Re: Support worker_spi to execute the function dynamically.

Hi,

On 2023-07-20 13:50, Bharath Rupireddy wrote:
> On Thu, Jul 20, 2023 at 10:09 AM Michael Paquier <michael@paquier.xyz> 
> wrote:
>> 
>> On Thu, Jul 20, 2023 at 09:43:37AM +0530, Bharath Rupireddy wrote:
>> > +1. However, a comment above helps one to understand why some GUCs are
>> > defined before if (!process_shared_preload_libraries_in_progress). As
>> > this is an example extension, it will help understand the reasoning
>> > better. I know we will it in the commit message, but a direct comment
>> > helps:
>> >
>> >     /*
>> >      * Note that this GUC is defined irrespective of worker_spi shared library
>> >      * presence in shared_preload_libraries. It's possible to create the
>> >      * worker_spi extension and use functions without it being specified in
>> >      * shared_preload_libraries. If we return from here without defining this
>> >      * GUC, the dynamic workers launched by worker_spi_launch() will keep
>> >      * crashing and restarting.
>> >      */
>> 
>> WFM to be more talkative here and document things, but I don't think
>> that's it.  How about a simple "These GUCs are defined even if this
>> library is not loaded with shared_preload_libraries, for
>> worker_spi_launch()."
> 
> LGTM.

Thanks for discussing about the patch. I updated the patch from your 
comments
* v2-0001-Support-worker_spi-to-execute-the-function-dynamical.patch

I found another thing to be changed better. Though the tests was assumed
"shared_preload_libraries = worker_spi", the background workers failed 
to
be launched in initialized phase because the database is not created 
yet.

```
# make check    # in src/test/modules/worker_spi
# cat log/postmaster.log # in src/test/modules/worker_spi/
2023-07-20 17:58:47.958 JST worker_spi[853620] FATAL:  database 
"contrib_regression" does not exist
2023-07-20 17:58:47.958 JST worker_spi[853621] FATAL:  database 
"contrib_regression" does not exist
2023-07-20 17:58:47.959 JST postmaster[853612] LOG:  background worker 
"worker_spi" (PID 853620) exited with exit code 1
2023-07-20 17:58:47.959 JST postmaster[853612] LOG:  background worker 
"worker_spi" (PID 853621) exited with exit code 1
```

It's better to remove "shared_preload_libraries = worker_spi" from the
test configuration. I misunderstood that two background workers would
be launched and waiting at the start of the test.

Regards,
-- 
Masahiro Ikeda
NTT DATA CORPORATION