Experiments. Goals. Experimentation Framework. General Goals: Assignments: Face actual system issues Experimentation. 1 week 2/3 experiments Report

Transcription

1 Experiments Goals General Goals: Face actual system issues Experimentation Assignments: 1 week 2/3 experiments Report Experimentation Framework Experiment Configuration exptool C++/OCI - run SQL statements - measure exec. time Explib Library - dbaccess - utilities (parser/shared buf) SQL scripts Configures: - db access - SQL statements Monitoring tools - OS tools Oracle 9i 1

2 Experimentation Tool Setup / Run / TearDown Setup Parse configuration file Run Start NbJobs threads Each thread: Database connection and DB options (isolation level) Batch SQL script or single statement SQL scripts Commit / rollback Measure execution time exptool.txt on Web site SQL Scripts Creating/Dropping Tables init.sql / cleanup.sql Loading Tables (using sqlldr) load.sql (sqlldr control) load.cmd (sqlldr + command file arguments) Index creation index.sql Transactions runx.sql SQL Scripts (Transactions) Batch Script N SQL statements per file Each statement executed as a transaction NbJobs threads get SQL statements from shared buffer. Single Statement Scripts 1 SQL statement per file. SQL statements may contain parameters ( where number =?) Exptool generates random parameter value All SQL statements executed within one transaction NbJobs threads execute these transaction NbReps times. 2

3 Experiment Configuration Command line -i ConfigFileDirectoryPath c ConfigFileName Config File DB configuration Instance name, user name, password Trace Isolation level Sleep (in between statements) SQL Scripts description Parser is VERY unforgiving Take example config file and modify it Monitoring Tools OS performance monitoring tools: CPU load (top on linux) Disk activity (iostat on linux) Database specific tools Query Plan Explainers Performance monitors Event/Trace monitors Oracle 9i Log on as oracle Create a database Use dbca (database configuration assistant) Create Database General Purpose Instance name given in assignment Initialization parameters Turn off Persistent Initialization Parameters undo_logmanager = MANUAL Include all parameters Redo logs: Large size On a separate disk 3

4 Oracle 9i Stop/Start database server Configure /etc/oratab Dbstart / dbshut command Access the database using sqlplus Setup your environment (ORACLE_SID) Create a new user Create user exper identified by thebest1 Grant dba to user Oracle9i Configure the database oemapp dbastudio Connect as exper/thebest1 Create a large rollback segment (10Mb initial size/1mb increment/unlimited size) in the undotbs tablespace Modify log file location You can t change a log file location: create new log files and delete existing ones. There must always be two log files. Switch active log file in order to delete existing log files Example: log file location Study the influence of log placement on throughput Five variants for experiment (5 config files) Insertions N commands one large transaction Modify exptool Insertions N commands N transactions Updates N commands one large transaction Modify exptool Updates N commands N transactions Updates 1 command 4

5 Example: log file location Set up Log on same disk as data and rollback segment Log on different disk as data and rollback segment Disks with different speeds: Log on fast disk, log on slow disk Measurements Run exptool with different config file / setup Plot throughput (nbstatement/resp.time) for each config file/set up. Report Results Graph for each experiment Explanations Log Log of experimentations: Problem faced, approach, solution found. Recommandations Diary is essential Don t make things up Be fair and square in what you observe Try and explain what you observe Formulate hypothesis Try and confirm/infirm those hypotheses Statistical relevance N variables (1 at a time, all at a time) 5

6 Recommandations Running Experiments is time consuming! 1 day for db creation 1 day per experiment Count on doing it all again when you write up report and realize that you can t really explain what went on. 6