9 Commits (ecacbdbcee67e202cfcaa1180da170b9f13654bb)

Author	SHA1	Message	Date
Bruce Momjian	7ec73783d8	copy: update docs for FORCE_NULL and FORCE_NOT_NULL combination ... Also update regression tests Patch by Michael Paquier	12 years ago
Andrew Dunstan	3b5e03dca2	Provide a FORCE NULL option to COPY in CSV mode. ... This forces an input field containing the quoted null string to be returned as a NULL. Without this option, only unquoted null strings behave this way. This helps where some CSV producers insist on quoting every field, whether or not it is needed. The option takes a list of fields, and only applies to those columns. There is an equivalent column-level option added to file_fdw. Ian Barwick, with some tweaking by Andrew Dunstan, reviewed by Payal Singh.	12 years ago
Tom Lane	21734d2fb8	Support writable foreign tables. ... This patch adds the core-system infrastructure needed to support updates on foreign tables, and extends contrib/postgres_fdw to allow updates against remote Postgres servers. There's still a great deal of room for improvement in optimization of remote updates, but at least there's basic functionality there now. KaiGai Kohei, reviewed by Alexander Korotkov and Laurenz Albe, and rather heavily revised by Tom Lane.	13 years ago
Alvaro Herrera	cb9b66d31a	Improve error message wording ... The wording changes applied in 0ac5ad513 were universally disliked. Per gripe from Andrew Dunstan	13 years ago
Alvaro Herrera	0ac5ad5134	Improve concurrency of foreign key locking ... This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov	13 years ago
Peter Eisentraut	8402fab411	file_fdw: Improve error message ... The hint looked a bit confusing when there were no valid options to hint about.	14 years ago
Tom Lane	86a3f2d492	Add FORCE_NOT_NULL support to the file_fdw foreign data wrapper. ... This is implemented as a per-column boolean option, rather than trying to match COPY's convention of a single option listing the column names. Shigeru Hanada, reviewed by KaiGai Kohei	14 years ago
Tom Lane	6e6cc5910b	Make the file_fdw validator check that a filename option has been provided. ... This was already a runtime failure condition, but it's better to check at validation time if possible. Lightly modified version of a patch by Shigeru Hanada.	15 years ago
Tom Lane	7c5d0ae707	Add contrib/file_fdw foreign-data wrapper for reading files via COPY. ... This is both very useful in its own right, and an important test case for the core FDW support. This commit includes a small refactoring of copy.c to expose its option checking code as a separately callable function. The original patch submission duplicated hundreds of lines of that code, which seemed pretty unmaintainable. Shigeru Hanada, reviewed by Itagaki Takahiro and Tom Lane	15 years ago