pgbench README 2002/07/20 Tatsuo Ishii (t-ishii@sra.co.jp) o What is pgbench? pgbench is a simple program to run a benchmark test sort of "TPC-B". pgbench is a client application of PostgreSQL and runs with PostgreSQL only. It performs lots of small and simple transactions including select/update/insert operations then calculates number of transactions successfully completed within a second (transactions per second, tps). Targeting data includes a table with at least 100k tuples. Example outputs from pgbench look like: number of clients: 4 number of transactions per client: 100 number of processed transactions: 400/400 tps = 19.875015(including connections establishing) tps = 20.098827(excluding connections establishing) Similar program called "JDBCBench" already exists, but it requires Java that may not be available on every platform. Moreover some people concerned about the overhead of Java that might lead inaccurate results. So I decided to write in pure C, and named it "pgbench." o features of pgbench - pgbench is written in C using libpq only. So it is very portable and easy to install. - pgbench can simulate concurrent connections using asynchronous capability of libpq. No threading is required. o How to install pgbench (1) Configure and build the standard Postgres distribution. You can get away with just running configure at the top level and doing "make all" in src/interfaces/libpq. (2) Run make in this directory. You will see an executable file "pgbench". You can run it here, or install it with the standard Postgres programs by doing "make install". o How to use pgbench? (1) Initialize database by: pgbench -i where is the name of database. pgbench uses four tables accounts, branches, history and tellers. These tables will be destroyed. Be very careful if you have tables having same names. Default test data contains: table # of tuples ------------------------- branches 1 tellers 10 accounts 100000 history 0 You can increase the number of tuples by using -s option. See below. (2) Run the benchmark test pgbench The default configuration is: number of clients: 1 number of transactions per client: 10 o options pgbench has number of options. -h hostname hostname where the backend is running. If this option is omitted, pgbench will connect to the localhost via Unix domain socket. -p port the port number that the backend is accepting. default is libpq's default, usually 5432. -c number_of_clients Number of clients simulated. default is 1. -t number_of_transactions Number of transactions each client runs. default is 10. -s scaling_factor this should be used with -i (initialize) option. number of tuples generated will be multiple of the scaling factor. For example, -s 100 will imply 10M (10,000,000) tuples in the accounts table. default is 1. NOTE: scaling factor should be at least as large as the largest number of clients you intend to test; else you'll mostly be measuring update contention. -U login Specify db user's login name if it is different from the Unix login name. -P password Specify the db password. CAUTION: using this option might be a security hole since ps command will show the password. Use this for TESTING PURPOSE ONLY. -n No vacuuming and cleaning the history table prior to the test is performed. -v Do vacuuming before testing. This will take some time. With neither -n nor -v, pgbench will vacuum tellers and branches tables only. -S Perform select only transactions instead of TPC-B. -C Establish connection for each transaction, rather than doing it just once at beginning of pgbench in the normal mode. This is useful to measure the connection overhead. -l Write the time taken by each transaction to a logfile, with the name "pgbench_log.xxx", where xxx is the PID of the pgbench process. The format of the log is: client_id transaction_no time where time is measured in microseconds. -d debug option. o What is the "transaction" actually performed in pgbench? (1) begin; (2) update accounts set abalance = abalance + :delta where aid = :aid; (3) select abalance from accounts where aid = :aid; (4) update tellers set tbalance = tbalance + :delta where tid = :tid; (5) update branches set bbalance = bbalance + :delta where bid = :bid; (6) insert into history(tid,bid,aid,delta) values(:tid,:bid,:aid,:delta); (7) end; o License? Basically it is same as BSD license. See pgbench.c for more details. o History 2003/06/10 * fix uninitialized memory bug * add support for PGHOST, PGPORT, PGUSER environment variables 2002/07/20 * patch contributed by Neil Conway. * code/document clean up and add -l option. 2002/02/24 * do not CHECKPOINT anymore while initializing benchmark * database. Add -N option. 2001/10/24 * "time"->"mtime" 2001/09/09 * Add -U, -P, -C options 2000/1/15 pgbench-1.2 contributed to PostgreSQL * Add -v option 1999/09/29 pgbench-1.1 released * Apply cygwin patches contributed by Yutaka Tanida * More robust when backends die * Add -S option (select only) 1999/09/04 pgbench-1.0 released