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.
