keeping private state in each backend that has inserted and deleted the same
tuple during its current top-level transaction. This is sufficient since
there is no need to be able to determine the cmin/cmax from any other
transaction. This gets us back down to 23-byte headers, removing a penalty
paid in 8.0 to support subtransactions. Patch by Heikki Linnakangas, with
minor revisions by moi, following a design hashed out awhile back on the
pghackers list.
already collected in the current transaction; this allows plpgsql functions to
watch for stats updates even though they are confined to a single transaction.
Use this instead of the previous kluge involving pg_stat_file() to wait for
the stats collector to update in the stats regression test. Internally,
decouple storage of stats snapshots from transaction boundaries; they'll
now stick around until someone calls pgstat_clear_snapshot --- which xact.c
still does at transaction end, to maintain the previous behavior. This makes
the logic a lot cleaner, at the price of a couple dozen cycles per transaction
exit.
observe the xmloption.
Reorganize the representation of the XML option in the parse tree and the
API to make it easier to manage and understand.
Add regression tests for parsing back XML expressions.
Standard English uses "may", "can", and "might" in different ways:
may - permission, "You may borrow my rake."
can - ability, "I can lift that log."
might - possibility, "It might rain today."
Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice. Similarly, "It may crash" is better stated, "It might crash".
nonportable "hh" sprintf(3) length modifier. Instead, do the parsing
and output by hand. The code to do this isn't ideal, but this is
an interim measure anyway: the uuid type should probably use the
in-memory struct layout specified by RFC 4122. For now, this patch
should hopefully rectify the buildfarm failures for the uuid test.
Along the way, re-add pg_cast entries for uuid <-> varchar, which
I mistakenly removed earlier, and bump the catversion.
In this case extractQuery should returns -1 as nentries. This changes
prototype of extractQuery method to use int32* instead of uint32* for
nentries argument.
Based on that gincostestimate may see two corner cases: nothing will be found
or seqscan should be used.
Per proposal at http://archives.postgresql.org/pgsql-hackers/2007-01/msg01581.php
PS tsearch_core patch should be sightly modified to support changes, but I'm
waiting a verdict about reviewing of tsearch_core patch.
Hashing for aggregation purposes still needs work, so it's not time to
mark any cross-type operators as hashable for general use, but these cases
work if the operators are so marked by hand in the system catalogs.
that defined in RFC 4122. This patch includes the basic implementation,
plus regression tests. Documentation and perhaps some additional
functionality will come later. Catversion bumped.
Patch from Gevik Babakhani; review from Peter, Tom, and myself.
versus varchar[]. This oversight probably explains Ryan Holmes' recent
complaint --- he was getting a generic selectivity estimate instead of
anything intelligent.
- Add new SQL command SET XML OPTION (also available via regular GUC) to
control the DOCUMENT vs. CONTENT option in implicit parsing and
serialization operations.
- Subtle corrections in the handling of the standalone property in
xmlroot().
- Allow xmlroot() to work on content fragments.
- Subtle corrections in the handling of the version property in
xmlconcat().
- Code refactoring for producing XML declarations.
page about the maximum UTF8 sequence length we support (4 bytes since 8.1,
3 before that). pg_utf2wchar_with_len never got updated to support 4-byte
characters at all, and in any case had a buffer-overrun risk in that it
could produce multiple pg_wchars from what mblen claims to be just one UTF8
character. The only reason we don't have a major security hole is that most
callers allocate worst-case output buffers; the sole exception in released
versions appears to be pre-8.2 iwchareq() (ie, ILIKE), which can be crashed
due to zeroing out its return address --- but AFAICS that can't be exploited
for anything more than a crash, due to inability to control what gets written
there. Per report from James Russell and Michael Fuhr.
Pre-8.1 the risk is much less, but I still think pg_utf2wchar_with_len's
behavior given an incomplete final character risks buffer overrun, so
back-patch that logic change anyway.
This patch also makes sure that UTF8 sequences exceeding the supported
length (whichever it is) are consistently treated as error cases, rather
than being treated like a valid shorter sequence in some places.
which I had removed in the first cut of the EquivalenceClass rewrite to
simplify that patch a little. But it's still important --- in a four-way
join problem mergejoinscansel() was eating about 40% of the planning time
according to gprof. Also, improve the EquivalenceClass code to re-use
join RestrictInfos rather than generating fresh ones for each join
considered. This saves some memory space but more importantly improves
the effectiveness of caching planning info in RestrictInfos.
columns procost and prorows, to allow simple user adjustment of the estimated
cost of a function call, as well as control of the estimated number of rows
returned by a set-returning function. We might eventually wish to extend this
to allow function-specific estimation routines, but there seems to be
consensus that we should try a simple constant estimate first. In particular
this provides a relatively simple way to control the order in which different
WHERE clauses are applied in a plan node, which is a Good Thing in view of the
fact that the recent EquivalenceClass planner rewrite made that much less
predictable than before.
provide just a boolean 'amcanorder', instead of fields that specify the
sort operator strategy numbers. We have decided to require ordering-capable
AMs to use btree-compatible strategy numbers, so the old fields are
overkill (and indeed misleading about what's allowed).
representation of equivalence classes of variables. This is an extensive
rewrite, but it brings a number of benefits:
* planner no longer fails in the presence of "incomplete" operator families
that don't offer operators for every possible combination of datatypes.
* avoid generating and then discarding redundant equality clauses.
* remove bogus assumption that derived equalities always use operators
named "=".
* mergejoins can work with a variety of sort orders (e.g., descending) now,
instead of tying each mergejoinable operator to exactly one sort order.
* better recognition of redundant sort columns.
* can make use of equalities appearing underneath an outer join.
The implementation is somewhat ugly logic-wise, but I don't see an
easy way to make it more concise.
When writing this, I noticed that my previous implementation of
width_bucket() doesn't handle NaN correctly:
postgres=# select width_bucket('NaN', 1, 5, 5);
width_bucket
--------------
6
(1 row)
AFAICS SQL:2003 does not define a NaN value, so it doesn't address how
width_bucket() should behave here. The patch changes width_bucket() so
that ereport(ERROR) is raised if NaN is specified for the operand or the
lower or upper bounds to width_bucket(). For float8, NaN is disallowed
for any of the floating-point inputs, and +/- infinity is disallowed
for the histogram bounds (but allowed for the operand).
Update docs and regression tests, bump the catversion.
standard convention the 21st century runs from 2001-2100, not 2000-2099,
so make it work like that. Per bug #2885 from Akio Iwaasa.
Backpatch to 8.2, but no further, since this is really a definitional
change; users of older branches are probably more interested in stability.
which comparison operators to use for plan nodes involving tuple comparison
(Agg, Group, Unique, SetOp). Formerly the executor looked up the default
equality operator for the datatype, which was really pretty shaky, since it's
possible that the data being fed to the node is sorted according to some
nondefault operator class that could have an incompatible idea of equality.
The planner knows what it has sorted by and therefore can provide the right
equality operator to use. Also, this change moves a couple of catalog lookups
out of the executor and into the planner, which should help startup time for
pre-planned queries by some small amount. Modify the planner to remove some
other cavalier assumptions about always being able to use the default
operators. Also add "nulls first/last" info to the Plan node for a mergejoin
--- neither the executor nor the planner can cope yet, but at least the API is
in place.
per-column options for btree indexes. The planner's support for this is still
pretty rudimentary; it does not yet know how to plan mergejoins with
nondefault ordering options. The documentation is pretty rudimentary, too.
I'll work on improving that stuff later.
Note incompatible change from prior behavior: ORDER BY ... USING will now be
rejected if the operator is not a less-than or greater-than member of some
btree opclass. This prevents less-than-sane behavior if an operator that
doesn't actually define a proper sort ordering is selected.
sets the items, and serializes the value back (rather than adding an
arbitrary number of XML preambles as before).
The libxml memory management via palloc had to be disabled because it
crashes when libxml tries to access memory that was helpfully freed
earlier by PostgreSQL. This needs further thought.
form '^(foo)$'. Before, these could never be optimized into indexscans.
The recent changes to make psql and pg_dump generate such patterns (for \d
commands and -t and related switches, respectively) therefore represented
a big performance hit for people with large pg_class catalogs, as seen in
recent gripe from Erik Jones. While at it, be more paranoid about
case-sensitivity checking in multibyte encodings, and fix some other
corner cases in which a regex might be interpreted too liberally.
The purpose is to allow autovacuum-esq conditional vacuuming and
clustering using SQL to discover the required stats.
No documentation updates required. Catalog version updated.
Glen Parker
valid result from a computation if one of the input values was infinity.
The previous code assumed an operation that returned infinity was an
overflow.
Handle underflow/overflow consistently, and add checks for aggregate
overflow.
Consistently prevent Inf/Nan from being cast to integer data types.
Fix INT_MIN % -1 to prevent overflow.
Update regression results for new error text.
Per report from Roman Kononov.
pg_opclass during LookupOpclassInfo(), I'd turned pg_opclass_oid_index
into a critical system index. However the problem could only manifest
during a backend's first attempt to load opclass data, and then only
if it had successfully loaded pg_internal.init and subsequently received
a relcache flush; which made it impossible to reproduce in sequential
tests and darn hard even in parallel tests. Memo to self: when
exercising cache flush scenarios, must disable LookupOpclassInfo's
internal cache too.
has a small maxBlockSize: the maximum request size that we will treat as a
"chunk" needs to be limited to fit in maxBlockSize. Otherwise we will round
up the request size to the next power of 2, wasting space, which is a bit
pointless if we aren't going to make the blocks big enough to fit additional
stuff in them. The example motivating this is local buffer management, which
makes repeated allocations of 8K (one BLCKSZ buffer) in TopMemoryContext,
which has maxBlockSize = 8K because for the most part allocations there are
small. This leads to each local buffer actually eating 16K of space, which
adds up when there are thousands of them. I intend to change localbuf.c to
aggregate its requests, which will prevent this particular misbehavior, but
it seems likely that similar scenarios could arise elsewhere, so fixing the
core problem seems wise as well.
Use a TRY block instead of (inadequate) ad-hoc coding to ensure that
libxml is cleaned up after a failure. Report the intended SQLCODE
instead of defaulting to XX000. Avoid risking use of a dangling
pointer by keeping the persistent error buffer in TopMemoryContext.
Be less trusting that error messages don't contain %.
This patch doesn't do anything about changing the way the messages
are put together --- this is just about mechanism.
bletcherous and unsafe manipulation of global encoding setting.
Clean up libxml reporting mechanism a bit (it still looks like a
dangling-pointer crash waiting to happen, though, not to mention
being far less than sane from a localization standpoint).
the XmlExpr code in various lists, use a representation that has some hope
of reverse-listing correctly (though it's still a de-escaping function
shy of correctness), generally try to make it look more like Postgres
coding conventions.
cases. Operator classes now exist within "operator families". While most
families are equivalent to a single class, related classes can be grouped
into one family to represent the fact that they are semantically compatible.
Cross-type operators are now naturally adjunct parts of a family, without
having to wedge them into a particular opclass as we had done originally.
This commit restructures the catalogs and cleans up enough of the fallout so
that everything still works at least as well as before, but most of the work
needed to actually improve the planner's behavior will come later. Also,
there are not yet CREATE/DROP/ALTER OPERATOR FAMILY commands; the only way
to create a new family right now is to allow CREATE OPERATOR CLASS to make
one by default. I owe some more documentation work, too. But that can all
be done in smaller pieces once this infrastructure is in place.
are all in new-in-8.2 logic associated with indexability of ScalarArrayOpExpr
(IN-clauses) or amortization of indexscan costs across repeated indexscans
on the inside of a nestloop. In particular:
Fix some logic errors in the estimation for multiple scans induced by a
ScalarArrayOpExpr indexqual.
Include a small cost component in bitmap index scans to reflect the costs of
manipulating the bitmap itself; this is mainly to prevent a bitmap scan from
appearing to have the same cost as a plain indexscan for fetching a single
tuple.
Also add a per-index-scan-startup CPU cost component; while prior releases
were clearly too pessimistic about the cost of repeated indexscans, the
original 8.2 coding allowed the cost of an indexscan to effectively go to zero
if repeated often enough, which is overly optimistic.
Pay some attention to index correlation when estimating costs for a nestloop
inner indexscan: this is significant when the plan fetches multiple heap
tuples per iteration, since high correlation means those tuples are probably
on the same or adjacent heap pages.
identify long-running transactions. Since we already need to record
the transaction-start time (e.g. for now()), we don't need any
additional system calls to report this information.
Catversion bumped, initdb required.
capitalize the strings like sentences. Remove unnecessarily
specific descriptions of the units used by GUC variables, since
we now allow any reasonable unit to be specified.
vacuum/analyze timestamp columns at the end, rather than at a random
spot in the middle as in the original patch. This was deemed more usable
as well as less likely to break existing application code. initdb forced
accordingly. In passing, remove former kluge for initializing
pg_stat_file()'s pg_proc entry --- bootstrap mode was fixed recently
so that this can be done without any hacks, but I overlooked this usage.
AbortTransaction, which would lead to recursion and eventual PANIC exit
as illustrated in recent report from Jeff Davis. First, in xact.c create
a special dedicated memory context for AbortTransaction to run in. This
solves the problem as long as AbortTransaction doesn't need more than 32K
(or whatever other size we create the context with). But in corner cases
it might. Second, in trigger.c arrange to keep pending after-trigger event
records in separate contexts that can be freed near the beginning of
AbortTransaction, rather than having them persist until CleanupTransaction
as before. Third, in portalmem.c arrange to free executor state data
earlier as well. These two changes should result in backing off the
out-of-memory condition before AbortTransaction needs any significant
amount of memory, at least in typical cases such as memory overrun due
to too many trigger events or too big an executor hash table. And all
the same for subtransaction abort too, of course.
because on that platform strftime produces localized zone names in varying
encodings. Even though it's only in a comment, this can cause encoding
errors when reloading the dump script. Per suggestion from Andreas
Seltenreich. Also, suppress %Z on Windows in the %s escape of
log_line_prefix ... not sure why this one is different from the other two,
but it shouldn't be.
Windows), arrange for each postmaster child process to be its own process
group leader, and deliver signals SIGINT, SIGTERM, SIGQUIT to the whole
process group not only the direct child process. This provides saner behavior
for archive and recovery scripts; in particular, it's possible to shut down a
warm-standby recovery server using "pg_ctl stop -m immediate", since delivery
of SIGQUIT to the startup subprocess will result in killing the waiting
recovery_command. Also, this makes Query Cancel and statement_timeout apply
to scripts being run from backends via system(). (There is no support in the
core backend for that, but it's widely done using untrusted PLs.) Per gripe
from Stephen Harris and subsequent discussion.
promoted to FATAL) end in exit(1) not exit(0). Then change the postmaster to
allow exit(1) without a system-wide panic, but not for the startup subprocess
or the bgwriter. There were a couple of places that were using exit(1) to
deliberately force a system-wide panic; adjust these to be exit(2) instead.
This fixes the problem noted back in July that if the startup process exits
with elog(ERROR), the postmaster would think everything is hunky-dory and
proceed to start up. Alternative solutions such as trying to run the entire
startup process as a critical section seem less clean, primarily because of
the fact that a fair amount of startup code is shared by all postmaster
children in the EXEC_BACKEND case. We'd need an ugly special case somewhere
near the head of main.c to make it work if it's the child process's
responsibility to determine what happens; and what's the point when the
postmaster already treats different children differently?
cases where we already hold the desired lock "indirectly", either via
membership in a MultiXact or because the lock was originally taken by a
different subtransaction of the current transaction. These cases must be
accounted for to avoid needless deadlocks and/or inappropriate replacement of
an exclusive lock with a shared lock. Per report from Clarence Gardner and
subsequent investigation.
of an index on a serial column, rather than the name of the associated
sequence. Fallout from recent changes in dependency setup for serials.
Per bug #2732 from Basil Evseenko.
The former coding relied on the actual allocated size of the last block,
which made it behave strangely if the first allocation in a context was
larger than ALLOC_CHUNK_LIMIT: subsequent allocations would be referenced
to that and not to the intended series of block sizes. Noted while
studying a memory wastage gripe from Tatsuo.
more space is needed, instead of incrementing by a fixed amount; the old
method wastes lots of space and time when the ultimate size is large.
Per gripe from Tatsuo.
text_to_array(): they all had O(N^2) behavior on long input strings in
multibyte encodings, because of repeated rescanning of the input text to
identify substrings whose positions/lengths were computed in characters
instead of bytes. Fix by tracking the current source position as a char
pointer as well as a character-count. Also avoid some unnecessary palloc
operations. text_to_array() also leaked memory intracall due to failure
to pfree temporary strings. Per gripe from Tatsuo Ishii.
stale relcache init files (pg_internal.init), and there is no mechanism for
updating them during WAL replay. Easiest solution is just to delete the init
files at conclusion of startup, and let the first backend started in each
database take care of rebuilding the init file. Simon Riggs and Tom Lane.
Back-patched to 8.1. Arguably this should be fixed in 8.0 too, but it would
require significantly more code since 8.0 has no handy startup-time scan of
pg_database to piggyback on. Manual solution of the problem is possible
in 8.0 (just delete the pg_internal.init files before starting WAL replay),
so that may be a sufficient answer.
in PITR scenarios. We now WAL-log the replacement of old XIDs with
FrozenTransactionId, so that such replacement is guaranteed to propagate to
PITR slave databases. Also, rather than relying on hint-bit updates to be
preserved, pg_clog is not truncated until all instances of an XID are known to
have been replaced by FrozenTransactionId. Add new GUC variables and
pg_autovacuum columns to allow management of the freezing policy, so that
users can trade off the size of pg_clog against the amount of freezing work
done. Revise the already-existing code that forces autovacuum of tables
approaching the wraparound point to make it more bulletproof; also, revise the
autovacuum logic so that anti-wraparound vacuuming is done per-table rather
than per-database. initdb forced because of changes in pg_class, pg_database,
and pg_autovacuum catalogs. Heikki Linnakangas, Simon Riggs, and Tom Lane.
timezone actually has a daylight-savings rule. This avoids breaking
cases that used to work because they went through the DecodePosixTimezone
code path. Per contrib regression failures (mea culpa for not running
those yesterday...). Also document the already-applied change to allow
GMT offsets up to 14 hours.
input routines. Remove the former "DecodePosixTimezone" function in favor of
letting the zic code handle POSIX-style zone specs (see tzparse()). In
particular this means that "PST+3" now means the same as "-03", whereas it
used to mean "-11" --- the zone abbreviation is effectively just a noise word
in this syntax. Make sure that all named and POSIX-style zone names will be
parsed as a single token. Fix long-standing bogosities in printing and input
of fractional-hour timezone offsets (since the tzparse() code will accept
these, we'd better make 'em work). Also correct an error in the original
coding of the zic-zone-name patch: in "timestamp without time zone" input,
zone names are supposed to be allowed but ignored, but the coding was such
that the zone changed the interpretation anyway.
max_stack_depth is not set to an unsafe value.
This commit also provides configure-time checking for <sys/resource.h>,
and cleans up some perhaps-unportable code associated with use of that
include file and getrlimit().
overlapping possible matches for the separator string, such as
string_to_array('123xx456xxx789', 'xx').
Also, revise the logic of replace(), split_part(), and string_to_array()
to avoid O(N^2) work from redundant searches and conversions to pg_wchar
format when there are N matches to the separator string.
Backpatched the full patch as far as 8.0. 7.4 also has the bug, but the
code has diverged a lot, so I just went for a quick-and-dirty fix of the
bug itself in that branch.
been initialized yet. This can happen because there are code paths that call
SysCacheGetAttr() on a tuple originally fetched from a different syscache
(hopefully on the same catalog) than the one specified in the call. It
doesn't seem useful or robust to try to prevent that from happening, so just
improve the function to cope instead. Per bug#2678 from Jeff Trout. The
specific example shown by Jeff is new in 8.1, but to be on the safe side
I'm backpatching 8.0 as well. We could patch 7.x similarly but I think
that's probably overkill, given the lack of evidence of old bugs of this ilk.
remaining functions, simplify pglz_compress's API to not require a useless
data copy when compression fails. Also add a check in pglz_decompress that
the expected amount of data was decompressed.
repeatedly. Now that we don't have to worry about memory leaks from
glibc's qsort, we can safely put CHECK_FOR_INTERRUPTS into the tuplesort
comparators, as was requested a couple months ago. Also, get rid of
non-reentrancy and an extra level of function call in tuplesort.c by
providing a variant qsort_arg() API that passes an extra void * argument
through to the comparison routine. (We might want to use that in other
places too, I didn't look yet.)
postgresql.conf.
- shared_buffers = 32000kB => 32MB
- temp_buffers = 8000kB => 8MB
- wal_buffers = 8 => 64kB
The code of initdb was a bit modified to write MB-unit values.
Values greater than 8000kB are rounded out to MB.
GUC_UNIT_XBLOCKS is added for wal_buffers. It is like GUC_UNIT_BLOCKS,
but uses XLOG_BLCKSZ instead of BLCKSZ.
Also, I cleaned up the test of GUC_UNIT_* flags in preparation to
add more unit flags in less bits.
ITAGAKI Takahiro
severity. This is to ensure the user can cancel a query that's spitting
out lots of notice/warning messages, even if they're coming from a loop
that doesn't otherwise contain a CHECK_FOR_INTERRUPTS. Per gripe from
Stephen Frost.
present; intervening positions are filled with nulls. This behavior
is required by SQL99 but was not implementable before 8.2 due to lack
of support for nulls in arrays. I have only made it work for the
one-dimensional case, which is all that SQL99 requires. It seems quite
complex to get it right in higher dimensions, and since we never allowed
extension at all in higher dimensions, I think that must count as a
future feature addition not a bug fix.
the SQL spec, viz IS NULL is true if all the row's fields are null, IS NOT
NULL is true if all the row's fields are not null. The former coding got
this right for a limited number of cases with IS NULL (ie, those where it
could disassemble a ROW constructor at parse time), but was entirely wrong
for IS NOT NULL. Per report from Teodor.
I desisted from changing the behavior for arrays, since on closer inspection
it's not clear that there's any support for that in the SQL spec. This
probably needs more consideration.
to performance. (A wholesale effort to get rid of strncpy should be
undertaken sometime, but not during beta.) This commit also fixes dynahash.c
to correctly truncate overlength string keys for hashtables, so that its
callers don't have to anymore.
return true for exactly the characters treated as whitespace by their flex
scanners. Per report from Victor Snezhko and subsequent investigation.
Also fix a passel of unsafe usages of <ctype.h> functions, that is, ye olde
char-vs-unsigned-char issue. I won't miss <ctype.h> when we are finally
able to stop using it.
is a large enough histogram, it will use the number of matches in the
histogram to derive a selectivity estimate, rather than the admittedly
pretty bogus heuristics involving examining the pattern contents. I set
'large enough' at 100, but perhaps we should change that later. Also
apply the same technique in contrib/ltree's <@ and @> estimator. Per
discussion with Stefan Kaltenbrunner and Matteo Beccati.
tables in the query compete for cache space, not just the one we are
currently costing an indexscan for. This seems more realistic, and it
definitely will help in examples recently exhibited by Stefan
Kaltenbrunner. To get the total size of all the tables involved, we must
tweak the handling of 'append relations' a bit --- formerly we looked up
information about the child tables on-the-fly during set_append_rel_pathlist,
but it needs to be done before we start doing any cost estimation, so
push it into the add_base_rels_to_query scan.
contrib functionality. Along the way, remove the USER_LOCKS configuration
symbol, since it no longer makes any sense to try to compile that out.
No user documentation yet ... mmoncure has promised to write some.
Thanks to Abhijit Menon-Sen for creating a first draft to work from.
and create a new view pg_timezone_names that provides information about
the zones known in the 'zic' database. Magnus Hagander, with some
additional work by Tom Lane.
Peter Eisentraut
Bruce Momjian
Tom Lane
Neil Conway
Teodor Sigaev
Alvaro Herrera
D'Arcy J.M. Cain