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 alone, while the parallel method starts up multiple server processes to run groups of tests in parallel. Parallel testing adds confidence that interprocess communication and locking are working correctly.
To run the parallel regression tests after building but before installation, type:
in the top-level directory. (Or you can change to src/test/regress and run the command there.) At the end you should see something like:
or otherwise a note about which tests failed. See Section 32.2 below before assuming that a “failure” represents a serious problem.
Because this test method runs a temporary server, it will not work if you did the build as the root user, since the server will not start as root. Recommended procedure is not to do the build as root, or else to perform testing after completing the installation.
If you have configured PostgreSQL to install into a location where an older PostgreSQL installation already exists, and you perform make check before installing the new version, you might 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 might 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:
runs no more than ten tests concurrently.
To run the tests after installation (see Chapter 16), initialize a data area and start the server as explained in Chapter 18, then type:
or for a parallel test:
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 tests will be run in a database named regression; any existing database by this name will be dropped.
The tests will also transiently create some cluster-wide objects, such as roles and tablespaces. These objects will have names beginning with regress_. Beware of using installcheckmode in installations that have any actual users or tablespaces named that way.
The make check and make installcheck commands run only the “core” regression tests, which test built-in functionality of the PostgreSQL server. The source distribution also contains additional test suites, most of them having to do with add-on functionality such as optional procedural languages.
To run all test suites applicable to the modules that have been selected to be built, including the core tests, type one of these commands at the top of the build tree:
These commands run the tests using temporary servers or an already-installed server, respectively, just as previously explained for make check and make installcheck. Other considerations are the same as previously explained for each method. Note that make check-world builds a separate temporary installation tree for each tested module, so it requires a great deal more time and disk space than make installcheck-world.
Alternatively, you can run individual test suites by typing make check or make installcheck in the appropriate subdirectory of the build tree. Keep in mind that make installcheckassumes you've installed the relevant module(s), not only the core server.
The additional tests that can be invoked this way include:
Regression tests for optional procedural languages (other than PL/pgSQL, which is tested by the core tests). These are located under src/pl.
Regression tests for contrib modules, located under contrib. Not all contrib modules have tests.
Regression tests for the ECPG interface library, located in src/interfaces/ecpg/test.
Tests stressing behavior of concurrent sessions, located in src/test/isolation.
Tests of client programs under src/bin. See also Section 32.4.
When using installcheck mode, these tests will destroy any existing databases named pl_regression, contrib_regression, isolation_regression, ecpg1_regression, or ecpg2_regression, as well as regression.
The TAP-based tests are run only when PostgreSQL was configured with the option --enable-tap-tests. This is recommended for development, but can be omitted if there is no suitable Perl installation.
By default, tests using a temporary installation use the locale defined in the current environment and the corresponding database encoding as determined by initdb. It can be useful to test different locales by setting the appropriate environment variables, for example:
For implementation reasons, setting LC_ALL does not work for this purpose; all the other locale-related environment variables do work.
When testing against an existing installation, the locale is determined by the existing database cluster and cannot be set separately for the test run.
You can also choose the database encoding explicitly by setting the variable ENCODING, for example:
Setting the database encoding this way typically only makes sense if the locale is C; otherwise the encoding is chosen automatically from the locale, and specifying an encoding that does not match the locale will result in an error.
The database encoding can be set for tests against either a temporary or an existing installation, though in the latter case it must be compatible with the installation's locale.
The core regression test suite contains a few test files that are not run by default, because they might be platform-dependent or take a very long time to run. You can run these or other extra test files by setting the variable EXTRA_TESTS. For example, to run the numeric_big test:
To run the collation tests:
The collate.linux.utf8 test works only on Linux/glibc platforms. The collate.icu.utf8 test only works when support for ICU was built. Both tests will only succeed when run in a database that uses UTF-8 encoding.
The source distribution also contains regression tests for the static behavior of Hot Standby. These tests require a running primary server and a running standby server that is accepting new WAL changes from the primary (using either file-based log shipping or streaming replication). Those servers are not automatically created for you, nor is replication setup documented here. Please check the various sections of the documentation devoted to the required commands and related issues.
To run the Hot Standby tests, first create a database called regression on the primary:
Next, run the preparatory script src/test/regress/sql/hs_primary_setup.sql on the primary in the regression database, for example:
Allow these changes to propagate to the standby.
Now arrange for the default database connection to be to the standby server under test (for example, by setting the PGHOST and PGPORT environment variables). Finally, run make standbycheck in the regression directory:
Some extreme behaviors can also be generated on the primary using the script src/test/regress/sql/hs_primary_extremes.sql to allow the behavior of the standby to be tested.
Since some of the tests inherently produce environment-dependent results, we have provided ways to specify alternate “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
The test name is just the name of the particular regression test module. The output value indicates which output file to check. For the standard regression tests, this is always out. The value corresponds to the file extension of the output file. 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:
which will trigger on any machine where 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.
Various tests, particularly the client program tests under src/bin, use the Perl TAP tools and are run using the Perl testing program prove. You can pass command-line options to proveby setting the make variable PROVE_FLAGS, for example:
See the manual page of prove for more information.
The TAP tests require the Perl module IPC::Run. This module is available from CPAN or an operating system package.
The PostgreSQL source code can be compiled with coverage testing instrumentation, so that it becomes possible to examine which parts of the code are covered by the regression tests or any other test suite that is run with the code. This is currently supported when compiling with GCC and requires the gcov and lcov programs.
A typical workflow would look like this:
Then point your HTML browser to coverage/index.html. The make commands also work in subdirectories.
To reset the execution counts between test runs, run:
迴歸測試（Regression Tests）是 PostgreSQL 中 SQL 實作的一套綜合測試方式。他們測試標準的 SQL 操作以及 PostgreSQL 的延伸功能。
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 might 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. (When running a test suite other than the core tests, these files of course appear in the relevant subdirectory, not src/test/regress.)
If you don't like the diff options that are used by default, set the environment variable PG_REGRESS_DIFF_OPTS, for instance PG_REGRESS_DIFF_OPTS='-u'. (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 Section 32.3 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 can 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 a server that was initialized with a collation-order locale other than C, then there might be differences due to sort order and subsequent failures. The regression test suite is set up to handle this problem by providing alternate result files that together are known to handle a large number of locales.
To run the tests in a different locale when using the temporary-installation method, pass the appropriate locale-related environment variables on the make command line, for example:
(The regression test driver unsets LC_ALL, so it does not work to choose the locale using that variable.) To use no locale, either unset all locale-related environment variables (or set them to C) or use the following special invocation:
When running the tests against an existing installation, the locale setup is determined by the existing installation. To change it, initialize the database cluster with a different locale by passing the appropriate options to initdb.
In general, it is advisable to try to run the regression tests in the locale setup that is wanted for production use, as this will exercise the locale- and encoding-related code portions that will actually be used in production. Depending on the operating system environment, you might get failures, but then you will at least know what locale-specific behaviors to expect when running real applications.
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 precisioncolumns have been observed. The float8 and geometry tests are particularly prone to small differences across platforms, or even with different compiler optimization settings. 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 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, so the lack of ORDER BY is not 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. However, please report it anyway, so that we can add an ORDER BY to that particular query to 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_depthparameter 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.
On platforms supporting getrlimit(), the server should automatically choose a safe value of max_stack_depth; so unless you've manually overridden this setting, a failure of this kind is a reportable bug.
The random test script is intended to produce random results. In very rare cases, this causes that regression test to fail. Typing:
should produce only one or a few lines of differences. You need not worry unless the random test fails repeatedly.
When running the tests against an existing installation, some non-default parameter settings could cause the tests to fail. For example, changing parameters such as enable_seqscan or enable_indexscan could cause plan changes that would affect the results of tests that use EXPLAIN.