As shown below each node shows its individual values.

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Customer
Cont .. Lava Operator Tree or trace 9526.
====================== Lava Operator Tree ====================
|Emit (VA = 20, LSTATE_CLOSED)
| Rows: act:362 est:9.808e+06
| |Sequencer (VA = 19, LSTATE_CLOSED)
| | Rows: act:362 est:0
| | |StoreIndex (VA = 2, LSTATE_CLOSED)
| | | Rows: act:87 est:100
| | | Lios: act:11 est:6
| | | Pios: act:2 est:0
| | | cpu: 100 bufct: 24

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Customer
Showplan output.
STEP 1
The type of query is SELECT.
20 operator(s) under root
|ROOT:EMIT Operator (VA = 20)
|
| |SEQUENCER Operator (VA = 19) has 2 children.
| |
| | |STORE Operator (VA = 2)
| | | Worktable1 created, in allpages locking mode, for REFORMATTING.
| | | Creating clustered index.
| | |
| | | |INSERT Operator (VA = 1)
| | | | The update mode is direct.
| | | |
| | | | |SCAN Operator (VA = 0)
| | | | | FROM TABLE
| | | | | #TMP_SHIPMENT
| | | | | T
| | | | | Table Scan.
| | | | | Forward Scan.
| | | | | Positioning at start of table.
| | | | | Using I/O Size 2 Kbytes for data pages.
| | | | | With LRU Buffer Replacement Strategy for data pages.
| | | |
| | | | TO TABLE
| | | | Worktable1.

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Customer
Final plan cost and Elapsed time.
FINAL PLAN ( total cost = 2.317187e+08 ):
lio=8516448 pio=8516444 cpu=1.774662e+07 tempdb=6228.525
Adaptive Server cpu time: 3000 ms.
Adaptive Server elapsed time: 4886 ms.

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Customer
Set statistics i/o.
Table: SHPMNT_DTL_BARCD_X_REF (X) scan count 1690,
logical reads: (regular=3454 apf=0 total=3454),
physical reads: (regular=0 apf=0 total=0), apf IOs used=0
Table: SHIPMENT_DTL (D) scan count 1735,
logical reads: (regular=4724 apf=0 total=4724),
physical reads: (regular=0 apf=0 total=0), apf IOs used=0

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Customer
Document Links
Documentation:
SAP® Adaptive Server® Enterprise Performance and Tuning Series

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Thank you
Feel free to email questions, ideas, or comments to:
sap-psglobalaseccc@sap.com