On Mon, Apr 25, 2016 at 7:50 PM, David G. Johnston < david.g.johns...@gmail.com> wrote:
> On Monday, April 25, 2016, Melvin Davidson <melvin6...@gmail.com> wrote: > >> I need clarification on allow_system_table_mods parameter >> Per the documentation: >> *Allows modification of the structure of system tables.* This is used by >> initdb. This parameter can only be set at server start. >> >> However, attempting to modify pg_class to add another column fails with >> "STATUS_ACCESS_VIOLATION" as below. >> So either only certain system catalogs may be changed, or only certain >> types of structure changes are allowed. >> eg: add indexes, triggers >> >> Windows 10 >> PostgreSQL 9.2.15, compiled by Visual C++ build 1600, 32-bit >> >> Current user is postgres >> allow_system_table_mods = on >> >> ALTER TABLE pg_catalog.pg_class ADD COLUMN relcreated timestamp DEFAULT >> current_timestamp; >> >> Fails with: >> >> 2016-04-25 12:08:00 EDT STATEMENT: ALTER TABLE pg_catalog.pgclass ADD >> COLUMN relcreated timestamp DEFAULT current_timestamp; >> 2016-04-25 12:08:14 EDT LOG: server process (PID 7760) was terminated by >> exception 0xC0000005 >> 2016-04-25 12:08:14 EDT DETAIL: Failed process was running: ALTER TABLE >> pg_catalog.pg_class ADD COLUMN relcreated timestamp DEFAULT >> current_timestamp; >> 2016-04-25 12:08:14 EDT HINT: See C include file "ntstatus.h" for a >> description of the hexadecimal value. >> 2016-04-25 12:08:14 EDT LOG: terminating any other active server >> processes >> >> From ntstatus.h >> *#define STATUS_ACCESS_VIOLATION ((NTSTATUS)0xC0000005L) // >> winnt* >> >> > If it's going to prevent the action it should be able to do so without > crashing the server..and I doubt it's intended to be opinionated aside from > covering all DDL. What little there is on Google seems to support this. > > David J. > >I doubt it's intended to be opinionated aside from covering all DDL *So, IOW "* *Allows modification of the structure of system tables" does not allow ALTER TABLE ADD column on syscats? That seems a bit contradictory.* -- *Melvin Davidson* I reserve the right to fantasize. Whether or not you wish to share my fantasy is entirely up to you.
