#Oracle kill session query how to
#Oracle kill session query full

In this case, the sort step took 61 microseconds. The TIME element in the output shows how much time the step took. In this case, the output shows that the query retrieved only one row. Right after the tracing statistics in Listing 3, the output lists the row source information, which shows the steps the query executed as well as the statistics for those steps. Because Oracle Database spends some CPU cycles to get a row, the greater the number of rows accessed by the query, the more CPU cycles consumed and the greater the elapsed time.

The QUERY column shows the number of rows retrieved at that stage. The DISK column value in Listing 3 shows 0, meaning that the query got all of its blocks from the buffer cache without needing to go to the physical disk. Now, with the tkprof output from the trace file, you not only know the elapsed time of the individual SQL statements inside the session but also how much of it was spent on CPU.

#Oracle kill session query how to

That same article demonstrated how to measure exactly how much time a session used and how much of it was spent on CPU, but that demonstration didnвЂ™t break down the elapsed times for individual SQL statements in a session. My вЂњ Beginning performance tuningвЂќ article demonstrated that an Oracle Database session is in one of two states: doing something useful (on CPU) or waiting for something such as a latch or a lock. To answer that, notice the number for TOTAL under CPU in Listing 3, which shows the total CPU time. Obviously, your tuning objective is to reduce the elapsed time of the query to reduce the overall time used by the session. Next, look at the total time under ELAPSED. For example, parsing requires CPU cycles, so the greater the CPU number for PARSE, the greater the CPU consumption. Look at the number of calls for each type of operation in Listing 3. The query execution statistics are the first thing you should examine during performance troubleshooting. How many of those queried blocks came from the disk. How many blocks were accessed (queried) by the call (whether from disk or buffer cache). The greater the elapsed time, the more time the session is taking.) The total time of the call, including CPU time. The number of times that type of call has been made. Here are some important table columns in the tkprof output of the trace file and their meanings:

The rest of the output shows execution statistics for the different activities in a table format. The statistics in Listing 3 just after the SQL show the different types of activities called by the query (under CALL): PARSE, EXECUTE, and FETCH.

SALES_MV (cr=3 pr=0 pw=0 time=52 us cost=3

#Oracle kill session query full

Rows (1st) Rows (avg) Rows (max) Row Source OperationДЎ 1 1 SORT AGGREGATE (cr=3 pr=0 pw=0 time=61 us)ДЎ 1 1 MAT_VIEW REWRITE ACCESS FULL CAL_MONTH_ To see tracing concepts and this articleвЂ™s problem and solution in action, first connect to the database as the SH user and run the query shown in Listing 1.Д¬all count cpu elapsed disk query current rows To demonstrate the concepts and the solution, I will use the SH schema, available with the sample schemas of Oracle Database. How can you identify the root cause and resolve the issue? The answer: Trace and analyze the session. Tracing basicsД¬onsider the following problem scenario: Your database application performance has been erratic it has been acting as expected at times and badly at other times. There are many ways you can enable tracing in sessions, but the easiest is to use the Oracle-provided DBMS_MONITOR package. In this article, you will learn how to enable tracing in remote and future sessions and analyze trace files to resolve performance issues. Tracing is the action of enabling a flag in Oracle Database that instructs the database to write the details of the activities inside a session to a text file on the server. To display those details, you need to trace the session. Those tuning techniques do not, however, show the timing of individual queries or the different execution steps in each query. For example, by using those techniques, you can see what events the session has been waiting for, how much time a session has spent on each event, and what resources (CPU cycles, memory, and so on) an event consumed. Want your database to run faster? While common tuning techniques can prove quite helpful in resolving many performance issues, they donвЂ™t show the details of all the activities of a session.