There was a race condition where the receiving pipe could be closed by the
child thread if the main thread was pre-empted before it got a chance to
create a new one, and the dispatch thread ran to completion during that time.
One symptom of this is that rows in pg_listener could be dropped under
heavy load.
Analysis and original patch by Radu Ilie, with some small
modifications by Magnus Hagander.
Since all current and foreseeable future command tags will be pure ASCII,
there is no need to do conversion on them. This saves a few cycles and also
avoids polluting otherwise-pristine subtransaction memory contexts, which
is the cause of the backend memory leak exhibited in bug #5302. (Someday
we'll probably want to have a better method of determining whether
subtransaction contexts need to be kept around, but today is not that day.)
Backpatch to 8.0. The cycle-shaving aspect of this would work in 7.4
too, but without subtransactions the memory-leak aspect doesn't apply,
so it doesn't seem worth touching 7.4.
false positives during Hot Standby conflict processing. Simple
patch to enhance conflict processing, following previous discussions.
Controlled by parameter minimize_standby_conflicts = on | off, with
default off allows measurement of performance impact to see whether
it should be set on all the time.
records for heap and btree. Minor change, mostly API changes to
pass through the required values. This is a simple change though
also provides the refactoring required for further enhancements
to conflict processing using the relOid. Changes only have effect
during Hot Standby.
LogwrtRqst.Write can be set to non-existent FF log segment, we mustn't
try to send that in XLogSend().
Also fix similar bug in ReadRecord(), which I just introduced in the
ReadRecord() refactoring patch.
restore_command, if the connection to the primary server is lost. This
ensures that the standby can recover automatically, if the connection is
lost for a long time and standby falls behind so much that the required
WAL segments have been archived and deleted in the master.
This also makes standby_mode useful without streaming replication; the
server will keep retrying restore_command every few seconds until the
trigger file is found. That's the same basic functionality pg_standby
offers, but without the bells and whistles.
To implement that, refactor the ReadRecord/FetchRecord functions. The
FetchRecord() function introduced in the original streaming replication
patch is removed, and all the retry logic is now in a new function called
XLogReadPage(). XLogReadPage() is now responsible for executing
restore_command, launching walreceiver, and waiting for new WAL to arrive
from primary, as required.
This also changes the life cycle of walreceiver. When launched, it now only
tries to connect to the master once, and exits if the connection fails, or
is lost during streaming for any reason. The startup process detects the
death, and re-launches walreceiver if necessary.
default of "plpgsql". This is more reasonable than it was when the DO patch
was written, because we have since decided that plpgsql should be installed
by default. Per discussion, having a parameter for this doesn't seem useful
enough to justify the risk of application breakage if the value is changed
unexpectedly.
These files have apparently been edited over the years by a dozen people
with as many different editor settings, which made the alignment of the
paragraphs quite inconsistent and ugly. I made a pass of M-q with Emacs
to straighten it out.
and implement OVERLAY() for bit strings and bytea.
In passing also convert text OVERLAY() to a true built-in, instead of
relying on a SQL function.
Leonardo F, reviewed by Kevin Grittner
AbortTransaction or AbortSubTransaction, when trying to clean up after an
error that prevented (sub)transaction start from completing:
* access to TopTransactionResourceOwner that might not exist
* assert failure in AtEOXact_GUC, if AtStart_GUC not called yet
* assert failure or core dump in AfterTriggerEndSubXact, if
AfterTriggerBeginSubXact not called yet
Per testing by injecting elog(ERROR) at successive steps in StartTransaction
and StartSubTransaction. It's not clear whether all of these cases could
really occur in the field, but at least one of them is easily exposed by
simple stress testing, as per my accidental discovery yesterday.
the various disk-size-reporting functions will respond to query cancel
reasonably promptly even in very large databases. Per report from
Kevin Grittner.
woken by alarm we send SIGUSR1 to all backends requesting that they
check to see if they are blocking Startup process. If so, they throw
ERROR/FATAL as for other conflict resolutions. Deadlock stop gap
removed. max_standby_delay = -1 option removed to prevent deadlock.
Attributes can now have options, just as relations and tablespaces do, and
the reloptions code is used to parse, validate, and store them. For
simplicity and because these options are not performance critical, we store
them in a separate cache rather than the main relcache.
Thanks to Alex Hunsaker for the review.
Discuss the reasons for the lock type we hold on ProcArrayLock while deriving
the conflict list. Cover the idea of false positive conflicts and seemingly
strange effects on snapshot derivation.
that would've been WAL-logged if archiving was enabled. If we encounter
such records in archive recovery anyway, we know that some data is
missing from the log. A WARNING is emitted in that case.
Original patch by Fujii Masao, with changes by me.
walreceiver as whole into a dynamically loaded module, split the
libpq-specific parts of it into dynamically loaded module and keep the rest
in the main backend binary.
Although Tom fixed the Windows compilation problems with the old walreceiver
module already, this is a cleaner division of labour and makes the code
more readable. There's also the prospect of adding new transport methods
as pluggable modules in the future, which this patch makes easier, though for
now the API between libpqwalreceiver and walreceiver process should be
considered private.
The libpq-specific module is now in src/backend/replication/libpqwalreceiver,
and the part linked with postgres binary is in
src/backend/replication/walreceiver.c.
name already exists, so we'd get an error message about a "type" instead
of about a "relation", because the composite type code shares code with
relation creation.
when the planner splits apart a ROW(...) IS NULL test, the argisrow values
of the component tests have to be determined from the component field types,
not copied from the original NullTest (in which argisrow is surely true).
EXISTS that contains a WITH clause. This would usually lead to a
"could not find CTE" error later in planning, because the WITH wouldn't
get processed at all. Noted while playing with an example from Ken Marshall.
after it's released its reference count for the cached plan. There are
code paths that might try to examine the plan list before noticing that
the portal is already in aborted state. Report and diagnosis by Tatsuo
Ishii, though this isn't exactly his proposed patch.
pg_constraint before searching pg_trigger. This allows saner handling of
corner cases; in particular we now say "constraint is not deferrable"
rather than "constraint does not exist" when the command is applied to
a constraint that's inherently non-deferrable. Per a gripe several months
ago from hubert depesz lubaczewski.
To make this work without breaking user-defined constraint triggers,
we have to add entries for them to pg_constraint. However, in return
we can remove the pgconstrname column from pg_constraint, which represents
a fairly sizable space savings. I also replaced the tgisconstraint column
with tgisinternal; the old meaning of tgisconstraint can now be had by
testing for nonzero tgconstraint, while there is no other way to get
the old meaning of nonzero tgconstraint, namely that the trigger was
internally generated rather than being user-created.
In passing, fix an old misstatement in the docs and comments, namely that
pg_trigger.tgdeferrable is exactly redundant with pg_constraint.condeferrable.
Actually, we mark RI action triggers as nondeferrable even when they belong to
a nominally deferrable FK constraint. The SET CONSTRAINTS code now relies on
that instead of hard-coding a list of exception OIDs.
against concurrent reconnection. Failure during testing showed issue
was possible, even though earlier analysis seemed to indicate it
would not be required. Use LockSharedObjectForSession() before
ResolveRecoveryConflictWithDatabase() and hold lock until end of
processing for that WAL record. Simple approach to avoid introducing
further bugs at this stage of development on an improbable issue.
Conflict reason is passed through directly to the backend, so we can
take decisions about the effect of the conflict based upon the local
state. No specific changes, as yet, though this prepares for later work.
CancelVirtualTransaction() sends signals while holding ProcArrayLock.
Introduce errdetail_abort() to give message detail explaining that the
abort was caused by conflict processing. Remove CONFLICT_MODE states
in favour of using PROCSIG_RECOVERY_CONFLICT states directly, for clarity.
parse analysis phase, rather than at execution time. This makes parameter
handling work the same as it does in ordinary plannable queries, and in
particular fixes the incompatibility that Pavel pointed out with plpgsql's
new handling of variable references. plancache.c gets a little bit
grottier, but the alternatives seem worse.
This includes two new kinds of postmaster processes, walsenders and
walreceiver. Walreceiver is responsible for connecting to the primary server
and streaming WAL to disk, while walsender runs in the primary server and
streams WAL from disk to the client.
Documentation still needs work, but the basics are there. We will probably
pull the replication section to a new chapter later on, as well as the
sections describing file-based replication. But let's do that as a separate
patch, so that it's easier to see what has been added/changed. This patch
also adds a new section to the chapter about FE/BE protocol, documenting the
protocol used by walsender/walreceivxer.
Bump catalog version because of two new functions,
pg_last_xlog_receive_location() and pg_last_xlog_replay_location(), for
monitoring the progress of replication.
Fujii Masao, with additional hacking by me
of this are to centralise the conflict code to allow further change,
as well as to allow passing through the full reason for the conflict
through to the conflicting backends. Backend state alters how we
can handle different types of conflict so this is now required.
As originally suggested by Heikki, no longer optional.
underlying catalog not only the index itself. Otherwise, if the cache
load process touches the catalog (which will happen for many though not
all of these indexes), we are locking index before parent table, which can
result in a deadlock against processes that are trying to lock them in the
normal order. Per today's failure on buildfarm member gothic_moth; it's
surprising the problem hadn't been identified before.
Back-patch to 8.2. Earlier releases didn't have the issue because they
didn't try to lock these indexes during load (instead assuming that they
couldn't change schema at all during multiuser operation).
especially not ROLLBACK. ROLLBACK might need to be executed in an already
aborted transaction, when there is no safe way to revalidate the plan. But
in general there's no point in marking utility statements invalid, since
they have no plans in the normal sense of the word; so we might as well
work a bit harder here to avoid future revalidation cycles.
Back-patch to 8.4, where the bug was introduced.
in the parameter array. Noted while experimenting with an example
from Pavel. This wouldn't come up in normal use, but it ought to honor
the specification that a parameter array can have unused slots.
occurring during a reload, such as query-cancel. Instead of zeroing out
an existing relcache entry and rebuilding it in place, build a new relcache
entry, then swap its contents with the old one, then free the new entry.
This avoids problems with code believing that a previously obtained pointer
to a cache entry must still reference a valid entry, as seen in recent
failures on buildfarm member jaguar. (jaguar is using CLOBBER_CACHE_ALWAYS
which raises the probability of failure substantially, but the problem
could occur in the field without that.) The previous design was okay
when it was made, but subtransactions and the ResourceOwner mechanism
make it unsafe now.
Also, make more use of the already existing rd_isvalid flag, so that we
remember that the entry requires rebuilding even if the first attempt fails.
Back-patch as far as 8.2. Prior versions have enough issues around relcache
reload anyway (due to inadequate locking) that fixing this one doesn't seem
worthwhile.
can upgrade clusters without renaming the tablespace directories. New
directory structure format is, e.g.:
$PGDATA/pg_tblspc/20981/PG_8.5_201001061/719849/83292814
rowtype contains dropped columns. Sometimes the input tuple will be formed
from a select targetlist in which dropped columns are filled with a NULL
of an arbitrary type (the planner typically uses INT4, since it can't tell
what type the dropped column really was). So we need to relax the rowtype
compatibility check to not insist on physical compatibility if the actual
column value is NULL.
In principle we might need to do this for functions returning composite
types, too (see tupledesc_match()). In practice there doesn't seem to be
a bug there, probably because the function will be using the same cached
rowtype descriptor as the caller. Fixing that code path would require
significant rearrangement, so I left it alone for now.
Per complaint from Filip Rembialkowski.
Previously we only cancelled sessions that were in-transaction.
Simple fix is to just cancel all sessions without waiting. Doing
it this way avoids complicating common code paths, which would
not be worth the trouble to cover this rare case.
Problem report and fix by Andres Freund, edited somewhat by me
This silences some warnings on Win64. Not using the proper SOCKET datatype
was actually wrong on Win32 as well, but didn't cause any warnings there.
Also create define PGINVALID_SOCKET to indicate an invalid/non-existing
socket, instead of using a hardcoded -1 value.
Previously, fastgetattr() and heap_getattr() tested their fourth argument
against a null pointer, but any attempt to use them with a literal-NULL
fourth argument evaluated to *(void *)0, resulting in a compiler error.
Remove these NULL tests to avoid leading future readers of this code to
believe that this has a chance of working. Also clean up related legacy
code in nocachegetattr(), heap_getsysattr(), and nocache_index_getattr().
The new coding standard is that any code which calls a getattr-type
function or macro which takes an isnull argument MUST pass a valid
boolean pointer. Per discussion with Bruce Momjian, Tom Lane, Alvaro
Herrera.
extract a system column, and remove a couple of lines that are useless
in light of the fact that we aren't ever going to support this case. There
isn't much point in trying to make this work because a tuple Datum does
not carry many of the system columns. Per experimentation with a case
reported by Dean Rasheed; we'll have to fix his problem somewhere else.
deletion, so that we attempt to unlink the correct filepath. unlink()
errors are ignorable there, so lack of a DatabasePath initialization step
did not cause visible problems until a related bug showed up on Solaris.
Code refactored from xact_redo_commit() to
ProcessCommittedInvalidationMessages() in inval.c. Recovery may replay
shared invalidation messages for many databases, so we cannot
SetDatabasePath() once as we do in normal backends. Read the databaseid
from the shared invalidation messages, then set DatabasePath
temporarily before calling RelationCacheInitFileInvalidate().
Problem report by Robert Treat, analysis and fix by me.
someone else has just updated it, we have to set priorXmax to that tuple's
xmax (ie, the XID of the other xact that updated it) before looping back to
examine the next tuple. Obviously, the next tuple in the update chain should
have that XID as its xmin, not the same xmin as the preceding tuple that we
had been trying to lock. The mismatch would cause the EvalPlanQual logic to
decide that the tuple chain ended in a deletion, when actually there was a
live tuple that should have been found.
I inserted this error when recently adding logic to EvalPlanQual to make it
lock tuples before returning them (as opposed to the old method in which the
lock would occur much later, causing a great deal of work to be wasted if we
only then discover someone else updated it). Sigh. Per today's report from
Takahiro Itagaki of inconsistent results during pgbench runs.
of the string". The previous coding treated only -1 that way, and would
produce an invalid result value for other negative values.
We ought to fix it so that 2-parameter bit substring() is a different C
function and the 3-parameter form throws error for negative length, but
that takes a pg_proc change which is impractical in the back branches;
and in any case somebody might be relying on -1 working this way.
So just do this as a back-patchable fix.
It is absolutely not okay to throw an ereport(ERROR) in any random place in
the code just because DoingCommandRead is set; interrupting, say, OpenSSL
in the midst of its activities is guaranteed to result in heartache.
Instead of that, undo the original optimizations that threw away
QueryCancelPending anytime we were starting or finishing a command read, and
instead discard the cancel request within ProcessInterrupts if we find that
there is no HS reason for forcing a cancel and we are DoingCommandRead.
In passing, may I once again condemn the practice of changing the code
and not fixing the adjacent comment that you just turned into a lie?
we're not going to support that anymore.
I did keep the 64-bit-CRC-with-32-bit-arithmetic code, since it has a
performance excuse to live. It's a bit moot since that's all ifdef'd
out, of course.
Add missing varlena header to TableSpaceOpts structure. And, per
Tom Lane, instead of calling tablespace_reloptions in CacheMemoryContext,
call it in the caller's memory context and copy the value over
afterwards, to reduce the chances of a session-lifetime memory leak.
VACUUM FULL was renamed to VACUUM FULL INPLACE. Also added a new
option -i, --inplace for vacuumdb to perform FULL INPLACE vacuuming.
Since the new VACUUM FULL uses CLUSTER infrastructure, we cannot
use it for system tables. VACUUM FULL for system tables always
fall back into VACUUM FULL INPLACE silently.
Itagaki Takahiro, reviewed by Jeff Davis and Simon Riggs.
peculiar variant of UNION ALL, and so wouldn't likely get written directly
as-is, it's possible for it to arise as a result of simplification of
less-obviously-silly queries. In particular, now that we can do flattening
of subqueries that have constant outputs and are underneath an outer join,
it's possible for the case to result from simplification of queries of the
type exhibited in bug #5263. Back-patch to 8.4 to avoid a functionality
regression for this type of query.
This patch only supports seq_page_cost and random_page_cost as parameters,
but it provides the infrastructure to scalably support many more.
In particular, we may want to add support for effective_io_concurrency,
but I'm leaving that as future work for now.
Thanks to Tom Lane for design help and Alvaro Herrera for the review.
files when they haven't changed. This confuses make because the build fails
to update the file timestamps, and so it keeps on doing the action over again.
pg_attribute, by having genbki.pl derive the information from the various
catalog header files. This greatly simplifies modification of the
"bootstrapped" catalogs.
This patch finally kills genbki.sh and Gen_fmgrtab.sh; we now rely entirely on
Perl scripts for those build steps. To avoid creating a Perl build dependency
where there was not one before, the output files generated by these scripts
are now treated as distprep targets, ie, they will be built and shipped in
tarballs. But you will need a reasonably modern Perl (probably at least
5.6) if you want to build from a CVS pull.
The changes to the MSVC build process are untested, and may well break ---
we'll soon find out from the buildfarm.
John Naylor, based on ideas from Robert Haas and others
recovery instead of reading the backup history file. This is more robust,
as it stops you from prematurely starting up an inconsisten cluster if the
backup history file is lost for some reason, or if the base backup was
never finished with pg_stop_backup().
This also paves the way for a simpler streaming replication patch, which
doesn't need to care about backup history files anymore.
The backup history file is still created and archived as before, but it's
not used by the system anymore. It's just for informational purposes now.
Bump PG_CONTROL_VERSION as the location of the backup startpoint is now
written to a new field in pg_control, and catversion because initdb is
required
Original patch by Fujii Masao per Simon's idea, with further fixes by me.
"column < constant", and the comparison value is in the first or last
histogram bin or outside the histogram entirely, try to fetch the actual
column min or max value using an index scan (if there is an index on the
column). If successful, replace the lower or upper histogram bound with
that value before carrying on with the estimate. This limits the
estimation error caused by moving min/max values when the comparison
value is close to the min or max. Per a complaint from Josh Berkus.
It is tempting to consider using this mechanism for mergejoinscansel as well,
but that would inject index fetches into main-line join estimation not just
endpoint cases. I'm refraining from that until we can get a better handle
on the costs of doing this type of lookup.
indexscans would do the wrong thing if index_rescan() was called with a
NULL instead of a new set of scankeys and the index was DESC order,
because sk_strategy would not get flipped a second time. I think
that those provisions for a NULL argument are dead code now as far as the
core backend goes, but possibly somebody somewhere is still using it.
In any case, this refactoring seems clearer, and it's definitely shorter.
This is needed to avoid unwanted interference with SUBSTRING behavior,
as per bug #5257 from Roman Kononov. Also, add some basic intelligence
about character classes (bracket expressions) since we now have several
behaviors that aren't appropriate inside a character class.
As with the previous patch in this area, I'm reluctant to back-patch
since it might affect applications that are relying on the prior
behavior.
expressions: FormIndexDatum requires the estate's scantuple to already point
at the tuple the values are supposedly being extracted from. Adjust test
case so that this type of confusion will be exposed.
Per report from hubert depesz lubaczewski.
8.2beta but never carried out. This avoids repetitive tests of whether the
argument is of scalar or composite type. Also, be a bit more paranoid about
composite arguments in some places where we previously weren't checking.
to be just a minor extension of the previous patch that made "x IS NULL"
indexable, because we can treat the IS NOT NULL condition as if it were
"x < NULL" or "x > NULL" (depending on the index's NULLS FIRST/LAST option),
just like IS NULL is treated like "x = NULL". Aside from any possible
usefulness in its own right, this is an important improvement for
index-optimized MAX/MIN aggregates: it is now reliably possible to get
a column's min or max value cheaply, even when there are a lot of nulls
cluttering the interesting end of the index.
This is more in keeping with modern practice, and is a first step towards
porting to Win64 (which has sizeof(pointer) > sizeof(long)).
Tsutomu Yamada, Magnus Hagander, Tom Lane
decisions about when to auto-analyze.
The previous code depended on n_live_tuples + n_dead_tuples - last_anl_tuples,
where all three of these numbers could be bad estimates from ANALYZE itself.
Even worse, in the presence of a steady flow of HOT updates and matching
HOT-tuple reclamations, auto-analyze might never trigger at all, even if all
three numbers are exactly right, because n_dead_tuples could hold steady.
To fix, replace last_anl_tuples with an accurately tracked count of the total
number of committed tuple inserts + updates + deletes since the last ANALYZE
on the table. This can still be compared to the same threshold as before, but
it's much more trustworthy than the old computation. Tracking this requires
one more intra-transaction counter per modified table within backends, but no
additional memory space in the stats collector. There probably isn't any
measurable speed difference; if anything it might be a bit faster than before,
since I was able to eliminate some per-tuple arithmetic operations in favor of
adding sums once per (sub)transaction.
Also, simplify the logic around pgstat vacuum and analyze reporting messages
by not trying to fold VACUUM ANALYZE into a single pgstat message.
The original thought behind this patch was to allow scheduling of analyzes
on parent tables by artificially inflating their changes_since_analyze count.
I've left that for a separate patch since this change seems to stand on its
own merit.
at least in some Windows versions, these functions are capable of returning
a failure indication without setting errno. That puts us into an infinite
loop if the previous value happened to be EINTR. Per report from Brendan
Hill.
Back-patch to 8.2. We could take it further back, but since this is only
known to be an issue on Windows and we don't support Windows before 8.2,
it does not seem worth the trouble.
Since the int2vector type is intended only for internal use, this patch doesn't
worry about prettifying the error messages, which has the fringe benefit of
avoiding creating additional translatable strings. For a type intended to be
used by end-users, we would want to do better, but the approach taken here
seems like the correct trade-off for this case.
Caleb Welton
find_inheritance_children(). This is a complete no-op in databases without
any inheritance. In databases where there are just a few entries in
pg_inherits, it could conceivably be a small loss. However, in databases with
many inheritance parents, it can be a big win.
and teach ANALYZE to compute such stats for tables that have subclasses.
Per my proposal of yesterday.
autovacuum still needs to be taught about running ANALYZE on parent tables
when their subclasses change, but the feature is useful even without that.
PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.
Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.
Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.
The temporary hash tables made by pgstat_collect_oids should be allocated
in a short-term memory context, which is not the default behavior of
hash_create. Noted while looking through hash_create calls in connection
with Robert Haas' recent complaint.
This is a pre-existing bug, but it doesn't seem important enough to
back-patch. The hash table is not so large that it would matter unless this
happened many times within a session, which seems quite unlikely.
probably got there via blind copy-and-paste from one of the legitimate
callers, so rearrange and comment that code a bit to make it clearer that
this isn't a necessary prerequisite to hash_create. Per observation
from Robert Haas.
Modify pg_dump --binary-upgrade and add backend support routines to
support the preservation of pg_type oids when doing a binary upgrade.
This allows user-defined composite types and arrays to be binary
upgraded.
index page split. This would result in index corruption, or even more likely
an error during WAL replay, if we were unlucky enough to crash during
end-of-recovery cleanup after having completed an incomplete GIST insertion.
Yoichi Hirai
choose an index name the same as it would do for an unnamed index constraint.
(My recent changes to the index naming logic have helped to ensure that this
will be a reasonable choice.) Per a suggestion from Peter.
A necessary side-effect is to promote CONCURRENTLY to type_func_name_keyword
status, ie, it can't be a table/column/index name anymore unless quoted.
This is not all bad, since we have heard more than once of people typing
CREATE INDEX CONCURRENTLY ON foo (...) and getting a normal index build of
an index named "concurrently", which was not what they wanted. Now this
syntax will result in a concurrent build of an index with system-chosen
name; which they can rename afterwards if they want something else.
their underlying table columns. That code was not bright enough to cope with
collision situations (ie, new name conflicts with some other column of the
index). Since there is no functional reason to do this at all, trying to
upgrade the logic to be bulletproof doesn't seem worth the trouble.
This change means that both the index name and the column names of an index
are set when it's created, and won't be automatically changed when the
underlying table columns are renamed. Neatnik DBAs are still free to rename
them manually, of course.
CREATE FOREIGN DATA WRAPPER. Arguably it wasn't a bug because the
documentation said that it's passed the catalog ID or zero, but surely
we should provide it when it's known. And there isn't currently any
scenario where it's not known, and I can't imagine having one in the
future either, so better remove the "or zero" escape hatch and always
pass a valid catalog ID. Backpatch to 8.4.
Martin Pihlak
Index expression columns are now named after the FigureColname result for
their expressions, rather than always being "pg_expression_N". Digits are
appended to this name if needed to make the column name unique within the
index. (That happens for regular columns too, thus fixing the old problem
that CREATE INDEX fooi ON foo (f1, f1) fails. Before exclusion indexes
there was no real reason to do such a thing, but now maybe there is.)
Default names for indexes and associated constraints now include the column
names of all their columns, not only the first one as in previous practice.
(Of course, this will be truncated as needed to fit in NAMEDATALEN. Also,
pkey indexes retain the historical behavior of not naming specific columns
at all.)
An example of the results:
regression=# create table foo (f1 int, f2 text,
regression(# exclude (f1 with =, lower(f2) with =));
NOTICE: CREATE TABLE / EXCLUDE will create implicit index "foo_f1_lower_exclusion" for table "foo"
CREATE TABLE
regression=# \d foo_f1_lower_exclusion
Index "public.foo_f1_lower_exclusion"
Column | Type | Definition
--------+---------+------------
f1 | integer | f1
lower | text | lower(f2)
btree, for table "public.foo"
and composite types, which are the only relkinds for which pg_dump support
exists for dumping column comments. There is no obvious usefulness for
comments on columns of sequences or toast tables; and while comments on
index columns might have some value, it's not worth the risk of compatibility
problems due to possible changes in the algorithm for assigning names to
index columns. Per discussion.
In consequence, remove now-dead code for copying such comments in CREATE TABLE
LIKE.
Rewrite or adjust various comments for clarity. Remove one bogus comment that
doesn't reflect what the code actually does. Improve the description of the
lo_compat_privileges option.
have hard-wired knowledge of the rules for naming index columns. It can
just look at the actual names in the source index, instead. Do some minor
formatting cleanup too.
Magnus Hagander
Tom Lane
Simon Riggs
Itagaki Takahiro
Peter Eisentraut
Heikki Linnakangas
Robert Haas
Teodor Sigaev
Bruce Momjian
Andrew Dunstan