If there is no positional information of lexemes then phrase operator will not
fallback to AND operator. This change makes needing to modify TS_execute()
interface, because somewhere (in indexes, for example) positional information
is unaccesible and in this cases we need to force fallback to AND.
Per discussion c19fcfec308e6ccd952cdde9e648b505@mail.gmail.com
Patch introduces new text search operator (<-> or <DISTANCE>) into tsquery.
On-disk and binary in/out format of tsquery are backward compatible.
It has two side effect:
- change order for tsquery, so, users, who has a btree index over tsquery,
should reindex it
- less number of parenthesis in tsquery output, and tsquery becomes more
readable
Authors: Teodor Sigaev, Oleg Bartunov, Dmitry Ivanov
Reviewers: Alexander Korotkov, Artur Zakirov
Commits 9ff60273e3 and dbe2328959 adjusted the declarations
of some core functions referenced by contrib/tsearch2's install script,
forgetting that in a pg_upgrade situation, we'll be trying to restore
operator class definitions that reference the old signatures. We've
hit this problem before; solve it in the same way as before, namely by
installing stub functions that have the expected signature and just
invoke the correct function. Per report from Jeff Janes.
(Someday we ought to stop supporting contrib/tsearch2, but I'm not
sure today is that day.)
Now that we use CRC-32C in WAL and the control file, the "traditional" and
"legacy" CRC-32 variants are not used in any frontend programs anymore.
Move the code for those back from src/common to src/backend/utils/hash.
Also move the slicing-by-8 implementation (back) to src/port. This is in
preparation for next patch that will add another implementation that uses
Intel SSE 4.2 instructions to calculate CRC-32C, where available.
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.
The latter was already the dominant use, and it's preferable because
in C the convention is that intXX means XX bits. Therefore, allowing
mixed use of int2, int4, int8, int16, int32 is obviously confusing.
Remove the typedefs for int2 and int4 for now. They don't seem to be
widely used outside of the PostgreSQL source tree, and the few uses
can probably be cleaned up by the time this ships.
This addresses only those cases that are easy to fix by adding or
moving a const qualifier or removing an unnecessary cast. There are
many more complicated cases remaining.
"consistent" functions, and remove pg_amop.opreqcheck, as per recent
discussion. The main immediate benefit of this is that we no longer need
8.3's ugly hack of requiring @@@ rather than @@ to test weight-using tsquery
searches on GIN indexes. In future it should be possible to optimize some
other queries better than is done now, by detecting at runtime whether the
index match is exact or not.
Tom Lane, after an idea of Heikki's, and with some help from Teodor.
* Defined new struct WordEntryPosVector that holds a uint16 length and a
variable size array of WordEntries. This replaces the previous
convention of a variable size uint16 array, with the first element
implying the length. WordEntryPosVector has the same layout in memory,
but is more readable in source code. The POSDATAPTR and POSDATALEN
macros are still used, though it would now be more readable to access
the fields in WordEntryPosVector directly.
* Removed needfree field from DocRepresentation. It was always set to false.
* Miscellaneous other commenting and refactoring
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.
Oleg Bartunov and Teodor Sigaev, but I did a lot of editorializing,
so anything that's broken is probably my fault.
Documentation is nonexistent as yet, but let's land the patch so we can
get some portability testing done.
Teodor Sigaev
Tom Lane
Bruce Momjian
Heikki Linnakangas
Robert Haas
Peter Eisentraut
Magnus Hagander