Add support for coordinating record typmods among parallel workers. Tuples can have type RECORDOID and a typmod number that identifies a blessed TupleDesc in a backend-private cache. To support the sharing of such tuples through shared memory and temporary files, provide a typmod registry in shared memory.
To achieve that, introduce per-session DSM segments, created on demand when a backend first runs a parallel query. The per-session DSM segment has a table-of-contents just like the per-query DSM segment, and initially the contents are a shared record typmod registry and a DSA area to provide the space it needs to grow. State relating to the current session is accessed via a Session object reached through global variable CurrentSession that may require significant redesign further down the road as we figure out what else needs to be shared or remodelled. Author: Thomas Munro Reviewed-By: Andres Freund Discussion: https://postgr.es/m/CAEepm=0ZtQ-SpsgCyzzYpsXS6e=kzwqk3g5ygn3mdv7a8da...@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/cc5f81366c36b3dd8f02bd9be1cf75b2cc8482bd Modified Files -------------- src/backend/access/common/Makefile | 2 +- src/backend/access/common/session.c | 208 +++++++++++ src/backend/access/common/tupdesc.c | 16 + src/backend/access/transam/parallel.c | 44 ++- src/backend/storage/lmgr/lwlock.c | 8 +- src/backend/utils/cache/typcache.c | 634 ++++++++++++++++++++++++++++++++-- src/backend/utils/init/postinit.c | 4 + src/include/access/session.h | 44 +++ src/include/access/tupdesc.h | 6 + src/include/storage/lwlock.h | 3 + src/include/utils/typcache.h | 10 + src/tools/pgindent/typedefs.list | 4 + 12 files changed, 946 insertions(+), 37 deletions(-) -- Sent via pgsql-committers mailing list (pgsql-committers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers
