Add some new items and some additional details to existing items, mostly
by cribbing from the 9.1alpha notes. Some additional clarifications and
corrections elsewhere, and a few typo fixes.
On closer inspection, that two-element initcond value seems to have been
a little white lie to avoid explaining the full behavior of float8_accum.
But if people are going to expect the examples to be exactly correct,
I suppose we'd better explain. Per comment from Thom Brown.
Install just one instance of the "C" and "POSIX" collations into
pg_collation, rather than one per encoding. Make these instances exist
and do something useful even in machines without locale_t support: to wit,
it's now possible to force comparisons and case-folding functions to use C
locale in an otherwise non-C database, whether or not the platform has
support for using any additional collations.
Fix up severely broken upper/lower/initcap functions, too: the C/POSIX
fastpath now does what it is supposed to, and non-default collations are
handled correctly in single-byte database encodings.
Merge the two separate collation hashtables that were being maintained in
pg_locale.c, and be more wary of the possibility that we fail partway
through filling a cache entry.
This removes an overloading of two authentication options where
one is very secure (peer) and one is often insecure (ident). Peer
is also the name used in libpq from 9.1 to specify the same type
of authentication.
Also make initdb select peer for local connections when ident is
chosen, and ident for TCP connections when peer is chosen.
ident keyword in pg_hba.conf is still accepted and maps to peer
authentication.
1. Don't ignore query cancel interrupts. Instead, if the user asks to
cancel the query after we've already committed it, but before it's on
the standby, just emit a warning and let the COMMIT finish.
2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown).
Instead, emit a warning message and close the connection without
acknowledging the commit. Other backends will still see the effect of
the commit, but there's no getting around that; it's too late to abort
at this point, and ignoring die interrupts altogether doesn't seem like
a good idea.
3. If synchronous_standby_names becomes empty, wake up all backends
waiting for synchronous replication to complete. Without this, someone
attempting to shut synchronous replication off could easily wedge the
entire system instead.
4. Avoid depending on the assumption that if a walsender updates
MyProc->syncRepState, we'll see the change even if we read it without
holding the lock. The window for this appears to be quite narrow (and
probably doesn't exist at all on machines with strong memory ordering)
but protecting against it is practically free, so do that.
5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and
doesn't actually do anything.
There's still some further work needed here to make the behavior of fast
shutdown plausible, but that looks complex, so I'm leaving it for a
separate commit. Review by Fujii Masao.
- Make the name of the ID tag for the GUC entry match the GUC name.
- Clarify that synchronous_replication waits for xlog flush, not receipt.
- Mention that synchronous_replication won't wait if max_wal_senders=0.
Use collencoding = -1 to represent such a collation in pg_collation.
We need this to make the "default" entry work sanely, and a later
patch will fix the C/POSIX entries to be represented this way instead
of duplicating them across all encodings. All lookup operations now
search first for an entry that's database-encoding-specific, and then
for the same name with collencoding = -1.
Also some incidental code cleanup in collationcmds.c and pg_collation.c.
Removes extraneous closing parenthesis from pg_describe_object
Puts pg_describe_object and has_sequence_privilege in correct
alphabetical position in function listing
Thom Brown
