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Add support for runtime arguments in injection points

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The macros INJECTION_POINT() and INJECTION_POINT_CACHED() are extended
with an optional argument that can be passed down to the callback
attached when an injection point is run, giving to callbacks the
possibility to manipulate a stack state given by the caller.  The
existing callbacks in modules injection_points and test_aio have their
declarations adjusted based on that.

da7226993f (core AIO infrastructure) and 93bc3d75d8 (test_aio) and
been relying on a set of workarounds where a static variable called
pgaio_inj_cur_handle is used as runtime argument in the injection point
callbacks used by the AIO tests, in combination with a TRY/CATCH block
to reset the argument value.  The infrastructure introduced in this
commit will be reused for the AIO tests, simplifying them.

Reviewed-by: Greg Burd <greg@burd.me>
Discussion: https://postgr.es/m/Z_y9TtnXubvYAApS@paquier.xyz
This commit is contained in:
Michael Paquier
2025-05-10 06:56:26 +09:00
parent 89372d0aaa
commit 371f2db8b0
23 changed files with 69 additions and 57 deletions
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16
doc/src/sgml/xfunc.sgml
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@ -3829,15 +3829,17 @@ uint32 WaitEventExtensionNew(const char *wait_event_name)
An injection point with a given <literal>name</literal> is declared using
macro:
<programlisting>
INJECTION_POINT(name);
INJECTION_POINT(name, arg);
</programlisting>
There are a few injection points already declared at strategic points
within the server code. After adding a new injection point the code needs
to be compiled in order for that injection point to be available in the
binary. Add-ins written in C-language can declare injection points in
their own code using the same macro. The injection point names should
use lower-case characters, with terms separated by dashes.
their own code using the same macro. The injection point names should use
lower-case characters, with terms separated by
dashes. <literal>arg</literal> is an optional argument value given to the
callback at run-time.
</para>
<para>
@ -3847,7 +3849,7 @@ INJECTION_POINT(name);
a two-step approach with the following macros:
<programlisting>
INJECTION_POINT_LOAD(name);
INJECTION_POINT_CACHED(name);
INJECTION_POINT_CACHED(name, arg);
</programlisting>
Before entering the critical section,
@ -3880,7 +3882,9 @@ extern void InjectionPointAttach(const char *name,
<literal>InjectionPointCallback</literal>:
<programlisting>
static void
custom_injection_callback(const char *name, const void *private_data)
custom_injection_callback(const char *name,
const void *private_data,
void *arg)
{
uint32 wait_event_info = WaitEventInjectionPointNew(name);
@ -3909,7 +3913,7 @@ if (IS_INJECTION_POINT_ATTACHED("before-foobar"))
local_var = 123;
/* also execute the callback */
INJECTION_POINT_CACHED("before-foobar");
INJECTION_POINT_CACHED("before-foobar", NULL);
}
#endif
</programlisting>