Here’s a common Oracle troubleshooting scenario when a SQL statement needs tuning and/or troubleshooting:
- log on to dev server
- connect to database (on a different server)
- run the SQL statement with 10046 tracing enabled
- ssh to the database server
- copy the trace file back to work environment
- process the trace file.
All of this takes time. Granted, not a great deal of time, but tuning is an iterative process and so these steps will be performed multiple times. Not only are these steps a productivity killer, but they are repetitive and annoying. No one wants to keep running the same manual command over and over.
This task is ripe for some simple automation.
If both the client and database servers are some form of Unix, automating these tasks is straightforward.
Please note that these scripts require an 11g or later version of the Oracle database. These scripts are dependent on the v$diag_info view to retrieve the tracefile name. While these scripts could be made to work on 10g databases, that is left as an exercise for the reader.
Step by Step
To simplify the process it can be broken down into steps.
The first step is to create a new connection each time the SQL is executed. Doing so ensures the database session gets a new tracefile, as we want each execution to be isolated.
— reconnect.sql connect jkstill/[email protected]
2. Get the Tracefile hostname, owner and filename
Oracle provides all the information needed.
In addition the script will set the 10046 event, run the SQL of interest and then disable the 10046 event.
Following is a snippet from the tracefile_identifier_demo.sql script.
— column variables to capture host, owner and tracefile name col tracehost new_value tracehost noprint col traceowner new_value traceowner noprint col tracefile new_value tracefile noprint set term off head off feed off — get oracle owner select username traceowner from v$process where pname = ‘PMON’; — get host name select host_name tracehost from v$instance; — set tracefile identifier alter session set tracefile_identifier = ‘MYTRACEFILE’; select value tracefile from v$diag_info where name = ‘Default Trace File’; set term on head on feed on — do your tracing here alter session set events ‘10046 trace name context forever, level 12’; — run your SQL here @@sql2trace alter session set events ‘10046 trace name context off’;
In this case sql2trace.sql is a simple SELECT from a test table. All of the scripts used here appear in Github as mentioned at the end of this article.
3. Process the Tracefile
Now that the tracefile has been created, it is time to retrieve it.
The following script scp.sql is called from tracefile_identifier_demo.sql.
col scp_src new_value scp_src noprint col scp_target new_value scp_target noprint set term off feed off verify off echo off select ‘&&1’ scp_src from dual; select ‘&&2’ scp_target from dual; set feed on term on verify on –disconnect host scp &&scp_src &&scp_target
Following is an example putting it all together in tracefile_identifier_demo.sql.
SQL> @tracefile_identifier_demo Connected. 1 row selected. PRODUCT VERSION STATUS —————————— ——————– ——————– NLSRTL 188.8.131.52.0 Production Oracle Database 12c Enterprise 184.108.40.206.0 64bit Production Edition PL/SQL 220.127.116.11.0 Production TNS for Linux: 18.104.22.168.0 Production Data Base —————————— P1.JKS.COM INSTANCE_NAME HOST_NAME CURRDATE ——————– —————————— ———————- js122a1 ora12c102rac01.jks.com 2016-05-23 16:38:11 STARTUP ——————– 04/02/2016 11:22:12 Session altered. Elapsed: 00:00:00.00 OWNER OBJECT NAME OBJECT_ID OBJECT_TYPE CREATED ———— —————————— ———- ———————– ——————- SYS OLAP_EXPRESSION 18200 OPERATOR 2016-01-07 21:46:54 SYS OLAP_EXPRESSION_BOOL 18206 OPERATOR 2016-01-07 21:46:54 SYS OLAP_EXPRESSION_DATE 18204 OPERATOR 2016-01-07 21:46:54 SYS OLAP_EXPRESSION_TEXT 18202 OPERATOR 2016-01-07 21:46:54 SYS XMLSEQUENCE 6379 OPERATOR 2016-01-07 21:41:25 SYS XQSEQUENCE 6380 OPERATOR 2016-01-07 21:41:25 SYS XQWINDOWSEQUENCE 6393 OPERATOR 2016-01-07 21:41:25 7 rows selected. Elapsed: 00:00:00.00 Session altered. Elapsed: 00:00:00.00 js122a1_ora_1725_MYTRACEFILE.trc 100% 3014 2.9KB/s 00:00 SQL> host ls -l js122a1_ora_1725_MYTRACEFILE.trc -rw-r—– 1 jkstill dba 3014 May 23 16:38 js122a1_ora_1725_MYTRACEFILE.trc
But Wait, There’s More!
This demo shows you how to automate the retrieval of the trace file. But why stop there? The processing of the file can be modified as well.
Really, it isn’t even necessary to copy the script over, as the content can be retrieved and piped to your favorite command. The script mrskew.sql for instance uses ssh to cat the tracefile, and then pipe the contents to the Method R utility, mrskew. Note: mrskew is a commercial utility, not open source software.
— mrskew.sql col ssh_target new_value ssh_target noprint col scp_filename new_value scp_filename noprint set term off feed off verify off echo off select ‘&&1’ ssh_target from dual; select ‘&&2’ scp_filename from dual; set feed on term on verify on –disconnect host ssh &&ssh_target ‘cat &&scp_filename’ | mrskew
Following is another execution of tracefile_identifier_demo.sql, this time piping output to mrskew. Only the final part of the output is shown following
… Elapsed: 00:00:00.01 CALL-NAME DURATION % CALLS MEAN MIN MAX ————————— ——– —— —– ——– ——– ——– PARSE 0.002000 33.1% 2 0.001000 0.000000 0.002000 db file sequential read 0.001211 20.0% 5 0.000242 0.000056 0.000342 FETCH 0.001000 16.5% 1 0.001000 0.001000 0.001000 gc cr grant 2-way 0.000999 16.5% 1 0.000999 0.000999 0.000999 SQL*Net message from client 0.000817 13.5% 2 0.000409 0.000254 0.000563 Disk file operations I/O 0.000018 0.3% 2 0.000009 0.000002 0.000016 SQL*Net message to client 0.000002 0.0% 2 0.000001 0.000001 0.000001 CLOSE 0.000000 0.0% 2 0.000000 0.000000 0.000000 EXEC 0.000000 0.0% 2 0.000000 0.000000 0.000000 ————————— ——– —— —– ——– ——– ——– TOTAL (9) 0.006047 100.0% 19 0.000318 0.000000 0.002000
Now we can see where all the db time was consumed for this SQL statement, and there was no need to copy the trace file to the current working directory. The same can be done for tkprof and other operations. Please see the plan.sql and tkprof.sql scripts in the Github repository.
Wrapping It Up
A little bit of automation goes a long way. Commands that are repetitive, boring and error prone can easily be automated. Both your productivity and your mood will soar when little steps like these are used to improve your workflow.
All files for this demo can be found at https://github.com/jkstill/tracefile_identifier