access/heapam contains functions that are very storage specific (say
heap_insert() and a lot of lower level functions), and fairly generic
infrastructure like relation_open(), heap_open() etc. In the upcoming
pluggable storage work we're introducing a layer between table
accesses in general and heapam, to allow for different storage
methods. For a bit cleaner separation it thus seems advantageous to
move generic functions like the aforementioned to their own headers.
access/relation.h will contain relation_open() etc, and access/table.h
will contain table_open() (formerly known as heap_open()). I've decided
for table.h not to include relation.h, but we might change that at a
later stage.
relation.h already exists in another directory, but the other
plausible name (rel.h) also conflicts. It'd be nice if there were a
non-conflicting name, but nobody came up with a suggestion. It's
possible that the appropriate way to address the naming conflict would
be to rename nodes/relation.h, which isn't particularly well named.
To avoid breaking a lot of extensions that just use heap_open() etc,
table.h has macros mapping the old names to the new ones, and heapam.h
includes relation, table.h. That also allows to keep the
bulk renaming of existing callers in a separate commit.
Author: Andres Freund
Discussion: https://postgr.es/m/20190111000539.xbv7s6w7ilcvm7dp@alap3.anarazel.de
Add a TABLESAMPLE clause to SELECT statements that allows
user to specify random BERNOULLI sampling or block level
SYSTEM sampling. Implementation allows for extensible
sampling functions to be written, using a standard API.
Basic version follows SQLStandard exactly. Usable
concrete use cases for the sampling API follow in later
commits.
Petr Jelinek
Reviewed by Michael Paquier and Simon Riggs
BRIN is a new index access method intended to accelerate scans of very
large tables, without the maintenance overhead of btrees or other
traditional indexes. They work by maintaining "summary" data about
block ranges. Bitmap index scans work by reading each summary tuple and
comparing them with the query quals; all pages in the range are returned
in a lossy TID bitmap if the quals are consistent with the values in the
summary tuple, otherwise not. Normal index scans are not supported
because these indexes do not store TIDs.
As new tuples are added into the index, the summary information is
updated (if the block range in which the tuple is added is already
summarized) or not; in the latter case, a subsequent pass of VACUUM or
the brin_summarize_new_values() function will create the summary
information.
For data types with natural 1-D sort orders, the summary info consists
of the maximum and the minimum values of each indexed column within each
page range. This type of operator class we call "Minmax", and we
supply a bunch of them for most data types with B-tree opclasses.
Since the BRIN code is generalized, other approaches are possible for
things such as arrays, geometric types, ranges, etc; even for things
such as enum types we could do something different than minmax with
better results. In this commit I only include minmax.
Catalog version bumped due to new builtin catalog entries.
There's more that could be done here, but this is a good step forwards.
Loosely based on ideas from Simon Riggs; code mostly by Álvaro Herrera,
with contribution by Heikki Linnakangas.
Patch reviewed by: Amit Kapila, Heikki Linnakangas, Robert Haas.
Testing help from Jeff Janes, Erik Rijkers, Emanuel Calvo.
PS:
The research leading to these results has received funding from the
European Union's Seventh Framework Programme (FP7/2007-2013) under
grant agreement n° 318633.
SP-GiST is comparable to GiST in flexibility, but supports non-balanced
partitioned search structures rather than balanced trees. As described at
PGCon 2011, this new indexing structure can beat GiST in both index build
time and query speed for search problems that it is well matched to.
There are a number of areas that could still use improvement, but at this
point the code seems committable.
Teodor Sigaev and Oleg Bartunov, with considerable revisions by Tom Lane
Subject: [PORTS] Patches for Irix 6.4
I have worked out how to compile PostgreSQL on Irix 6.4 using the -n32 compiler
mode and version 7.1 of the C compiler. (The n32 compiler use 32 bits
addressing,
but allows access to all the instructions in the MIPS4 instruction set.)
There were several problems:
1) The ld command is not referenced as a macro in all the Makefiles. On
this platform, you have to include -n32 on all the ld commands. Makefiles
were changed as needed.
3) Lots of warnings are generated from the compiler. Since the regression
tests worked OK, I didn't attempt to fix them. If anyone wants the compilation
log, please let me know, and I'll email it to you.
The version of postgresql was 970602. Here is Makefile.custom:
CUSTOM_COPT = -O2 -n32
MK_NO_LORDER = 1
LD = ld -n32
CC += -n32
Andres Freund
Simon Riggs
Alvaro Herrera
Tom Lane
Magnus Hagander
Peter Eisentraut
Teodor Sigaev
PostgreSQL Daemon
Bruce Momjian
Marc G. Fournier
Bryan Henderson