pg_stat_statements and preloading extensions

[samwillis]

pg_stat_statements Is currently built but we don't yet have a way to preload it. There are a few extensions that needed this facility and this is a very popular one.

https://www.postgresql.org/docs/current/pgstatstatements.html

The module must be loaded by adding pg_stat_statements to shared_preload_libraries in postgresql.conf, because it requires additional shared memory.

[pmp-p]

maybe we could add pg_stat_statements to GUC shared_preload_libraries_string global variable and manually call process_shared_preload_libraries right after wasm compilation. But PGlite options extensions should allow to specify the extension need to be added ( or maybe we can detect that when parsing imported symbol and make a hitlist ).

[pmp-p]

after reflexion, we are always preloading all plugin shared lib, pg core just doesn't know it. so we just have to tell it by setting process_shared_preload_libraries_in_progress to true while wasm compilation of plugins

edit/ but PG_init constructor is not called at that time, and some extensions don't want to be pg_init that early

[pmp-p]

shared_preload_libraries it must be set in the .conf right after initdb or shared_preload_libraries_string string will be blanked by guc tables init.

libraries will be processed whatever mode we start https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=6c31ac091f31171601ee00972e131d8683e7b828