Regression test instructions and analysis. The PostgreSQL regression tests are a comprehensive set of tests for the SQL implementation embedded in PostgreSQL developed by Jolly Chen and Andrew Yu. It tests standard SQL operations as well as the extended capabilities of PostgreSQL. These tests have recently been revised by Marc Fournier and Thomas Lockhart and are now packaged as functional units which should make them easier to run and easier to interpret. From PostgreSQL v6.1 onward the regression tests are current for every official release. Some properly installed and fully functional PostgreSQL installations can fail some of these regression tests due to artifacts of floating point representation and time zone support. The current tests are evaluated using a simple "diff" algorithm, and are sensitive to small system differences. For apparently failed tests, examining the differences may reveal that the differences are not significant. The regression testing notes below assume the following (except where noted): Commands are Unix-compatible. See note below. Defaults are used except where noted. User postgres is the Postgres superuser. The source path is /usr/src/pgsql (other paths are possible). The runtime path is /usr/local/pgsql (other paths are possible). The regression test is invoked by the make command which compiles a C program into a shared library in the current directory. Localized shell scripts are also created in the current directory. The output file templates are massaged into the ./expected/*.out files. The localization replaces macros in the source files with absolute pathnames and user names. Normally, the regression test should be run as the pg_superuser since the 'src/test/regress' directory and sub-directories are owned by the pg_superuser. If you run the regression test as another user the 'src/test/regress' directory tree should be writeable to that user. It was formerly necessary to run the postmaster with system time zone set to PST, but this is no longer required. You can run the regression tests under your normal postmaster configuration. The test script will set the PGTZ environment variable to ensure that timezone-dependent tests produce the expected results. However, your system must provide library support for the PST8PDT time zone, or the timezone-dependent tests will fail. To verify that your machine does have this support, type the following: setenv TZ PST8PDT date The "date" command above should have returned the current system time in the PST8PDT time zone. If the PST8PDT database is not available, then your system may have returned the time in GMT. If the PST8PDT time zone is not available, you can set the time zone rules explicitly: setenv PGTZ PST8PDT7,M04.01.0,M10.05.03 This should become a table in the previous section. input/ .... .source files that are converted using 'make all' into some of the .sql files in the 'sql' subdirectory output/ ... .source files that are converted using 'make all' into .out files in the 'expected' subdirectory sql/ ...... .sql files used to perform the regression tests expected/ . .out files that represent what we *expect* the results to look like results/ .. .out files that represent what the results *actually* look like. Also used as temporary storage for table copy testing. Commands were tested on RedHat Linux version 4.2 using the bash shell. Except where noted, they will probably work on most systems. Commands like ps and tar vary wildly on what options you should use on each platform. Use common sense before typing in these commands. For a fresh install or upgrading from previous releases of Postgres: The file /usr/src/pgsql/src/test/regress/README has detailed instructions for running and interpreting the regression tests. A short version follows here: If the postmaster is not already running, start the postmaster on an available window by typing postmaster or start the postmaster daemon running in the background by typing cd nohup postmaster > regress.log 2>&1 & Run postmaster from your Postgres super user account (typically account postgres). Do not run postmaster from the root account. If you have previously invoked the regression test, clean up the working directory with: cd /usr/src/pgsql/src/test/regress gmake clean You do not need to type "gmake clean" if this is the first time you are running the tests. Build the regression test. Type cd /usr/src/pgsql/src/test/regress gmake all Run the regression tests. Type cd /usr/src/pgsql/src/test/regress gmake runtest You should get on the screen (and also written to file ./regress.out) a series of statements stating which tests passed and which tests failed. Please note that it can be normal for some of the tests to "fail". For the failed tests, use diff to compare the files in directories ./results and ./expected. If float8 failed, type something like: cd /usr/src/pgsql/src/test/regress diff -w expected/float8.out results After running the tests and examining the results, type destroydb regression cd /usr/src/pgsql/src/test/regress gmake clean to recover the temporary disk space used by the tests. The results are in files in the ./results directory. These results can be compared with results in the ./expected directory using 'diff'. (The test script does this for you, and leaves the differences in ./regression.diffs.) The files might not compare exactly. The test script will report any difference as a "failure", but the difference might be due to small cross-system differences in error message wording, math library behavior, etc. "Failures" of this type do not indicate a problem with Postgres. Thus, it is necessary to examine the actual differences for each "failed" test to determine whether there is really a problem. The following paragraphs attempt to provide some guidance in determining whether a difference is significant or not. Some of the regression tests involve intentional invalid input values. Error messages can come from either the Postgres code or from the host platform system routines. In the latter case, the messages may vary between platforms, but should reflect similar information. These differences in messages will result in a "failed" regression test which can be validated by inspection. There are several places where PostgreSQL OID (object identifiers) appear in 'regress.out'. OID's are unique 32-bit integers which are generated by the PostgreSQL backend whenever a table row is inserted or updated. If you run the regression test on a non-virgin database or run it multiple times, the OID's reported will have different values. The following SQL statements in 'misc.out' have shown this behavior: QUERY: SELECT user_relns() AS user_relns ORDER BY user_relns; The 'a,523676' row is composed from an OID. Most of the date and time results are dependent on timezone environment. The reference files are generated for timezone PST8PDT (Berkeley, California) and there will be apparent failures if the tests are not run with that timezone setting. The regression test driver sets environment variable PGTZ to PST8PDT to ensure proper results. There appear to be some systems which do not accept the recommended syntax for explicitly setting the local time zone rules; you may need to use a different PGTZ setting on such machines. Some systems using older timezone libraries fail to apply daylight-savings corrections to pre-1970 dates, causing pre-1970 PDT times to be displayed in PST instead. This will result in localized differences in the test results. Some of the tests involve computing 64-bit (float8) numbers from table columns. Differences in results involving mathematical functions of float8 columns have been observed. The float8 and geometry tests are particularly prone to small differences across platforms. Human eyeball comparison is needed to determine the real significance of these differences which are usually 10 places to the right of the decimal point. Some systems signal errors from pow() and exp() differently from the mechanism expected by the current Postgres code. Several of the tests involve operations on geographic date about the Oakland/Berkley CA street map. The map data is expressed as polygons whose vertices are represented as pairs of float8 numbers (decimal latitude and longitude). Initially, some tables are created and loaded with geographic data, then some views are created which join two tables using the polygon intersection operator (##), then a select is done on the view. When comparing the results from different platforms, differences occur in the 2nd or 3rd place to the right of the decimal point. The SQL statements where these problems occur are the folowing: QUERY: SELECT * from street; QUERY: SELECT * from iexit; There is at least one test case in random.out which is intended to produce random results. This causes random to fail the regression testing once in a while. Typing diff results/random.out expected/random.out should produce only one or a few lines of differences for this reason, but other floating point differences on dissimilar architectures might cause many more differences. See the release notes below. The ./expected/*.out files were adapted from the original monolithic expected.input file provided by Jolly Chen et al. Newer versions of these files generated on various development machines have been substituted after careful (?) inspection. Many of the development machines are running a Unix OS variant (FreeBSD, Linux, etc) on Ix86 hardware. The original expected.input file was created on a SPARC Solaris 2.4 system using the postgres5-1.02a5.tar.gz source tree. It was compared with a file created on an I386 Solaris 2.4 system and the differences were only in the floating point polygons in the 3rd digit to the right of the decimal point. (see below) The original sample.regress.out file was from the postgres-1.01 release constructed by Jolly Chen and is included here for reference. It may have been created on a DEC ALPHA machine as the Makefile.global in the postgres-1.01 release has PORTNAME=alpha.