no need for serialization against snapshot-taking because the xact doesn't
affect anyone else's snapshot anyway. Per discussion. Also, move various
info about the interlocking of transactions and snapshots out of code comments
and into a hopefully-more-cohesive discussion in access/transam/README.
Also, remove a couple of now-obsolete comments about having to force some WAL
to be written to persuade RecordTransactionCommit to do its thing.
big misalignement, then it tries to split page basing on distribution
of boxe's centers.
Per report from Dolafi, Tom <dolafit@janelia.hhmi.org>
Backpatch is needed, change doesn't affect on-disk storage.
- change the alignment requirement of lexemes in TSVector slightly.
Lexeme strings were always padded to 2-byte aligned length to make sure
that if there's position array (uint16[]) it has the right alignment.
The patch changes that so that the padding is not done when there's no
positions. That makes the storage of tsvectors without positions
slightly more compact.
- added some #include "miscadmin.h" lines I missed in the earlier when I
added calls to check_stack_depth().
- Reimplement the send/recv functions, and added a comment
above them describing the on-wire format. The CRC is now recalculated in
tsquery as well per previous discussion.
- add code to check that the query tree is well-formed. It was indeed
possible to send malformed queries in binary mode, which produced all
kinds of strange results.
- make the left-field a uint32. There's no reason to
arbitrarily limit it to 16-bits, and it won't increase the disk/memory
footprint either now that QueryOperator and QueryOperand are separate
structs.
- add check_stack_depth() call to all recursive functions I found.
Some of them might have a natural limit so that you can't force
arbitrarily deep recursions, but check_stack_depth() is cheap enough
that seems best to just stick it into anything that might be a problem.
small editorization by me
- Brake the QueryItem struct into QueryOperator and QueryOperand.
Type was really the only common field between them. QueryItem still
exists, and is used in the TSQuery struct as before, but it's now a
union of the two. Many other changes fell from that, like separation
of pushval_asis function into pushValue, pushOperator and pushStop.
- Moved some structs that were for internal use only from header files
to the right .c-files.
- Moved tsvector parser to a new tsvector_parser.c file. Parser code was
about half of the size of tsvector.c, it's also used from tsquery.c, and
it has some data structures of its own, so it seems better to separate
it. Cleaned up the API so that TSVectorParserState is not accessed from
outside tsvector_parser.c.
- Separated enumerations (#defines, really) used for QueryItem.type
field and as return codes from gettoken_query. It was just accidental
code sharing.
- Removed ParseQueryNode struct used internally by makepol and friends.
push*-functions now construct QueryItems directly.
- Changed int4 variables to just ints for variables like "i" or "array
size", where the storage-size was not significant.
null::char(3) to a simple Const node. (It already worked for non-null values,
but not when we skipped evaluation of a strict coercion function.) This
prevents loss of typmod knowledge in situations such as exhibited in bug
#3598. Unfortunately there seems no good way to fix that bug in 8.1 and 8.2,
because they simply don't carry a typmod for a plain Const node.
In passing I made all the other callers of makeNullConst supply "real" typmod
values too, though I think it probably doesn't matter anywhere else.
that examine fields that could change under them. This is just to make
really sure that when we are fetching a value 'only once', that's what
actually happens. Possibly this is a bug that should be back-patched,
but in the absence of solid evidence that it's needed, I won't bother.
rows will normally never obtain an XID at all. We already did things this way
for subtransactions, but this patch extends the concept to top-level
transactions. In applications where there are lots of short read-only
transactions, this should improve performance noticeably; not so much from
removal of the actual XID-assignments, as from reduction of overhead that's
driven by the rate of XID consumption. We add a concept of a "virtual
transaction ID" so that active transactions can be uniquely identified even
if they don't have a regular XID. This is a much lighter-weight concept:
uniqueness of VXIDs is only guaranteed over the short term, and no on-disk
record is made about them.
Florian Pflug, with some editorialization by Tom.
(Actually, it works as a plain statement too, but I didn't document that
because it seems a bit useless.) Unify VariableResetStmt with
VariableSetStmt, and clean up some ancient cruft in the representation of
same.
initcap style --- the vast majority of the existing descriptions do not use
an initial cap. I didn't change places where the first word was all-cap.
initdb not forced because this doesn't change any regression test results.
There are still some loose ends: I didn't do anything about the SET FROM
CURRENT idea yet, and it's not real clear whether we are happy with the
interaction of SET LOCAL with function-local settings. The documentation
is a bit spartan, too.
regardless of the number of tuples involved, it's incorrect to skip it
when memtupcount = 1; the number of cycles saved is minuscule anyway.
An alternative solution would be to pull the state changes out to the
call site in tuplesort_performsort, but keeping them near the corresponding
changes in make_bounded_heap seems marginally cleaner. Noticed by
Greg Stark.
the number of rows likely to be produced by a query such as
SELECT * FROM t1 LEFT JOIN t2 USING (key) WHERE t2.key IS NULL;
What this is doing is selecting for t1 rows with no match in t2, and thus
it may produce a significant number of rows even if the t2.key table column
contains no nulls at all. 8.2 thinks the table column's null fraction is
relevant and thus may estimate no rows out, which results in terrible plans
if there are more joins above this one. A proper fix for this will involve
passing much more information about the context of a clause to the selectivity
estimator functions than we ever have. There's no time left to write such a
patch for 8.3, and it wouldn't be back-patchable into 8.2 anyway. Instead,
put in an ad-hoc test to defeat the normal table-stats-based estimation when
an IS NULL test is evaluated at an outer join, and just use a constant
estimate instead --- I went with 0.5 for lack of a better idea. This won't
catch every case but it will catch the typical ways of writing such queries,
and it seems unlikely to make things worse for other queries.
generating the tuples has resjunk output columns. This is not possible for
simple table scans but can happen when evaluating a whole-row Var for a view.
Per example from Patryk Kordylewski. The problem exists back to 8.0 but
I'm not going to risk back-patching further than 8.2 because of the many
changes in this area.
sets for outer joins, in the light of bug #3588 and additional thought and
experimentation. The original methodology was fatally flawed for nests of
more than two outer joins: it got the relationships between adjacent joins
right, but didn't always come to the right conclusions about whether a join
could be interchanged with one two or more levels below it. This was largely
caused by a mistaken idea that we should use the min_lefthand + min_righthand
sets of a sub-join as the minimum left or right input set of an upper join
when we conclude that the sub-join can't commute with the upper one. If
there's a still-lower join that the sub-join *can* commute with, this method
led us to think that that one could commute with the topmost join; which it
can't. Another problem (not directly connected to bug #3588) was that
make_outerjoininfo's processing-order-dependent method for enforcing outer
join identity #3 didn't work right: if we decided that join A could safely
commute with lower join B, we dropped all information about sub-joins under B
that join A could perhaps not safely commute with, because we removed B's
entire min_righthand from A's.
To fix, make an explicit computation of all inner join combinations that occur
below an outer join, and add to that the full syntactic relsets of any lower
outer joins that we determine it can't commute with. This method gives much
more direct enforcement of the outer join rearrangement identities, and it
turns out not to cost a lot of additional bookkeeping.
Thanks to Richard Harris for the bug report and test case.
checks for individual-table-size functions, since anyone in the database could
get approximate values from pg_class.relpages anyway. Allow database-size to
users with CONNECT privilege for the target database (note that this is
granted by default). Allow tablespace-size if the user has CREATE privilege
on the tablespace (which is *not* granted by default), or if the tablespace is
the default tablespace for the current database (since we treat that as
implicitly allowing use of the tablespace).
even if the "deadlock detected" ERROR message is suppressed by an exception
catcher. Be clearer about the event sequence when a soft deadlock is fixed:
the fixing process might or might not still have to wait, so log that
separately. Fix race condition when someone releases us from the lock partway
through printing all this junk --- we'd not get confused about our state, but
the log message sequence could have been misleading, ie, a "still waiting"
message with no subsequent "acquired" message. Greg Stark and Tom Lane.
namespace isn't necessarily first in the search path (there could be implicit
schemas ahead of it). Examples are
test=# set search_path TO s1;
test=# create view pg_timezone_names as select * from pg_timezone_names();
ERROR: "pg_timezone_names" is already a view
test=# create table pg_class (f1 int primary key);
ERROR: permission denied: "pg_class" is a system catalog
You'd expect these commands to create the requested objects in s1, since
names beginning with pg_ aren't supposed to be reserved anymore. What is
happening is that we create the requested base table and then execute
additional commands (here, CREATE RULE or CREATE INDEX), and that code is
passed the same RangeVar that was in the original command. Since that
RangeVar has schemaname = NULL, the secondary commands think they should do a
path search, and that means they find system catalogs that are implicitly in
front of s1 in the search path.
This is perilously close to being a security hole: if the secondary command
failed to apply a permission check then it'd be possible for unprivileged
users to make schema modifications to system catalogs. But as far as I can
find, there is no code path in which a check doesn't occur. Which makes it
just a weird corner-case bug for people who are silly enough to want to
name their tables the same as a system catalog.
The relevant code has changed quite a bit since 8.2, which means this patch
wouldn't work as-is in the back branches. Since it's a corner case no one
has reported from the field, I'm not going to bother trying to back-patch.
days that was obsolete the moment we had IN (SELECT ...) capability.
It's arguably a security hole since it applied no permissions check to
the table it searched, and since it was never documented anywhere,
removing it seems more appropriate than fixing it.
and pg_tablespace_size to superusers. Perhaps we could weaken the first
case to just require SELECT privilege, but that doesn't work for the
other cases, so use ownership as the common concept.
While it's not clear that TID linkage info is of any great use to a
nefarious user, it's certainly unexpected that these functions wouldn't
insist on read privileges.
relcache entry after having heap_close'd it. This could lead to misbehavior
if a relcache flush wiped out the cache entry meanwhile. In 8.2 there is a
very real risk of CREATE INDEX CONCURRENTLY using the wrong relid for locking
and waiting purposes. I think the bug is only cosmetic in 8.0 and 8.1,
because their transgression is limited to using RelationGetRelationName(rel)
in an ereport message immediately after heap_close, and there's no way (except
with special debugging options) for a cache flush to occur in that interval.
Not quite sure that it's cosmetic in 7.4, but seems best to patch anyway.
Found by trying to run the regression tests with CLOBBER_CACHE_ALWAYS enabled.
Maybe we should try to do that on a regular basis --- it's awfully slow,
but perhaps some fast buildfarm machine could do it once in awhile.
- ispell initialization crashed on empty dictionary file
- ispell initialization crashed on affix file with prefixes but no suffixes
- stop words file was run through pg_verify_mbstr, with database
encoding, but it's supposed to be UTF-8; similar bug for synonym files
- bunch of comments added, typos fixed, and other cleanup
Introduced consistent encoding checking/conversion of data read from tsearch
configuration files, by doing this in a single t_readline() subroutine
(replacing direct usages of fgets). Cleaned up API for readstopwords too.
Heikki Linnakangas
This prevents needing to do complex and poorly-defined updates of the
mapping table if the new parser has different token types than the old.
Per discussion.
init options of the template as top-level options in the syntax. This also
makes ALTER a bit easier to use, since options can be replaced individually.
I also made these statements verify that the tmplinit method will accept
the new settings before they get stored; in the original coding you didn't
find out about mistakes until the dictionary got invoked.
Under the hood, init methods now get options as a List of DefElem instead
of a raw text string --- that lets tsearch use existing options-pushing code
instead of duplicating functionality.
'with map' parameter; as things now stand there's really not much point
in specifying a config-to-copy if you don't copy its map. Also, use
COPY instead of TEMPLATE as the key word for a config-to-copy, so as
to avoid confusion with text search templates. Per discussion; the
just-committed reference page for the command already describes it
this way.
byte after the last full byte of the bit array, regardless of whether that
byte was part of the valid data or not. Found by buildfarm testing.
Thanks to Stefan Kaltenbrunner for nailing down the cause.
Tom Lane
Teodor Sigaev
Andrew Dunstan
Magnus Hagander