regression tests test The regression tests are a comprehensive set of tests for the SQL implementation in PostgreSQL. They test standard SQL operations as well as the extended capabilities of PostgreSQL. The regression tests can be run against an already installed and running server, or using a temporary installation within the build tree. Furthermore, there is a parallel and a sequential mode for running the tests. The sequential method runs each test script in turn, whereas the parallel method starts up multiple server processes to run groups of tests in parallel. Parallel testing gives confidence that interprocess communication and locking are working correctly. For historical reasons, the sequential test is usually run against an existing installation and the parallel method against a temporary installation, but there are no technical reasons for this. To run the regression tests after building but before installation, type gmake check in the top-level directory. (Or you can change to src/test/regress and run the command there.) This will first build several auxiliary files, such as some sample user-defined trigger functions, and then run the test driver script. At the end you should see something like ====================== All 100 tests passed. ====================== or otherwise a note about which tests failed. See below before assuming that a failure represents a serious problem. Because this test method runs a temporary server, it will not work when you are the root user (since the server will not start as root). If you already did the build as root, you do not have to start all over. Instead, make the regression test directory writable by some other user, log in as that user, and restart the tests. For example root# chmod -R a+w src/test/regress root# chmod -R a+w contrib/spi root# su - joeuser joeuser$ cd top-level build directory joeuser$ gmake check (The only possible security risk here is that other users might be able to alter the regression test results behind your back. Use common sense when managing user permissions.) Alternatively, run the tests after installation. If you have configured PostgreSQL to install into a location where an older PostgreSQL installation already exists, and you perform gmake check before installing the new version, you may find that the tests fail because the new programs try to use the already-installed shared libraries. (Typical symptoms are complaints about undefined symbols.) If you wish to run the tests before overwriting the old installation, you'll need to build with configure --disable-rpath. It is not recommended that you use this option for the final installation, however. The parallel regression test starts quite a few processes under your user ID. Presently, the maximum concurrency is twenty parallel test scripts, which means forty processes: there's a server process and a psql process for each test script. So if your system enforces a per-user limit on the number of processes, make sure this limit is at least fifty or so, else you may get random-seeming failures in the parallel test. If you are not in a position to raise the limit, you can cut down the degree of parallelism by setting the MAX_CONNECTIONS parameter. For example, gmake MAX_CONNECTIONS=10 check runs no more than ten tests concurrently. To run the tests after installation)]]>, initialize a data area and start the server, , ]]> then type gmake installcheck or for a parallel test gmake installcheck-parallel The tests will expect to contact the server at the local host and the default port number, unless directed otherwise by PGHOST and PGPORT environment variables. The source distribution also contains regression tests for the optional procedural languages and for some of the contrib modules. At present, these tests can be used only against an already-installed server. To run the tests for all procedural languages that have been built and installed, change to the src/pl directory of the build tree and type gmake installcheck You can also do this in any of the subdirectories of src/pl to run tests for just one procedural language. To run the tests for all contrib modules that have them, change to the contrib directory of the build tree and type gmake installcheck The contrib modules must have been built and installed first. You can also do this in a subdirectory of contrib to run the tests for just one module. Some properly installed and fully functional PostgreSQL installations can fail some of these regression tests due to platform-specific artifacts such as varying floating-point representation and message wording. The tests are currently evaluated using a simple diff comparison against the outputs generated on a reference system, so the results are sensitive to small system differences. When a test is reported as failed, always examine the differences between expected and actual results; you may well find that the differences are not significant. Nonetheless, we still strive to maintain accurate reference files across all supported platforms, so it can be expected that all tests pass. The actual outputs of the regression tests are in files in the src/test/regress/results directory. The test script uses diff to compare each output file against the reference outputs stored in the src/test/regress/expected directory. Any differences are saved for your inspection in src/test/regress/regression.diffs. (Or you can run diff yourself, if you prefer.) If for some reason a particular platform generates a failure for a given test, but inspection of the output convinces you that the result is valid, you can add a new comparison file to silence the failure report in future test runs. See for details. Some of the regression tests involve intentional invalid input values. Error messages can come from either the PostgreSQL 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 that can be validated by inspection. If you run the tests against an already-installed server that was initialized with a collation-order locale other than C, then there may be differences due to sort order and follow-up failures. The regression test suite is set up to handle this problem by providing alternative result files that together are known to handle a large number of locales. Most of the date and time results are dependent on the time zone environment. The reference files are generated for time zone PST8PDT (Berkeley, California), and there will be apparent failures if the tests are not run with that time zone setting. The regression test driver sets environment variable PGTZ to PST8PDT, which normally ensures proper results. Some of the tests involve computing 64-bit floating-point numbers (double precision) from table columns. Differences in results involving mathematical functions of double precision columns have been observed. The float8 and geometry tests are particularly prone to small differences across platforms, or even with different compiler optimization options. 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 display minus zero as -0, while others just show 0. Some systems signal errors from pow() and exp() differently from the mechanism expected by the current PostgreSQL code. You might see differences in which the same rows are output in a different order than what appears in the expected file. In most cases this is not, strictly speaking, a bug. Most of the regression test scripts are not so pedantic as to use an ORDER BY for every single SELECT, and so their result row orderings are not well-defined according to the letter of the SQL specification. In practice, since we are looking at the same queries being executed on the same data by the same software, we usually get the same result ordering on all platforms, and so the lack of ORDER BY isn't a problem. Some queries do exhibit cross-platform ordering differences, however. When testing against an already-installed server, ordering differences can also be caused by non-C locale settings or non-default parameter settings, such as custom values of work_mem or the planner cost parameters. Therefore, if you see an ordering difference, it's not something to worry about, unless the query does have an ORDER BY that your result is violating. But please report it anyway, so that we can add an ORDER BY to that particular query and thereby eliminate the bogus failure in future releases. You might wonder why we don't order all the regression test queries explicitly to get rid of this issue once and for all. The reason is that that would make the regression tests less useful, not more, since they'd tend to exercise query plan types that produce ordered results to the exclusion of those that don't. If the errors test results in a server crash at the select infinite_recurse() command, it means that the platform's limit on process stack size is smaller than the ]]> max_stack_depth]]> parameter indicates. This can be fixed by running the server under a higher stack size limit (4MB is recommended with the default value of max_stack_depth). If you are unable to do that, an alternative is to reduce the value of max_stack_depth. The random test script is intended to produce random results. In rare cases, this causes the random regression test to fail. Typing diff results/random.out expected/random.out should produce only one or a few lines of differences. You need not worry unless the random test fails repeatedly. Since some of the tests inherently produce environment-dependent results, we have provided ways to specify alternative expected result files. Each regression test can have several comparison files showing possible results on different platforms. There are two independent mechanisms for determining which comparison file is used for each test. The first mechanism allows comparison files to be selected for specific platforms. There is a mapping file, src/test/regress/resultmap, that defines which comparison file to use for each platform. To eliminate bogus test failures for a particular platform, you first choose or make a variant result file, and then add a line to the resultmap file. Each line in the mapping file is of the form testname/platformpattern=comparisonfilename The test name is just the name of the particular regression test module. The platform pattern is a pattern in the style of the Unix tool expr (that is, a regular expression with an implicit ^ anchor at the start). It is matched against the platform name as printed by config.guess. The comparison file name is the base name of the substitute result comparison file. For example: some systems interpret very small floating-point values as zero, rather than reporting an underflow error. This causes a few differences in the float8 regression test. Therefore, we provide a variant comparison file, float8-small-is-zero.out, which includes the results to be expected on these systems. To silence the bogus failure message on OpenBSD platforms, resultmap includes float8/i.86-.*-openbsd=float8-small-is-zero which will trigger on any machine for which the output of config.guess matches i.86-.*-openbsd. Other lines in resultmap select the variant comparison file for other platforms where it's appropriate. The second selection mechanism for variant comparison files is much more automatic: it simply uses the best match among several supplied comparison files. The regression test driver script considers both the standard comparison file for a test, testname.out, and variant files named testname_digit.out (where the digit is any single digit 0-9). If any such file is an exact match, the test is considered to pass; otherwise, the one that generates the shortest diff is used to create the failure report. (If resultmap includes an entry for the particular test, then the base testname is the substitute name given in resultmap.) For example, for the char test, the comparison file char.out contains results that are expected in the C and POSIX locales, while the file char_1.out contains results sorted as they appear in many other locales. The best-match mechanism was devised to cope with locale-dependent results, but it can be used in any situation where the test results cannot be predicted easily from the platform name alone. A limitation of this mechanism is that the test driver cannot tell which variant is actually correct for the current environment; it will just pick the variant that seems to work best. Therefore it is safest to use this mechanism only for variant results that you are willing to consider equally valid in all contexts.