Commit Graph

27 Commits

Author SHA1 Message Date
Heikki Linnakangas
5028f22f6e Switch to CRC-32C in WAL and other places.
The old algorithm was found to not be the usual CRC-32 algorithm, used by
Ethernet et al. We were using a non-reflected lookup table with code meant
for a reflected lookup table. That's a strange combination that AFAICS does
not correspond to any bit-wise CRC calculation, which makes it difficult to
reason about its properties. Although it has worked well in practice, seems
safer to use a well-known algorithm.

Since we're changing the algorithm anyway, we might as well choose a
different polynomial. The Castagnoli polynomial has better error-correcting
properties than the traditional CRC-32 polynomial, even if we had
implemented it correctly. Another reason for picking that is that some new
CPUs have hardware support for calculating CRC-32C, but not CRC-32, let
alone our strange variant of it. This patch doesn't add any support for such
hardware, but a future patch could now do that.

The old algorithm is kept around for tsquery and pg_trgm, which use the
values in indexes that need to remain compatible so that pg_upgrade works.
While we're at it, share the old lookup table for CRC-32 calculation
between hstore, ltree and core. They all use the same table, so might as
well.
2014-11-04 11:39:48 +02:00
Bruce Momjian
6a605cd6bd Adjust blank lines around PG_MODULE_MAGIC defines, for consistency
Report by Robert Haas
2014-07-10 14:02:08 -04:00
Peter Eisentraut
e7128e8dbb Create function prototype as part of PG_FUNCTION_INFO_V1 macro
Because of gcc -Wmissing-prototypes, all functions in dynamically
loadable modules must have a separate prototype declaration.  This is
meant to detect global functions that are not declared in header files,
but in cases where the function is called via dfmgr, this is redundant.
Besides filling up space with boilerplate, this is a frequent source of
compiler warnings in extension modules.

We can fix that by creating the function prototype as part of the
PG_FUNCTION_INFO_V1 macro, which such modules have to use anyway.  That
makes the code of modules cleaner, because there is one less place where
the entry points have to be listed, and creates an additional check that
functions have the right prototype.

Remove now redundant prototypes from contrib and other modules.
2014-04-18 00:03:19 -04:00
Tom Lane
c3ccc9ee58 Fix possible buffer overrun in contrib/pg_trgm.
Allow for the possibility that folding a string to lower case makes it
longer (due to replacing a character with a longer multibyte character).
This doesn't change the number of trigrams that will be extracted, but
it does affect the required size of an intermediate buffer in
generate_trgm().  Per bug #8821 from Ufuk Kayserilioglu.

Also install some checks that the input string length is not so large
as to cause overflow in the calculations of palloc request sizes.

Back-patch to all supported versions.
2014-01-13 13:07:10 -05:00
Bruce Momjian
9af4159fce pgindent run for release 9.3
This is the first run of the Perl-based pgindent script.  Also update
pgindent instructions.
2013-05-29 16:58:43 -04:00
Tom Lane
6f5b8beb64 Make contrib/pg_trgm also support regex searches with GiST indexes.
This wasn't addressed in the original patch, but it doesn't take very
much additional code to cover the case, so let's get it done.

Since pg_trgm 1.1 hasn't been released yet, I just changed the definition
of what's in it, rather than inventing a 1.2.
2013-04-10 13:31:02 -04:00
Tom Lane
3ccae48f44 Support indexing of regular-expression searches in contrib/pg_trgm.
This works by extracting trigrams from the given regular expression,
in generally the same spirit as the previously-existing support for
LIKE searches, though of course the details are far more complicated.

Currently, only GIN indexes are supported.  We might be able to make
it work with GiST indexes later.

The implementation includes adding API functions to backend/regex/
to provide a view of the search NFA created from a regular expression.
These functions are meant to be generic enough to be supportable in
a standalone version of the regex library, should that ever happen.

Alexander Korotkov, reviewed by Heikki Linnakangas and Tom Lane
2013-04-09 01:06:54 -04:00
Tom Lane
7844608e54 Get rid of USE_WIDE_UPPER_LOWER dependency in trigram construction.
contrib/pg_trgm's make_trigrams() was coded to ignore multibyte character
boundaries and just make trigrams from bytes if USE_WIDE_UPPER_LOWER wasn't
defined.  This is a bit odd, since there's no obvious reason why trigram
compaction rules should depend on the presence of towlower() and friends.
What's more, there was an Assert() that would fail if that code path was
fed any multibyte characters.

We need to do something about this since the pending regex-indexing patch
has an assumption that you get just one "trgm" from any three characters.
The best solution seems to be to remove the USE_WIDE_UPPER_LOWER
dependency, which shouldn't really have been there in the first place.
The second loop in make_trigrams() is now just a fast path and not a
potentially incompatible algorithm.

If there is anybody still using Postgres on machines without wcstombs() or
towlower(), and they have non-ASCII data indexed by pg_trgm, they'll need
to REINDEX those indexes after pg_upgrade to 9.3, else searches may fail
incorrectly. It seems likely that there are no such installations, though.

In passing, rename cnt_trigram to compact_trigram, which seems to better
describe its functionality, and improve make_trigrams' test for whether it
has to use the slow path or not (per a suggestion from Alexander Korotkov).
2013-04-07 14:46:17 -04:00
Tom Lane
9728eda792 Fix contrib/pg_trgm's similarity() function for trigram-free strings.
Cases such as similarity('', '') produced a NaN result due to computing
0/0.  Per discussion, make it return zero instead.

This appears to be the basic cause of bug #7867 from Michele Baravalle,
although it remains unclear why her installation doesn't think Cyrillic
letters are letters.

Back-patch to all active branches.
2013-02-13 14:07:06 -05:00
Tom Lane
b2a01b9ad1 Fix bugs in contrib/pg_trgm's LIKE pattern analysis code.
Extraction of trigrams did not process LIKE escape sequences properly,
leading to possible misidentification of trigrams near escapes, resulting
in incorrect index search results.

Fujii Masao
2012-08-20 13:25:42 -04:00
Bruce Momjian
6416a82a62 Remove unnecessary #include references, per pgrminclude script. 2011-09-01 10:04:27 -04:00
Bruce Momjian
bf50caf105 pgindent run before PG 9.1 beta 1. 2011-04-10 11:42:00 -04:00
Tom Lane
6e2f3ae884 Support LIKE and ILIKE index searches via contrib/pg_trgm indexes.
Unlike Btree-based LIKE optimization, this works for non-left-anchored
search patterns.  The effectiveness of the search depends on how many
trigrams can be extracted from the pattern.  (The worst case, with no
trigrams, degrades to a full-table scan, so this isn't a panacea.  But
it can be very useful.)

Alexander Korotkov, reviewed by Jan Urbanski
2011-01-31 21:34:49 -05:00
Tom Lane
b525bf771e Add KNNGIST support to contrib/pg_trgm.
Teodor Sigaev, with some revision by Tom
2010-12-04 00:16:21 -05:00
Magnus Hagander
9f2e211386 Remove cvs keywords from all files. 2010-09-20 22:08:53 +02:00
Bruce Momjian
d747140279 8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef list
provided by Andrew.
2009-06-11 14:49:15 +00:00
Teodor Sigaev
b87b52bf04 Support of multibyte encoding for pg_trgm 2008-11-12 13:43:54 +00:00
Andrew Dunstan
53972b460c Add $PostgreSQL$ markers to a lot of files that were missing them.
This particular batch was just for *.c and *.h file.

The changes were made with the following 2 commands:

find . \( \( -name 'libstemmer' -o -name 'expected' -o -name 'ppport.h' \) -prune \) -o  \( -name '*.[ch]'  \) \( -exec grep -q '\$PostgreSQL' {} \; -o -print \) | while read file ; do head -n 1 < $file | grep -q '^/\*' && echo $file; done | xargs -l sed -i -e '1s/^\// /' -e '1i/*\n * $PostgreSQL:$ \n *'

find . \( \( -name 'libstemmer' -o -name 'expected' -o -name 'ppport.h' \) -prune \) -o  \( -name '*.[ch]'  \) \( -exec grep -q '\$PostgreSQL' {} \; -o -print \) | xargs -l sed -i -e '1i/*\n * $PostgreSQL:$ \n */'
2008-05-17 01:28:26 +00:00
Tom Lane
4f09b55dc3 Simplify overly-cute array coding to avoid an apparent gcc bug, which
may or may not be harmless.  Report from Stefan, patch from Heikki.
2007-07-12 23:10:57 +00:00
Tom Lane
9f652d430f Fix up several contrib modules that were using varlena datatypes in not-so-obvious
ways.  I'm not totally sure that I caught everything, but at least now they pass
their regression tests with VARSIZE/SET_VARSIZE defined to reverse byte order.
2007-02-28 22:44:38 +00:00
Tom Lane
234a02b2a8 Replace direct assignments to VARATT_SIZEP(x) with SET_VARSIZE(x, len).
Get rid of VARATT_SIZE and VARATT_DATA, which were simply redundant with
VARSIZE and VARDATA, and as a consequence almost no code was using the
longer names.  Rename the length fields of struct varlena and various
derived structures to catch anyplace that was accessing them directly;
and clean up various places so caught.  In itself this patch doesn't
change any behavior at all, but it is necessary infrastructure if we hope
to play any games with the representation of varlena headers.
Greg Stark and Tom Lane
2007-02-27 23:48:10 +00:00
Neil Conway
8ff2bccee3 Squelch some VC++ compiler warnings. Mark float literals with the "f"
suffix, to distinguish them from doubles. Make some function declarations
and definitions use the "const" qualifier for arguments consistently.
Ignore warning 4102 ("unreferenced label"), because such warnings
are always emitted by bison-generated code. Patch from Magnus Hagander.
2007-01-26 17:45:42 +00:00
Tom Lane
a0ffab351e Magic blocks don't do us any good unless we use 'em ... so install one
in every shared library.
2006-05-30 22:12:16 +00:00
Neil Conway
8e5a10d46c This patch makes the error message strings throughout the backend
more compliant with the error message style guide. In particular,
errdetail should begin with a capital letter and end with a period,
whereas errmsg should not. I also fixed a few related issues in
passing, such as fixing the repeated misspelling of "lexeme" in
contrib/tsearch2 (per Tom's suggestion).
2006-03-01 06:30:32 +00:00
Bruce Momjian
1dc3498251 Standard pgindent run for 8.1. 2005-10-15 02:49:52 +00:00
Bruce Momjian
b6b71b85bc Pgindent run for 8.0. 2004-08-29 05:07:03 +00:00
Teodor Sigaev
cbfa4092bb trgm - Trigram matching for PostgreSQL
--------------------------------------

	The pg_trgm contrib module provides functions and index classes
	for determining the similarity of text based on trigram
	matching.
2004-05-31 17:18:12 +00:00