Move SLRU_PAGES_PER_SEGMENT to pg_config_manual.h

It seems plausible that someone might want to experiment with
different values. The pressing reason though is that I'm reviewing a
patch that requires pg_upgrade to manipulate SLRU files. That patch
needs to access SLRU_PAGES_PER_SEGMENT from pg_upgrade code, and
slru.h, where SLRU_PAGES_PER_SEGMENT is currently defined, cannot be
included from frontend code. Moving it to pg_config_manual.h makes it
accessible.

Now that it's a little more likely that someone might change
SLRU_PAGES_PER_SEGMENT, add a cluster compatibility check for it.

Bump catalog version because of the new field in the control file.

Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Discussion: https://www.postgresql.org/message-id/c7a4ea90-9f7b-4953-81be-b3fcb47db057@iki.fi

0 files changed, 0 insertions, 0 deletions