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Introduction 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 extensibility capabilities of PostgreSQL. These tests have recently been revised by Marc Fournier and Thomas Lockhart to become current for PostgreSQL v6.1. The tests are now packaged as functional units and should be easier to run and easier to interpret. 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. Preparation The regression test is invoked by the 'make' command which compiles a 'c' program with PostgreSQL extension functions 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. The postmaster should be invoked with the system time zone set for Berkeley, California. On many systems, this can be accomplished by setting the TZ environment variable before starting the postmaster (for csh/bash; use set/export for some other shells): setenv TZ PST8PDT date /usr/local/pgsql/bin/postmaster -s 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 TZ PST8PDT7,M04.01.0,M10.05.03 Directory Layout 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. Running the regression test If you have prevously invoked the regression test, clean up the working directory with: make clean The regression test is invoked with the command: make all runtest 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. Comparing expected/actual output The results are in files in the ./results directory. These results can be compared with results in the ./expected directory using 'diff'. The files might not compare exactly. The following paragraphs attempt to explain the differences. Error message differences 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. OID differences 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. DATE/TIME differences On many supported platforms, you can force PostgreSQL to believe that it is running in the same time zone as Berkeley, California. See details in the section on how to run the regression tests. If you do not explicitly set your time zone environment to PST8PDT, then most of the date and time results will reflect your local time zone and will fail the regression testing. There appears to be some systems which do not accept the recommended syntax for explicitly setting the local time zone rules. Some systems using the public domain time zone package exhibit minor problems with pre-1970 PDT times, representing them in PST instead. FLOATING POINT differences Some of the tests involve computing 64-bit (FLOAT8) number from table columns. Differences in results involving mathematical functions of FLOAT8 columns have been observed. These differences occur where different operating systems are used on the same platform ie: BSDI and SOLARIS on Intel/86, and where the same operating system is used used on different platforms, ie: SOLARIS on SPARC and Intel/86. 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. POLYGON differences 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; Random differences 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. 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' files 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. Current release notes (Thomas.Lockhart@jpl.nasa.gov) The regression tests have been adapted and extensively modified for the v6.1 release of PostgreSQL. Three new data types (datetime, timespan, and circle) have been added to the native set of PostgreSQL types. Points, boxes, paths, and polygons have had their output formats made consistant across the data types. The polygon output in misc.out has only been spot-checked for correctness relative to the original regression output. PostgreSQL v6.1 introduces a new, alternate optimizer which uses "genetic" algorithms. These algorithms introduce a random behavior in the ordering of query results when the query contains multiple qualifiers or multiple tables (giving the optimizer a choice on order of evaluation). Several regression tests have been modified to explicitly order the results, and hence are insensitive to optimizer choices. A few regression tests are for data types which are inherently unordered (e.g. points and time intervals) and tests involving those types are explicitly bracketed with "set geqo to 'off'" and "reset geqo". The interpretation of array specifiers (the curly braces around atomic values) appears to have changed sometime after the original regression tests were generated. The current ./expected/*.out files reflect this new interpretation, which may not be correct! The float8 regression test fails on at least some platforms. This is due to differences in implementations of pow() and exp() and the signaling mechanisms used for overflow and underflow conditions. The "random" results in the random test should cause the "random" test to be "failed", since the regression tests are evaluated using a simple diff. However, "random" does not seem to produce random results on my test machine (Linux/gcc/i686). Sample timing results Timing under Linux 2.0.27 seems to have a roughly 5% variation from run to run, presumably due to the timing vagaries of multitasking systems. Time System 06:12 Pentium Pro 180, 32MB, Linux 2.0.30, gcc 2.7.2 -O2 -m486 12:06 P-100, 48MB, Linux 2.0.29, gcc 39:58 Sparc IPC 32MB, Solaris 2.5, gcc 2.7.2.1 -O -g