Re: Dynamically adding index types (was GIT indexes)

Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> We're able to dynamically add AMs in the way you suggest, but there is
> no way to alter the RMgrTable to either add a new RM or re-assign one of
> the unused RMs.

Hmmm...

> 1. Remove the "Const" in front of RmgrTable in rmgr.c. That would allow
> re-assignment of the two existing unused RMs.

Useless, as there's no way for an add-on AM to cause the value to be
changed before recovery begins.

> 2. Create a new catalog table pg_rm and some brief machinery to populate
> the RmgrTable from pg_rm. That would allow dynamically adding RMs.

Also useless --- what if pg_rm is damaged or missing? Even if it's
there, how would recovery be able to tell which rows are valid? We
certainly don't want it trying to do pg_clog probes.

regards, tom lane