Grant Limberg wrote: > I've got InnoDB 1.0.1 compiling with no warnings now. Now I just have > to make it actually work! As of right now, drizzle is reporting the > following when starting up for make test: > > 080826 5:43:39 [ERROR] Unknown/unsupported table type: innodb > 080826 5:43:39 [ERROR] Aborting > > So it's obviously not quite working as expected yet. I've attempted to > ./configure the project with --with-debug but that causes a linker error > in sql_derived.cc (see the bug report: > https://bugs.launchpad.net/drizzle/+bug/261687). Once I have that > fixed, I do have a question. How does one go about debugging this?
The easiest way is to use GDB. Run the server within a GDB session and
step through the code using GDB step/next/continue/break commands.
To use GDB, this is what I typically do...
Build the server with debugging symbols (--enable-debug) into /tmp using
the attached script, then:
cd /tmp/mybranch/tests
./dtr --start-and-exit --gdb
This will pop open a GDB instance for the server process, and it is
waiting for client connections...so let's go ahead and create one:
Switch back to your terminal and do:
cd /tmp/mybranch/client
./drizzle --user=root --port=9306
You will notice that the client seems to just "hang". Switch back the
GDB session you have open for the server and you will notice that GDB
(actually the test suite...) has set a breakpoint at the mysql_parse()
function. You'll see something like this:
[Switching to Thread 0xb317fb90 (LWP 11710)]
Breakpoint 1, mysql_parse (thd=0x8878c18),
inBuf=0x8882290 "select @@version_comment limit 1", length=32,
found_semicolon=0xb317f040) at sql_parse.cc:2870
2870 const char ** found_semicolon)
(gdb)
The above is basically showing you the function call stack and argument
addresses being passed to the mysql_parse() function, located in
drizzled/sql_parse.cc at line 2870.
To see the full call stack, do:
(gdb) where
You'll see that the call stack goes from the thread scheduler
(libevent_thread_proc()) to the parser (do_command(), then
dispatch_command(), then mysql_parse()).
To step into the server process, do:
(gdb) step
This will run to the next function call. Simply hit enter to repeat the
step. To see what a variable contains at any time, simple do:
(gdb) print name_of_variable
For instance, if I do:
(gdb) print thd
I get:
$1 = (class THD*) 0x8878c18
I can also grab a pointer's member variables, such as the thread's
current query ID:
(gdb) print thd->query_id
$2 = 1
And so on...
You can set another break point (for instance, a function you are
interested in) by doing:
(gdb) break function_name
for instance, if I look through the source code, I see that once a
SELECT query is issued by the client, the function mysql_select() is
called, so I could do:
(gdb) break mysql_select
GDB will inform you a breakpoint has been set, and the line number of
the file, like so:
Breakpoint 2 at 0x814ea09: file sql_select.cc, line 2618.
To continue until that breakpoint, do:
(gdb) continue
And you are now at mysql_select()...
If you continue again, and you switch back to your terminal with the
drizzle client in it. You should see a drizzle client at the command
prompt, like so:
[EMAIL PROTECTED]: /tmp/trunk/client]$ ./drizzle --user=root
--port=9306
Welcome to the Drizzle client.. Commands end with ; or \g.
Your Drizzle connection id is 1
Server version: 7.0.0-log Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
drizzle>>
Keep this client open, since you will be executing commands through it.
In the GDB session, type:
(gdb) break mysql_parse
(gdb) continue
Then the client, do:
drizzle>> SELECT * FROM INFORMATION_SCHEMA.TABLES;
and switch back to the server GDB session. You will see that GDB has
broken once more at mysql_parse() and that the inBuf is the "SELECT *
FROM INFORMATION_SCHEMA.TABLES" you just sent it...
I'll let you play around with GDB and see what else it can do. :)
Cheers, and hope this gets you on your way at least,
Jay
build_and_test.sh
Description: Bourne shell script
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