This was accidentally broken in commits cfa1b4a711/5e8e794e3b.
It saves a line or so to call ftello unconditionally in _CloseArchive,
but we have to expect that it might fail if we're not in hasSeek mode.
Per report from Bernd Helmle.
In passing, improve _getFilePos to print an appropriate message if
ftello fails unexpectedly, rather than just a vague complaint about
"ftell mismatch".
Rather than reset errno (or just hope that its cleared already),
check just the result of the ftello for < 0 to determine if there
was an issue.
Oversight by me, pointed out by Tom.
Improve pg_dump by checking results on various fgetc() calls which
previously were unchecked, ditto for ftello. Also clean up a couple
of very minor memory leaks by waiting to allocate structures until
after the initial check(s).
Issues spotted by Coverity.
Move functions used only by pg_dump and pg_restore from dumputils.c to a new
file, pg_backup_utils.c. dumputils.c is linked into psql and some programs
in bin/scripts, so it seems good to keep it slim. The parallel functionality
is moved to parallel.c, as is exit_horribly, because the interesting code in
exit_horribly is parallel-related.
This refactoring gets rid of the on_exit_msg_func function pointer. It was
problematic, because a modern gcc version with -Wmissing-format-attribute
complained if it wasn't marked with PF_PRINTF_ATTRIBUTE, but the ancient gcc
version that Tom Lane's old HP-UX box has didn't accept that attribute on a
function pointer, and gave an error. We still use a similar function pointer
trick for getLocalPQBuffer() function, to use a thread-local version of that
in parallel mode on Windows, but that dodges the problem because it doesn't
take printf-like arguments.
New infrastructure is added which creates a set number of workers
(threads on Windows, forked processes on Unix). Jobs are then
handed out to these workers by the master process as needed.
pg_restore is adjusted to use this new infrastructure in place of the
old setup which created a new worker for each step on the fly. Parallel
dumps acquire a snapshot clone in order to stay consistent, if
available.
The parallel option is selected by the -j / --jobs command line
parameter of pg_dump.
Joachim Wieland, lightly editorialized by Andrew Dunstan.
libpgcommon is a new static library to allow sharing code among the
various frontend programs and backend; this lets us eliminate duplicate
implementations of common routines. We avoid libpgport, because that's
intended as a place for porting issues; per discussion, it seems better
to keep them separate.
The first use case, and the only implemented by this patch, is pg_malloc
and friends, which many frontend programs were already using.
At the same time, we can use this to provide palloc emulation functions
for the frontend; this way, some palloc-using files in the backend can
also be used by the frontend cleanly. To do this, we change palloc() in
the backend to be a function instead of a macro on top of
MemoryContextAlloc(). This was previously believed to cause loss of
performance, but this implementation has been tweaked by Tom and Andres
so that on modern compilers it provides a slight improvement over the
previous one.
This lets us clean up some places that were already with
localized hacks.
Most of the pg_malloc/palloc changes in this patch were authored by
Andres Freund. Zoltán Böszörményi also independently provided a form of
that. libpgcommon infrastructure was authored by Álvaro.
We had a number of variants on the theme of "malloc or die", with the
majority named like "pg_malloc", but by no means all. Standardize on the
names pg_malloc, pg_malloc0, pg_realloc, pg_strdup. Get rid of pg_calloc
entirely in favor of using pg_malloc0.
This is an essentially cosmetic change, so no back-patch. (I did find
a couple of places where psql and pg_dump were using plain malloc or
strdup instead of the pg_ versions, but they don't look significant
enough to bother back-patching.)
The old code was using exit_horribly or die_horribly other depending on
whether it had an ArchiveHandle on which to close the connection or not;
but there were places that were passing a NULL ArchiveHandle to
die_horribly, and other places that used exit_horribly while having an
AH available. So there wasn't all that much consistency.
Improve the situation by keeping only one of the routines, and instead
of having to pass the AH down from the caller, arrange for it to be
present for an on_exit_nicely callback to operate on.
Author: Joachim Wieland
Some tweaks by me
Per a suggestion from Robert Haas, in the ongoing "parallel pg_dump"
saga.
If we are unable to do a parallel restore because the input file is stdin
or is otherwise unseekable, we should complain and fail immediately, not
after having done some of the restore. Complaining once per thread isn't
so cool either, and the messages should be worded to make it clear this is
an unsupported case not some weird race-condition bug. Per complaint from
Lonni Friedman.
Back-patch to 8.4, where parallel restore was introduced.
This warning is new in gcc 4.6 and part of -Wall. This patch cleans
up most of the noise, but there are some still warnings that are
trickier to remove.
to make it easier to reuse that code. There is no user-visible changes.
This is in preparation for the patch to add a new archive format, a directory,
to perform a custom-like dump but with each table being dumped to a separate
file (that in turn is a prerequisite for parallel pg_dump). This also makes it
easier to add new compression methods in the future, and makes the
pg_backup_custom.c code easier to read, when the compression-related code is
factored out.
Joachim Wieland, with heavy editorialization by me.
as well as fseeko, and to not assume that fseeko(fp, 0, SEEK_CUR) proves
anything. Also improve some related comments. Per my observation that
the SEEK_CUR test didn't actually work on some platforms, and subsequent
discussion with Robert Haas.
Back-patch to 8.4. In earlier releases it's not that important whether
we get the hasSeek test right, but with parallel restore it matters.
contain data offsets (which it won't, if pg_dump thought its output wasn't
seekable). To do that, remove an unnecessarily aggressive error check, and
instead fail if we get to the end of the archive without finding the desired
data item. Also improve the error message to be more specific about the
cause of the problem. Per discussion of recent report from Igor Neyman.
Back-patch to 8.4 where parallel restore was introduced.
post-data step is run in a separate worker child (a thread on Windows, a child
process elsewhere) up to the concurrent number specified by the new pg_restore
command-line --multi-thread | -m switch.
Andrew Dunstan, with some editing by Tom Lane.
using the recently added lo_create() function. The restore logic in
pg_restore is greatly simplified as well, since there's no need anymore
to try to adjust database references to match a new set of blob OIDs.
object types, rather than by OID. This should help ensure consistent
dump output from databases that are logically the same but have different
histories, per recent discussion about 'diffing' databases. The patch
is bulky because of renaming of fields, but not very complicated.
Also, do some tweaking to cause BLOB restoration to be done in a better
order, and clean up pg_restore's textual output to exactly match pg_dump.
pg_depend to determine a safe dump order. Defaults and check constraints
can be emitted either as part of a table or domain definition, or
separately if that's needed to break a dependency loop. Lots of old
half-baked code for controlling dump order removed.
