Re: Proposal: knowing detail of config files via SQL

On 2/27/15 11:27 PM, Stephen Frost wrote:
>> >@@ -344,6 +346,21 @@ ProcessConfigFile(GucContext context)
>> > PGC_BACKEND, PGC_S_DYNAMIC_DEFAULT);
>> > }
>> >
>> >+ guc_file_variables = (ConfigFileVariable *)
>> >+ guc_malloc(FATAL, num_guc_file_variables * sizeof(struct ConfigFileVariable));
> Uh, perhaps I missed it, but what happens on a reload? Aren't we going
> to realloc this every time? Seems like we should be doing a
> guc_malloc() the first time through but doing guc_realloc() after, or
> we'll leak memory on every reload.
>
>> >+ /*
>> >+ * Apply guc config parameters to guc_file_variable
>> >+ */
>> >+ guc = guc_file_variables;
>> >+ for (item = head; item; item = item->next, guc++)
>> >+ {
>> >+ guc->name = guc_strdup(FATAL, item->name);
>> >+ guc->value = guc_strdup(FATAL, item->value);
>> >+ guc->filename = guc_strdup(FATAL, item->filename);
>> >+ guc->sourceline = item->sourceline;
>> >+ }
> Uh, ditto and double-down here. I don't see a great solution other than
> looping through the previous array and free'ing each of these, since we
> can't depend on the memory context machinery being up and ready at this
> point, as I recall.

MemoryContextInit() happens near the top of main(), before we call
InitializeGUCOptions(). So it should be possible to use memory contexts
here. I don't know why guc doesn't use palloc; perhaps for historical
reasons at this point?
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com