PostgreSQL 回归测试
背景
回归测试是PostgreSQL的测试方法之一。
回归测试，需要事先定义好测试脚本（通常是SQL脚本，放在sql目录中），同时定义好调用执行测试脚本的预期正确输出文件（通常放在expected目录中)。
测试使用make check或make installcheck进行，它会通过pg_regress程序调用sql目录中的SQL，并收集输出结果（通常放到results目录中），最后pg_regress会对expected目录和results目录中的文件使用diff进行一一比较。
如果比较发现文件内容不一致，会将不一致的结果输出到regression.diffs文件中，并返回这个TEST CASE failed。
但是这种测试方法实际上有一些需要注意的地方，例如我们使用不同的本地化设置，时区可能得到的结果和期望的结果就不一样。另外有些不可预知的结果，例如随机值，数据的顺序，执行计划和优化器相关参数有关。这些因素都可能导致测试结果和预期不一致，那么我们就需要人为去修复这种failed。
PostgreSQL的主代码测试文件在src/test/regress目录中。
这个目录的结构如下：
postgres@digoal-> ll -rt
total 1.2M
-rw-r--r-- 1 postgres postgres 579 Jun 10 03:29 standby_schedule 测试standby的调度配置, 其实就是调度sql里的文件名
-rw-r--r-- 1 postgres postgres 2.3K Jun 10 03:29 serial_schedule 串行测试的调度配置
-rw-r--r-- 1 postgres postgres 937 Jun 10 03:29 resultmap 不同的测试平台的结果映射文件，因为不同平台某些测试结果可能不相同，所以一个expected文件不能支持所有的平台。例如浮点数测试。
-rwxr-xr-x 1 postgres postgres 4.4K Jun 10 03:29 regressplans.sh
-rw-r--r-- 1 postgres postgres 20K Jun 10 03:29 regress.c
-rw-r--r-- 1 postgres postgres 159 Jun 10 03:29 README
-rw-r--r-- 1 postgres postgres 2.7K Jun 10 03:29 pg_regress_main.c
-rw-r--r-- 1 postgres postgres 1.6K Jun 10 03:29 pg_regress.h
-rw-r--r-- 1 postgres postgres 69K Jun 10 03:29 pg_regress.c
-rw-r--r-- 1 postgres postgres 3.6K Jun 10 03:29 parallel_schedule 并行测试的调度配置
-rw-r--r-- 1 postgres postgres 624 Jun 10 03:29 Makefile
-rw-r--r-- 1 postgres postgres 5.6K Jun 10 03:29 GNUmakefile
drwxrwxrwx 2 postgres postgres 4.0K Jun 10 03:38 output
drwxrwxrwx 2 postgres postgres 4.0K Jun 10 03:38 input
drwxrwxrwx 2 postgres postgres 4.0K Jun 10 03:38 data 一些测试数据
drwxrwxrwx 2 postgres postgres 4.0K Sep 7 14:51 sql 测试用到的SQL
drwxrwxr-x 2 postgres postgres 4.0K Sep 7 14:52 results 通过pg_regress调用sql目录中的脚本，得到的结果
drwxrwxrwx 2 postgres postgres 4.0K Sep 7 14:51 expected 执行sql目录中的文件对应的正确返回结果
上层目录结构如下，其中包含了一些其他的测试目标，例如隔离级别的测试，本地化测试，性能测试，线程安全测试。等。
postgres@digoal-> cd /opt/soft_bak/postgresql-9.4.4/src/test
postgres@digoal-> ll
total 36K
drwxrwxrwx 2 postgres postgres 4.0K Jun 10 03:38 examples
drwxrwxrwx 4 postgres postgres 4.0K Jun 10 03:41 isolation
drwxrwxrwx 6 postgres postgres 4.0K Jun 10 03:38 locale
-rw-r--r-- 1 postgres postgres 389 Jun 10 03:29 Makefile
drwxrwxrwx 4 postgres postgres 4.0K Jun 10 03:38 mb
drwxrwxrwx 4 postgres postgres 4.0K Jun 10 03:38 performance
drwxrwxrwx 2 postgres postgres 4.0K Jun 10 03:38 perl
drwxrwxrwx 10 postgres postgres 4.0K Sep 7 19:17 regress
drwxrwxrwx 2 postgres postgres 4.0K Jun 10 03:38 thread
接下来我们看看PostgreSQL的回归测试程序pg_regress的用法，它不会安装到PGHOME/bin中，只在src/test/regress中存在。
$ cd src/test/regress
$ src/test/regress/pg_regress --help
PostgreSQL regression test driver
Usage:
pg_regress [OPTION]... [EXTRA-TEST]...
Options:
--config-auth=DATADIR update authentication settings for DATADIR
--create-role=ROLE create the specified role before testing
--dbname=DB use database DB (default "regression")
--debug turn on debug mode in programs that are run
--dlpath=DIR look for dynamic libraries in DIR
--encoding=ENCODING use ENCODING as the encoding
--inputdir=DIR take input files from DIR (default ".")
--launcher=CMD use CMD as launcher of psql
--load-extension=EXT load the named extension before running the
tests; can appear multiple times
--load-language=LANG load the named language before running the
tests; can appear multiple times
--max-connections=N maximum number of concurrent connections
(default is 0, meaning unlimited)
--outputdir=DIR place output files in DIR (default ".")
--schedule=FILE use test ordering schedule from FILE
(can be used multiple times to concatenate)
--temp-install=DIR create a temporary installation in DIR
--use-existing use an existing installation
Options for "temp-install" mode:
--extra-install=DIR additional directory to install (e.g., contrib)
--no-locale use C locale
--port=PORT start postmaster on PORT
--temp-config=FILE append contents of FILE to temporary config
--top-builddir=DIR (relative) path to top level build directory
Options for using an existing installation:
--host=HOST use postmaster running on HOST
--port=PORT use postmaster running at PORT
--user=USER connect as USER
--psqldir=DIR use psql in DIR (default: configured bindir)
The exit status is 0 if all tests passed, 1 if some tests failed, and 2
if the tests could not be run for some reason.
Report bugs to <pgsql-bugs@postgresql.org>.
回归测试用法
在PostgreSQL源码根目录，或者源码的regress目录中执行如下：
make check // 测试时需要初始化数据库集群
make installcheck // 使用以及启动的数据库集群测试，不需要初始化数据库集群
以下同时测试主代码以及contrib的代码：
make check-world
make installcheck-world
如果要使用自定义的diff参数，可以设置一个环境变量，
例如：make check PG_REGRESS_DIFF_OPTS=’-u’。
同时我们还可以使用不同的LOCALE进行测试。例如：
make check LANG=de_DE.utf8
make check NO_LOCALE=1
make check LANG=C ENCODING=EUC_JP
当我们要测试调度中不包含的测试SQL时，可以使用EXTRA_TESTS参数，至于这些脚本为什么默认不包含在调度中，可能是因为这些SQL脚本可能对平台的依赖比较严重，所以没有放到默认的测试中。例如：
make check EXTRA_TESTS=collate.linux.utf8 LANG=en_US.utf8
make check EXTRA_TESTS=numeric_big
接下来我们看看调度文件以及sql脚本目录：
postgres@digoal-> pwd
/opt/soft_bak/postgresql-9.4.4/src/test/regress
postgres@digoal-> less serial_schedule
# src/test/regress/serial_schedule
# This should probably be in an order similar to parallel_schedule.
test: tablespace
test: boolean
test: char
test: name
test: varchar
test: text
test: int2
test: int4
test: int8
......
并行调度
postgres@digoal-> less parallel_schedule
# ----------
# src/test/regress/parallel_schedule
#
# By convention, we put no more than twenty tests in any one parallel group;
# this limits the number of connections needed to run the tests.
# ----------
# run tablespace by itself, and first, because it forces a checkpoint;
# we'd prefer not to have checkpoints later in the tests because that
# interferes with crash-recovery testing.
test: tablespace
# ----------
# The first group of parallel tests
# ----------
test: boolean char name varchar text int2 int4 int8 oid float4 float8 bit numeric txid uuid enum money rangetypes pg_lsn regproc
......
调度文件的test:后面跟的就是sql目录下的文件名(不含.sql后缀)。
postgres@digoal-> less sql/
total 1940
drwxrwxrwx 2 postgres postgres 4096 Sep 7 14:51 ./
drwxrwxrwx 10 postgres postgres 4096 Sep 7 22:34 ../
-rw-r--r-- 1 postgres postgres 2237 Jun 10 03:29 abstime.sql
-rw-r--r-- 1 postgres postgres 4097 Jun 10 03:29 advisory_lock.sql
-rw-r--r-- 1 postgres postgres 20295 Jun 10 03:29 aggregates.sql
-rw-r--r-- 1 postgres postgres 24882 Jun 10 03:29 alter_generic.sql
-rw-r--r-- 1 postgres postgres 54461 Jun 10 03:29 alter_table.sql
-rw-r--r-- 1 postgres postgres 17244 Jun 10 03:29 arrays.sql
-rw-r--r-- 1 postgres postgres 594 Jun 10 03:29 async.sql
-rw-r--r-- 1 postgres postgres 1365 Jun 10 03:29 bitmapops.sql
-rw-r--r-- 1 postgres postgres 6406 Jun 10 03:29 bit.sql
-rw-r--r-- 1 postgres postgres 4164 Jun 10 03:29 boolean.sql
......
所以前面提到的EXTRA_TESTS实际上也是sql目录中的文件名(不带.sql后缀)。
make check EXTRA_TESTS=collate.linux.utf8 LANG=en_US.utf8
make check EXTRA_TESTS=numeric_big
来实际的试一下吧：
postgres@digoal-> pwd
/opt/soft_bak/postgresql-9.4.4/src/test/regress
postgres@digoal-> make installcheck-parallel //并行测试，使用已经开启的现有的数据库集群
make -C ../../../src/port all
......
../../../src/test/regress/pg_regress --inputdir=. --psqldir='/opt/pgsql9.4.4/bin' --dlpath=. --schedule=./parallel_schedule
(using postmaster on /data01/pg_root_1921, port 1921)
============== dropping database "regression" ==============
DROP DATABASE
============== creating database "regression" ==============
CREATE DATABASE
ALTER DATABASE
============== running regression test queries ==============
test tablespace ... ok
......
parallel group (19 tests): limit conversion sequence returning without_oid polymorphism copy2 xml prepare plancache rowtypes temp domain with truncate largeobject rangefuncs alter_table plpgsql
plancache ... ok
limit ... ok
plpgsql ... ok
copy2 ... ok
temp ... ok
domain ... ok
rangefuncs ... FAILED
prepare ... ok
without_oid ... ok
conversion ... ok
truncate ... ok
alter_table ... ok
sequence ... ok
polymorphism ... FAILED
rowtypes ... ok
returning ... ok
largeobject ... ok
with ... FAILED
xml ... ok
test stats ... ok
......
=========================
22 of 145 tests failed.
=========================
The differences that caused some tests to fail can be viewed in the
file "/opt/soft_bak/postgresql-9.4.4/src/test/regress/regression.diffs". A copy of the test summary that you see
above is saved in the file "/opt/soft_bak/postgresql-9.4.4/src/test/regress/regression.out".
make: *** [installcheck-parallel] Error 1
有些测试失败了，diff文件已经输出到/opt/soft_bak/postgresql-9.4.4/src/test/regress/regression.diffs，我们可以查看一下看看为什么测试结果和预期结果不一致。
postgres@digoal-> less regression.diffs
*** /opt/soft_bak/postgresql-9.4.4/src/test/regress/expected/pg_lsn.out 2015-06-10 03:29:38.000000000 +0800
--- /opt/soft_bak/postgresql-9.4.4/src/test/regress/results/pg_lsn.out 2015-09-07 22:45:04.413922536 +0800
***************
*** 72,92 ****
generate_series(1, 5) k
WHERE i <= 10 AND j > 0 AND j <= 10
ORDER BY f;
! QUERY PLAN
! --------------------------------------------------------------------------
! Sort
! Sort Key: (((((i.i)::text || '/'::text) || (j.j)::text))::pg_lsn)
! -> HashAggregate
! Group Key: ((((i.i)::text || '/'::text) || (j.j)::text))::pg_lsn
-> Nested Loop
-> Function Scan on generate_series k
! -> Materialize
! -> Nested Loop
! -> Function Scan on generate_series j
! Filter: ((j > 0) AND (j <= 10))
! -> Function Scan on generate_series i
! Filter: (i <= 10)
! (12 rows)
SELECT DISTINCT (i || '/' || j)::pg_lsn f
FROM generate_series(1, 10) i,
--- 72,90 ----
generate_series(1, 5) k
WHERE i <= 10 AND j > 0 AND j <= 10
ORDER BY f;
......
对于主代码，如果我们需要自定义测试SQL，我们可以修改regress/sql目录下的文件，或者新增文件。同时修改regress/expected目录下的对应期望文件，或者现在期望文件。
如果是新增文件的情况，我们还需要修改调度文件regress/serial_schedule和regress/parallel_schedule，把测试加入调度。
最后，再以ltree插件为例，看看如何配置一个外加插件的回归测试。
ltree的源码目录：
postgres@digoal-> cd contrib/
postgres@digoal-> cd ltree/
postgres@digoal-> ll -rt
total 1.1M
-rw-r--r-- 1 postgres postgres 517 Jun 10 03:29 Makefile
-rw-r--r-- 1 postgres postgres 2.4K Jun 10 03:29 ltxtquery_op.c
-rw-r--r-- 1 postgres postgres 11K Jun 10 03:29 ltxtquery_io.c
-rw-r--r-- 1 postgres postgres 7.9K Jun 10 03:29 ltree--unpackaged--1.0.sql
-rw-r--r-- 1 postgres postgres 994 Jun 10 03:29 ltreetest.sql
-rw-r--r-- 1 postgres postgres 13K Jun 10 03:29 ltree_op.c
-rw-r--r-- 1 postgres postgres 6.9K Jun 10 03:29 _ltree_op.c
-rw-r--r-- 1 postgres postgres 14K Jun 10 03:29 ltree_io.c
-rw-r--r-- 1 postgres postgres 7.3K Jun 10 03:29 ltree.h
-rw-r--r-- 1 postgres postgres 16K Jun 10 03:29 ltree_gist.c
-rw-r--r-- 1 postgres postgres 13K Jun 10 03:29 _ltree_gist.c
-rw-r--r-- 1 postgres postgres 155 Jun 10 03:29 ltree.control
-rw-r--r-- 1 postgres postgres 18K Jun 10 03:29 ltree--1.0.sql
-rw-r--r-- 1 postgres postgres 7.1K Jun 10 03:29 lquery_op.c
-rw-r--r-- 1 postgres postgres 263 Jun 10 03:29 crc32.h
-rw-r--r-- 1 postgres postgres 4.1K Jun 10 03:29 crc32.c
drwxrwxrwx 2 postgres postgres 4.0K Jun 10 03:38 sql
drwxrwxrwx 2 postgres postgres 4.0K Jun 10 03:38 expected
drwxrwxrwx 2 postgres postgres 4.0K Jun 10 03:38 data
contrib/ltree的Makefile如下（在这里配置回归测试的调度，用到变量REGRESS，对应sql目录中的脚本文件名）：
# contrib/ltree/Makefile
MODULE_big = ltree
OBJS = ltree_io.o ltree_op.o lquery_op.o _ltree_op.o crc32.o \
ltxtquery_io.o ltxtquery_op.o ltree_gist.o _ltree_gist.o
PG_CPPFLAGS = -DLOWER_NODE
EXTENSION = ltree
DATA = ltree--1.0.sql ltree--unpackaged--1.0.sql
REGRESS = ltree
ifdef USE_PGXS
PG_CONFIG = pg_config
PGXS := $(shell $(PG_CONFIG) --pgxs)
include $(PGXS)
else
subdir = contrib/ltree
top_builddir = ../..
include $(top_builddir)/src/Makefile.global
include $(top_srcdir)/contrib/contrib-global.mk
endif
其中：
include $(PGXS)
或 :
include $(top_builddir)/src/Makefile.global
都指向了：
src/makefiles/pgxs.mk
这个makefile中会用到回归测试相关的两个变量：
# REGRESS -- list of regression test cases (without suffix)
# REGRESS_OPTS -- additional switches to pass to pg_regress
引用src/makefiles/pgxs.mk的部分内容如下：
ifdef REGRESS
# Select database to use for running the tests
ifneq ($(USE_MODULE_DB),)
REGRESS_OPTS += --dbname=$(CONTRIB_TESTDB_MODULE)
else
REGRESS_OPTS += --dbname=$(CONTRIB_TESTDB)
endif
# where to find psql for running the tests
PSQLDIR = $(bindir)
# When doing a VPATH build, must copy over the data files so that the
# driver script can find them. We have to use an absolute path for
# the targets, because otherwise make will try to locate the missing
# files using VPATH, and will find them in $(srcdir), but the point
# here is that we want to copy them from $(srcdir) to the build
# directory.
ifdef VPATH
abs_builddir := $(shell pwd)
test_files_src := $(wildcard $(srcdir)/data/*.data)
test_files_build := $(patsubst $(srcdir)/%, $(abs_builddir)/%, $(test_files_src))
all: $(test_files_build)
$(test_files_build): $(abs_builddir)/%: $(srcdir)/%
$(MKDIR_P) $(dir $@)
ln -s $< $@
endif # VPATH
.PHONY: submake
submake:
ifndef PGXS
$(MAKE) -C $(top_builddir)/src/test/regress pg_regress$(X)
endif
# against installed postmaster
installcheck: submake $(REGRESS_PREP)
$(pg_regress_installcheck) $(REGRESS_OPTS) $(REGRESS)
ifdef PGXS
check:
@echo '"$(MAKE) check" is not supported.'
@echo 'Do "$(MAKE) install", then "$(MAKE) installcheck" instead.'
else
check: all submake $(REGRESS_PREP)
$(pg_regress_check) --extra-install=$(subdir) $(REGRESS_OPTS) $(REGRESS)
endif
endif # REGRESS
这里用到了ltree中Makefile中定义的subdir 和 REGRESS变量，如下：
top_builddir = ../..
subdir = contrib/ltree
REGRESS = ltree
所以我们在contrib/ltree中执行make check会执行：(指PGXS未定义时)
$(pg_regress_check) --extra-install=$(subdir) $(REGRESS_OPTS) $(REGRESS)
pg_regress_check这个变量在src/Makefile.global中定义了，其实就是pg_regress命令的调用：
src/Makefile.global
src/Makefile.global:srcdir = .
pg_regress_locale_flags = $(if $(ENCODING),--encoding=$(ENCODING)) $(NOLOCALE)
pg_regress_check = $(top_builddir)/src/test/regress/pg_regress --inputdir=$(srcdir) --temp-install=./tmp_check --top-builddir=$(top_builddir) $(pg_regress_locale_flags) $(EXTRA_REGRESS_OPTS)
在contrib/ltree中执行make check最终执行的是(没有定义的变量直接忽略)：
../../src/test/regress/pg_regress --inputdir=. --temp-install=./tmp_check --top-builddir=../.. --extra-install=contrib/ltree ltree
我们可以直接到ltree的源码目录测试这条命令：
[root@digoal ~]# chown -R postgres:postgres /opt/soft_bak/postgresql-9.4.4
[root@digoal ~]# su - postgres
postgres@digoal-> cd /opt/soft_bak/postgresql-9.4.4/contrib/ltree/
postgres@digoal-> ../../src/test/regress/pg_regress --inputdir=. --temp-install=./tmp_check --top-builddir=../.. --extra-install=contrib/ltree ltree
============== removing existing temp installation ==============
============== creating temporary installation ==============
============== initializing database system ==============
============== starting postmaster ==============
running on port 57636 with PID 27852
============== creating database "regression" ==============
CREATE DATABASE
ALTER DATABASE
============== running regression test queries ==============
test ltree ... ok
============== shutting down postmaster ==============
============== removing temporary installation ==============
=====================
All 1 tests passed.
=====================
另外一种测试时installcheck，和check不同的是，installcheck不需要初始化数据库，是在我们开启了数据库集群的情况下的测试。
同样的方法，我们可以发现它调用的是：
$(pg_regress_installcheck) $(REGRESS_OPTS) $(REGRESS)
通过src/Makefile.global的定义：
pg_regress_installcheck = $(top_builddir)/src/test/regress/pg_regress --inputdir=$(srcdir) --psqldir='$(PSQLDIR)' $(pg_regress_locale_flags) $(EXTRA_REGRESS_OPTS)
bindir := $(shell $(PG_CONFIG) --bindir)
以及
src/makefiles/pgxs.mk
PSQLDIR = $(bindir)
最终转换为：
../../src/test/regress/pg_regress --inputdir=. --psqldir='/opt/pgsql/bin' ltree
启动数据库后，就可以进行测试了。同样需要注意(PGPORT PGHOST PGDATABASE PGUSER等)环境变量。
postgres@digoal-> pg_ctl start
postgres@digoal-> pwd
/opt/soft_bak/postgresql-9.4.4/contrib/ltree
postgres@digoal-> ../../src/test/regress/pg_regress --inputdir=. --psqldir='/opt/pgsql/bin' ltree
(using postmaster on /data01/pg_root_1921, port 1921)
============== dropping database "regression" ==============
DROP DATABASE
============== creating database "regression" ==============
CREATE DATABASE
ALTER DATABASE
============== running regression test queries ==============
test ltree ... ok
=====================
All 1 tests passed.
=====================
所以插件的回归测试配置也很简单，同样需要sql, expected目录，以及通过配置Makefile来指定需要回归测试的sql脚本。
参考
1. http://www.postgresql.org/docs/devel/static/regress-run.html
2. http://www.postgresql.org/docs/devel/static/regress-variant.html
各种Makefile
src/Makefile.global
src/Makefile
src/makefiles/pgxs.mk
contrib/contrib-global.mk
contrib/xx/Makefile
......
代码覆盖率测试见我另一篇BLOG
http://blog.163.com/digoal@126/blog/static/1638770402015875295989/