Documentation Source Text

Section {ATTACH DATABASE} attach {attached *ATTACH}

RecursiveBubbleDiagram attach-stmt
</tcl>

<p> ^The ATTACH DATABASE statement adds another database 
file to the current [database connection]. 
Database files that were previously attached can be removed using
the [DETACH DATABASE] command.

<p>^The filename for the database to be attached is the value of
the expression that occurs before the AS keyword.
^The filename of the database follows the same semantics as the
filename argument to [sqlite3_open()] and [sqlite3_open_v2()]; the
special name "[:memory:]" results in an [in-memory database] and an
empty string results in a new temporary database.
^The filename argument can be a [URI filename] if URI filename processing
is enable on the database connection.  The default behavior is for

    (Test coverage of the operating-system specific [VFSes] and extensions
    such as FTS and RTREE is less than 100%). </p></li>
</ul>

<p>TH3 was originally written for validation testing only, but has
subsequently been used for development testing and debugging
as well, and has proven very helpful in those roles.  A full-coverage
test takes less than five minutes on a workstation and hence
serves as a fast regression test during day-to-day maintenance
of the SQLite code base.</p>

<h2>2.0 Operation</h2>

<p>TH3 is a test program generator.  The output of TH3 is a program
implemented in C-code and intended to be
linked against the SQLite library under test.  The generated test
program is compiled and run on the target platform in order to verify
correct operation of SQLite on that platform.</p>

<p>The inputs to TH3 are test modules written in C or SQL and
small configuration
files that determine how to initialize SQLite.  The
TH3 package includes over eleven hundred test
modules and more than three dozen configuration files.
New modules and configurations
can be added to customize TH3 for specialized applications.
Each time TH3 is run, it reads
a subset of the available test modules and configuration files to generate
a custom C program that performs all of the specified tests under all
specified configurations.  A complete test of SQLite normally involves running
TH3 multiple times to generate multiple test programs covering different
aspects of SQLite's operation, then linking all test programs against
a common SQLite library and running them separately on the target platform.
SQLite will be found to work if all test programs pass.</p>

<p>There are no arbitrary limits in TH3.  One could generate a
single test program that contained all test modules and all configuration files.
However, such a test program might be too large to deploy on embedded
platforms.  Hence, TH3 provides the ability to break the library of test
modules up into smaller, more easily digested pieces.</p>

<p>Each individual test module might contain dozens, hundreds, or thousands
of separate tests.  The test modules can be written in C or as scripts of
SQL or a mixture of the two.  About two-thirds of the existing test modules are

<p>Once the test program is generated, it is run with no arguments to
perform the tests.  Progress information as well as error diagnostics
appear on standard output.  (Alternative output arrangements can be made
using a compile-time option for embedded devices that lack a standard
output channel.) The program returns zero if there are no
errors and non-zero if any problems were detected.</p>

<p>Typical output from a single TH3 test program run looks like this:

<blockquote><pre>
With SQLite 3.8.11 2015-05-15 04:13:15 56ef98a04765c34c1c2f3ed7a6f03a732f3b886e
-DSQLITE_COVERAGE_TEST
-DSQLITE_NO_SYNC
-DSQLITE_SYSTEM_MALLOC
-DSQLITE_THREADSAFE=1
Config-begin c1.
Begin c1.pager08
End c1.pager08
Begin c1.build33
End c1.build33
Begin c1.orderby01
End c1.orderby01
<i>... 15014 lines of output omitted ....</i>
Begin 64k.syscall01
End 64k.syscall01
Begin 64k.build01
End 64k.build01
Begin 64k.auth01
End 64k.auth01
Config-end 64k. TH3 memory used: 6373738
Config-begin wal1.
Begin wal1.wal37
End wal1.wal37
Config-end wal1. TH3 memory used: 100961
All 226 VDBE coverage points reached
th3: 0 errors out of 1442264 tests in 213.741 seconds. 64-bit little-endian
th3: SQLite 3.8.11 2015-05-15 04:13:15 56ef98a04765c34c1c2f3ed7a6f03a732f3b886e
</pre></blockquote>

<p>The output begins with a report of the [SQLITE_SOURCE_ID]
(cross-checked again [sqlite3_sourceid()]) for the
SQLite under test and the compile-time options used as reported
by [sqlite3_compileoption_get()].  The output concludes with a summary
of the test results and a repeat of the [SQLITE_SOURCE_ID].  If any
errors are detected, additional lines detail the problem.  The error
reporting lines always begin with a single space character so that they
can be quickly extracted from large output files using:

<blockquote><pre>
grep "&#94; "
</pre></blockquote>

<p>The default output shows the beginning and end of each configuration
and test module combination.  In the example above "c1" and "64k" are
configurations and "pager08", "build33", "orderby01", etc. are test modules.
Compile-time and run-time options are available to increase or decrease
the amount of output.
The output can be increased by showing each test case within each
test module.  The output can be decreased
by degrees: omitting test modules starts and stops,
omitting configuration starts and stops, and finally by omitting all output.
<h3>3.1 Test Automation Scripts</h3>

<p>TH3 comes with additional TCL scripts that help automate the testing
process on workstations.  The "th3make" script automatically runs "mkth3.tcl"
and "gcc" and then runs the resulting test program and checks the results.
Arguments to th3make include all of the "*.test" test modules and 
"*.cfg" configurations that are to be included in the test.  Additional
options to th3make can cause the test program to be compiled using different
compilers (GCC, Clang, MSVC), to use different output verbosity levels, to
run the test program under valgrind, to check the output for coverage using
gcov, and so forth.  The th3make script also accepts "*.rc" filenames as
arguments.  These *.rc files are just collections of other arguments that
are commonly used together for a single purpose.  For example, the "quick.rc"
file contains a set of eight arguments to th3make that run a fast (3-minute)
full-coverage test.  This allows the operator to type "./th3make quick.rc" as
a short-cut to typing out all of the required command-line options.  The
following are a few of the more than 40 available *.rc files:

<ul>
<li><b>alignment</b><i>N</i><b>.rc</b> - 
    These files contain -D options to the compiler that are used by
    various notable downstreams.
<li><b>cov.rc</b> - Options for measuring test coverage
<li><b>extensions.rc</b> - Options to enable [FTS4], [R-Trees],
    and [SQLITE_STAT4|STAT4].
<li><b>fast.rc</b> - Run mosts tests, including those not needed for
    coverage, skipping only soak tests, using delivery compiler options
    (ex: -O3)
<li><b>memdebug.rc</b> - like test.rc but also enable
    [SQLITE_MEMDEBUG|-DSQLITE_MEMDEBUG].
<li><b>min.rc</b> - Run the minimum set of tests needed for 100% coverage.
<li><b>quick.rc</b> - Run all tests required for 100% coverage tests
    using -Os and [SQLITE_DEBUG|-DSQLITE_DEBUG].
<li><b>test.rc</b> - Run the same tests as in fast.rc but without
    compiler optimization and enabling options like
    [SQLITE_DEBUG|-DSQLITE_DEBUG] and
    -DSQLITE_ENABLE_EXPENSIVE_ASSERT.
<li><b>test-ex.rc</b> - long-running soak tests.
</ul>

<p>The TH3 repository also includes the "multitest.tcl" script, another
TCL script used to automate TH3 testing on workstations.  Multitest.tcl
automatically compiles SQLite, then
runs ./th3make repeatedly with a variety of alignments, and captures
the output in a succinct summary screen.  A typical multitest.tcl run
generates output that looks like this:

<blockquote><pre>
file mkdir sqlite3bld
cd sqlite3bld
exec sh /home/drh/sqlite/sqlite/configure
file copy -force config.h ../config.h
exec make clean sqlite3.c
file rename sqlite3.c ../sqlite3.c
aa4f0f90c9c77424943e026a2ecee4a6c7f9e0d3  ../sqlite3.c
file rename sqlite3.h ../sqlite3.h
exec make clean sqlite3.c OPTS=-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT=1
file rename sqlite3.c ../sqlite3udl.c
0d3bbc92c433f940253bb2c7c19de7783133929d  ../sqlite3udl.c
exec make clean sqlite3.c OPTS=-DSQLITE_SMALL_STACK=1
file rename sqlite3.c ../sqlite3ss.c
fcf6963e94096324461076d3b9e9dc1888e066e1  ../sqlite3ss.c
cd ..
*******************************************************************************
t01: quick.rc.................................................. Ok   (00:04:00)
t02: cov.rc.................................................... Ok   (00:04:40)
t03: quick.rc extensions.rc -D_HAVE_SQLITE_CONFIG_H............ Ok   (00:05:22)
t04: cov.rc -DSQLITE_ENABLE_STAT4 -D_HAVE_SQLITE_CONFIG_H...... Ok   (00:05:20)
t05: test.rc ../th3private/*.test.............................. Ok   (00:00:17)
t06: test.rc ../th3private/*.test -DSQLITE_ENABLE_STAT4........ Ok   (00:00:43)
t07: quick.rc -DSQLITE_TEST_REALLOC_STRESS -funsigned-char..... Ok   (00:04:56)
t08: quick.rc -DSQLITE_THREADSAFE=0 -fsigned-char.............. Ok   (00:03:12)
t09: quick.rc sqlite3ss.c -DSQLITE_MAX_ATTACHED=125............ Ok   (00:04:04)
t10: quick.rc -DSQLITE_RUNTIME_BYTEORDER....................... Ok   (00:03:58)
t11: quick.rc -DSQLITE_DIRECT_OVERFLOW_READ.................... Ok   (00:04:01)
t12: fast.rc................................................... Ok   (00:14:19)
t13: fast.rc alignment1.rc -m32................................ Ok   (00:20:51)
t14: fast.rc alignment2.rc sqlite3udl.c........................ Ok   (00:16:06)
t15: fast.rc alignment4.rc..................................... Ok   (00:12:55)
t16: fast.rc alignment5.rc..................................... Ok   (00:14:58)
t17: fast.rc alignment6.rc..................................... Ok   (00:14:31)
t18: fast.rc alignment7.rc..................................... Ok   (00:16:06)
t19: fast.rc alignment8.rc sqlite3udl.c........................ Ok   (00:24:09)
t20: test.rc alignment1.rc..................................... Ok   (00:49:27)
t21: test.rc alignment2.rc sqlite3udl.c........................ Ok   (00:38:43)
t22: test.rc alignment4.rc -m32 CC=clang....................... Ok   (00:39:49)
t23: test.rc alignment5.rc..................................... Ok   (00:36:33)
t24: test.rc alignment6.rc..................................... Ok   (00:33:53)
t25: test.rc alignment7.rc..................................... Ok   (00:42:16)
t26: test.rc alignment8.rc sqlite3udl.c........................ Ok   (01:05:22)
t27: memdebug.rc extensions.rc................................. Ok   (01:35:56)
t28: fast.rc -fsanitize=undefined.............................. Ok   (00:15:09)
t29: min.rc -O3 -valgrind...................................... Ok   (01:26:10)
t30: min.rc -O3 -valgrind extensions.rc........................ Ok   (01:47:12)
t31: test-ex.rc................................................ Ok   (03:20:18)
*******************************************************************************
0 failures on 31 th3make runs and 166721387 tests in (16:25:29)
SQLite 3.8.10 2015-05-05 18:52:54 04afa3febee32854fbb09ef8d4ffffd432119716
</pre></blockquote>

<p>As can be seen above, a single run
of multitest.tcl invokes th3make dozens times and takes between 12 and 24
hours.  The middle section of the output shows the arguments to each individual
th3make run and the result and elapse time for that th3make.
All build products and output for the separate th3make runs are
captures in subdirectories for post-test analysis.
The two-line summary at the bottom shows the total number of errors and tests
over all th3make runs and the total elapse time, together with the 
[SQLITE_SOURCE_ID] information for the version of SQLite that was
tested.  This summary information is recorded in the
<a href="https://www.sqlite.org/checklists/3081000/index#c6">release
checklist</a> during testing.

<h2>4.0 Test Coverage</h2>

<p>Using one particular subset of the available TH3 test modules (the "cov1"
tests) SQLite obtained 
[test coverage | 100% branch test coverage] and 100% [MC/DC] as measured
by [http://gcc.gnu.org/onlinedocs/gcc/Gcov.html | gcov]