Add a couple of lines to make it explicit that indexes, constraints,
triggers are added, removed, or left alone.
Backpatch to pg11.
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20200421162038.GA18628@alvherre.pgsql
The original implementation disallowed using OVERRIDING USER VALUE on
identity columns defined as GENERATED ALWAYS, which is not per
standard. So allow that now.
Expand documentation and tests around this.
Author: Dean Rasheed <dean.a.rasheed@gmail.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Reviewed-by: Vik Fearing <vik@postgresfriends.org>
Discussion: https://www.postgresql.org/message-id/flat/CAEZATCVrh2ufCwmzzM%3Dk_OfuLhTTPBJCdFkimst2kry4oHepuQ%40mail.gmail.com
Traditionally autovacuum has only ever invoked a worker based on the
estimated number of dead tuples in a table and for anti-wraparound
purposes. For the latter, with certain classes of tables such as
insert-only tables, anti-wraparound vacuums could be the first vacuum that
the table ever receives. This could often lead to autovacuum workers being
busy for extended periods of time due to having to potentially freeze
every page in the table. This could be particularly bad for very large
tables. New clusters, or recently pg_restored clusters could suffer even
more as many large tables may have the same relfrozenxid, which could
result in large numbers of tables requiring an anti-wraparound vacuum all
at once.
Here we aim to reduce the work required by anti-wraparound and aggressive
vacuums in general, by triggering autovacuum when the table has received
enough INSERTs. This is controlled by adding two new GUCs and reloptions;
autovacuum_vacuum_insert_threshold and
autovacuum_vacuum_insert_scale_factor. These work exactly the same as the
existing scale factor and threshold controls, only base themselves off the
number of inserts since the last vacuum, rather than the number of dead
tuples. New controls were added rather than reusing the existing
controls, to allow these new vacuums to be tuned independently and perhaps
even completely disabled altogether, which can be done by setting
autovacuum_vacuum_insert_threshold to -1.
We make no attempt to skip index cleanup operations on these vacuums as
they may trigger for an insert-mostly table which continually doesn't have
enough dead tuples to trigger an autovacuum for the purpose of removing
those dead tuples. If we were to skip cleaning the indexes in this case,
then it is possible for the index(es) to become bloated over time.
There are additional benefits to triggering autovacuums based on inserts,
as tables which never contain enough dead tuples to trigger an autovacuum
are now more likely to receive a vacuum, which can mark more of the table
as "allvisible" and encourage the query planner to make use of Index Only
Scans.
Currently, we still obey vacuum_freeze_min_age when triggering these new
autovacuums based on INSERTs. For large insert-only tables, it may be
beneficial to lower the table's autovacuum_freeze_min_age so that tuples
are eligible to be frozen sooner. Here we've opted not to zero that for
these types of vacuums, since the table may just be insert-mostly and we
may otherwise freeze tuples that are still destined to be updated or
removed in the near future.
There was some debate to what exactly the new scale factor and threshold
should default to. For now, these are set to 0.2 and 1000, respectively.
There may be some motivation to adjust these before the release.
Author: Laurenz Albe, Darafei Praliaskouski
Reviewed-by: Alvaro Herrera, Masahiko Sawada, Chris Travers, Andres Freund, Justin Pryzby
Discussion: https://postgr.es/m/CAC8Q8t%2Bj36G_bLF%3D%2B0iMo6jGNWnLnWb1tujXuJr-%2Bx8ZCCTqoQ%40mail.gmail.com
Column defaults may be specified separately for each partition.
But INSERT via a partitioned table ignores those partition's default values.
The former is documented, but the latter restriction not.
This commit adds the note about that restriction into the document.
Author: Fujii Masao
Reviewed-by: Amit Langote
Discussion: https://postgr.es/m/CAHGQGwEs-59omrfGF7hOHz9iMME3RbKy5ny+iftDx3LHTEn9sA@mail.gmail.com
a96c41f has introduced the option for heap, but it still lacked the
variant to control the behavior for toast relations.
While on it, refactor the tests so as they stress more scenarios with
the various values that vacuum_index_cleanup can use. It would be
useful to couple those tests with pageinspect to check that pages are
actually cleaned up, but this is left for later.
Author: Masahiko Sawada, Michael Paquier
Reviewed-by: Peter Geoghegan
Discussion: https://postgr.es/m/CAD21AoCqs8iN04RX=i1KtLSaX5RrTEM04b7NHYps4+rqtpWNEg@mail.gmail.com
This commit adds new parameter to VACUUM command, TRUNCATE,
which specifies that VACUUM should attempt to truncate off
any empty pages at the end of the table and allow the disk space
for the truncated pages to be returned to the operating system.
This parameter, if specified, overrides the vacuum_truncate
reloption. If neither the reloption nor the VACUUM option is
used, the default is true, as before.
Author: Fujii Masao
Reviewed-by: Julien Rouhaud, Masahiko Sawada
Discussion: https://postgr.es/m/CAD21AoD+qtrSDL=GSma4Wd3kLYLeRC0hPna-YAdkDeV4z156vg@mail.gmail.com
Commit ca4103025d left a few loose ends. The most important one
(broken pg_dump output) is already fixed by virtue of commit
3b23552ad8, but some things remained:
* When ALTER TABLE rewrites tables, the indexes must remain in the
tablespace they were originally in. This didn't work because
index recreation during ALTER TABLE runs manufactured SQL (yuck),
which runs afoul of default_tablespace in competition with the parent
relation tablespace. To fix, reset default_tablespace to the empty
string temporarily, and add the TABLESPACE clause as appropriate.
* Setting a partitioned rel's tablespace to the database default is
confusing; if it worked, it would direct the partitions to that
tablespace regardless of default_tablespace. But in reality it does
not work, and making it work is a larger project. Therefore, throw
an error when this condition is detected, to alert the unwary.
Add some docs and tests, too.
Author: Álvaro Herrera
Discussion: https://postgr.es/m/CAKJS1f_1c260nOt_vBJ067AZ3JXptXVRohDVMLEBmudX1YEx-A@mail.gmail.com
vacuum_truncate controls whether vacuum tries to truncate off
any empty pages at the end of the table. Previously vacuum always
tried to do the truncation. However, the truncation could cause
some problems; for example, ACCESS EXCLUSIVE lock needs to
be taken on the table during the truncation and can cause
the query cancellation on the standby even if hot_standby_feedback
is true. Setting this reloption to false can be helpful to avoid
such problems.
Author: Tsunakawa Takayuki
Reviewed-By: Julien Rouhaud, Masahiko Sawada, Michael Paquier, Kirk Jamison and Fujii Masao
Discussion: https://postgr.es/m/CAHGQGwE5UqFqSq1=kV3QtTUtXphTdyHA-8rAj4A=Y+e4kyp3BQ@mail.gmail.com
This commit adds a new reloption, vacuum_index_cleanup, which
controls whether index cleanup is performed for a particular
relation by default. It also adds a new option to the VACUUM
command, INDEX_CLEANUP, which can be used to override the
reloption. If neither the reloption nor the VACUUM option is
used, the default is true, as before.
Masahiko Sawada, reviewed and tested by Nathan Bossart, Alvaro
Herrera, Kyotaro Horiguchi, Darafei Praliaskouski, and me.
The wording of the documentation is mostly due to me.
Discussion: http://postgr.es/m/CAD21AoAt5R3DNUZSjOoXDUY=naYPUOuffVsRzuTYMz29yLzQCA@mail.gmail.com
This adds documentation about the user oriented parts of table access
methods (i.e. the default_table_access_method GUC and the USING clause
for CREATE TABLE etc), adds a basic chapter about the table access
method interface, and adds a note to storage.sgml that it's contents
don't necessarily apply for non-builtin AMs.
Author: Haribabu Kommi and Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
Previously, while primary keys could be made on partitioned tables, it
was not possible to define foreign keys that reference those primary
keys. Now it is possible to do that.
Author: Álvaro Herrera
Reviewed-by: Amit Langote, Jesper Pedersen
Discussion: https://postgr.es/m/20181102234158.735b3fevta63msbj@alvherre.pgsql
This is an SQL-standard feature that allows creating columns that are
computed from expressions rather than assigned, similar to a view or
materialized view but on a column basis.
This implements one kind of generated column: stored (computed on
write). Another kind, virtual (computed on read), is planned for the
future, and some room is left for it.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/b151f851-4019-bdb1-699e-ebab07d2f40a@2ndquadrant.com
Column references are not allowed in default expressions and partition
bound expressions, and are restricted as such once the transformation of
their expressions is done. However, trying to use more complex column
references can lead to confusing error messages. For example, trying to
use a two-field column reference name for default expressions and
partition bounds leads to "missing FROM-clause entry for table", which
makes no sense in their respective context.
In order to make the errors generated more useful, this commit adds more
verbose messages when transforming column references depending on the
context. This has a little consequence though: for example an
expression using an aggregate with a column reference as argument would
cause an error to be generated for the column reference, while the
aggregate was the problem reported before this commit because column
references get transformed first.
The confusion exists for default expressions for a long time, and the
problem is new as of v12 for partition bounds. Still per the lack of
complaints on the matter no backpatch is done.
The patch has been written by Amit Langote and me, and Tom Lane has
provided the improvement of the documentation for default expressions on
the CREATE TABLE page.
Author: Amit Langote, Michael Paquier
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/20190326020853.GM2558@paquier.xyz
This change makes it possible to specify sub-millisecond delays,
which work well on most modern platforms, though that was not true
when the cost-delay feature was designed.
To support this without breaking existing configuration entries,
improve guc.c to allow floating-point GUCs to have units. Also,
allow "us" (microseconds) as an input/output unit for time-unit GUCs.
(It's not allowed as a base unit, at least not yet.)
Likewise change the autovacuum_vacuum_cost_delay reloption to be
floating-point; this forces a catversion bump because the layout of
StdRdOptions changes.
This patch doesn't in itself change the default values or allowed
ranges for these parameters, and it should not affect the behavior
for any already-allowed setting for them.
Discussion: https://postgr.es/m/1798.1552165479@sss.pgh.pa.us
Previously, only literals were allowed. This change allows general
expressions, including functions calls, which are evaluated at the
time the DDL command is executed.
Besides offering some more functionality, it simplifies the parser
structures and removes some inconsistencies in how the literals were
handled.
Author: Kyotaro Horiguchi, Tom Lane, Amit Langote
Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/9f88b5e0-6da2-5227-20d0-0d7012beaa1c@lab.ntt.co.jp/
The documentation of ON DELETE and ON UPDATE uses the term "action",
which is also used on the ALTER TABLE page for other purposes. This
commit renames the term to "referential_action", which is more
consistent with the SQL specification. The new term is now used on the
documentation of both CREATE TABLE and ALTER TABLE for consistency.
Reported-by: Brigitte Blanc-Lafay
Author: Lætitia Avrot
Reviewed-by: Álvaro Herrera
Discussion: https://postgr.es/m/CAB_COdiHEVVs0uB+uYCjjYUwQ4YFFekppq+Xqv6qAM8+cd42gA@mail.gmail.com
When partitioned tables were introduced, we failed to realize that by
copying the tablespace handling for other relation kinds with no
physical storage we were causing the secondary effect that their
partitions would not automatically inherit the tablespace setting. This
is surprising and unhelpful, so change it to adopt the behavior
introduced in pg11 (commit 33e6c34c32) for partitioned indexes: the
parent relation remembers the tablespace specification, which is then
used for any new partitions that don't declare one.
Because this commit changes behavior of the TABLESPACE clause for
partitioned tables (it's no longer a no-op), it is not backpatched.
Author: David Rowley, Álvaro Herrera
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/CAKJS1f9SxVzqDrGD1teosFd6jBMM0UEaa14_8mRvcWE19Tu0hA@mail.gmail.com
Previously tables declared WITH OIDS, including a significant fraction
of the catalog tables, stored the oid column not as a normal column,
but as part of the tuple header.
This special column was not shown by default, which was somewhat odd,
as it's often (consider e.g. pg_class.oid) one of the more important
parts of a row. Neither pg_dump nor COPY included the contents of the
oid column by default.
The fact that the oid column was not an ordinary column necessitated a
significant amount of special case code to support oid columns. That
already was painful for the existing, but upcoming work aiming to make
table storage pluggable, would have required expanding and duplicating
that "specialness" significantly.
WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0).
Remove it.
Removing includes:
- CREATE TABLE and ALTER TABLE syntax for declaring the table to be
WITH OIDS has been removed (WITH (oids[ = true]) will error out)
- pg_dump does not support dumping tables declared WITH OIDS and will
issue a warning when dumping one (and ignore the oid column).
- restoring an pg_dump archive with pg_restore will warn when
restoring a table with oid contents (and ignore the oid column)
- COPY will refuse to load binary dump that includes oids.
- pg_upgrade will error out when encountering tables declared WITH
OIDS, they have to be altered to remove the oid column first.
- Functionality to access the oid of the last inserted row (like
plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed.
The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false)
for CREATE TABLE) is still supported. While that requires a bit of
support code, it seems unnecessary to break applications / dumps that
do not use oids, and are explicit about not using them.
The biggest user of WITH OID columns was postgres' catalog. This
commit changes all 'magic' oid columns to be columns that are normally
declared and stored. To reduce unnecessary query breakage all the
newly added columns are still named 'oid', even if a table's column
naming scheme would indicate 'reloid' or such. This obviously
requires adapting a lot code, mostly replacing oid access via
HeapTupleGetOid() with access to the underlying Form_pg_*->oid column.
The bootstrap process now assigns oids for all oid columns in
genbki.pl that do not have an explicit value (starting at the largest
oid previously used), only oids assigned later by oids will be above
FirstBootstrapObjectId. As the oid column now is a normal column the
special bootstrap syntax for oids has been removed.
Oids are not automatically assigned during insertion anymore, all
backend code explicitly assigns oids with GetNewOidWithIndex(). For
the rare case that insertions into the catalog via SQL are called for
the new pg_nextoid() function can be used (which only works on catalog
tables).
The fact that oid columns on system tables are now normal columns
means that they will be included in the set of columns expanded
by * (i.e. SELECT * FROM pg_class will now include the table's oid,
previously it did not). It'd not technically be hard to hide oid
column by default, but that'd mean confusing behavior would either
have to be carried forward forever, or it'd cause breakage down the
line.
While it's not unlikely that further adjustments are needed, the
scope/invasiveness of the patch makes it worthwhile to get merge this
now. It's painful to maintain externally, too complicated to commit
after the code code freeze, and a dependency of a number of other
patches.
Catversion bump, for obvious reasons.
Author: Andres Freund, with contributions by John Naylor
Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
This commit fixes a set of issues with ON COMMIT actions when used on
partitioned tables and tables with inheritance children:
- Applying ON COMMIT DROP on a partitioned table with partitions or on a
table with inheritance children caused a failure at commit time, with
complains about the children being already dropped as all relations are
dropped one at the same time.
- Applying ON COMMIT DELETE on a partition relying on a partitioned
table which uses ON COMMIT DROP would cause the partition truncation to
fail as the parent is removed first.
The solution to the first problem is to handle the removal of all the
dependencies in one go instead of dropping relations one-by-one, based
on a suggestion from Álvaro Herrera. So instead all the relation OIDs
to remove are gathered and then processed in one round of multiple
deletions.
The solution to the second problem is to reorder the actions, with
truncation happening first and relation drop done after. Even if it
means that a partition could be first truncated, then immediately
dropped if its partitioned table is dropped, this has the merit to keep
the code simple as there is no need to do existence checks on the
relations to drop.
Contrary to a manual TRUNCATE on a partitioned table, ON COMMIT DELETE
does not cascade to its partitions. The ON COMMIT action defined on
each partition gets the priority.
Author: Michael Paquier
Reviewed-by: Amit Langote, Álvaro Herrera, Robert Haas
Discussion: https://postgr.es/m/68f17907-ec98-1192-f99f-8011400517f5@lab.ntt.co.jp
Backpatch-through: 10
It's been true for a long time that we expect names of table and domain
constraints to be unique among the constraints of that table or domain.
However, the enforcement of that has been pretty haphazard, and it missed
some corner cases such as creating a CHECK constraint and then an index
constraint of the same name (as per recent report from André Hänsel).
Also, due to the lack of an actual unique index enforcing this, duplicates
could be created through race conditions.
Moreover, the code that searches pg_constraint has been quite inconsistent
about how to handle duplicate names if one did occur: some places checked
and threw errors if there was more than one match, while others just
processed the first match they came to.
To fix, create a unique index on (conrelid, contypid, conname). Since
either conrelid or contypid is zero, this will separately enforce
uniqueness of constraint names among constraints of any one table and any
one domain. (If we ever implement SQL assertions, and put them into this
catalog, more thought might be needed. But it'd be at least as reasonable
to put them into a new catalog; having overloaded this one catalog with
two kinds of constraints was a mistake already IMO.) This index can replace
the existing non-unique index on conrelid, though we need to keep the one
on contypid for query performance reasons.
Having done that, we can simplify the logic in various places that either
coped with duplicates or neglected to, as well as potentially improve
lookup performance when searching for a constraint by name.
Also, as per our usual practice, install a preliminary check so that you
get something more friendly than a unique-index violation report in the
case complained of by André. And teach ChooseIndexName to avoid choosing
autogenerated names that would draw such a failure.
While it's not possible to make such a change in the back branches,
it doesn't seem quite too late to put this into v11, so do so.
Discussion: https://postgr.es/m/0c1001d4428f$0942b430$1bc81c90$@webkr.de
The initial version of the included-index-column feature stated that
included columns couldn't be the same as any key column of the index.
While it'd be pretty silly to do that, since the included column would be
entirely redundant, we've never prohibited redundant index columns before
so it's not very consistent to do so here. Moreover, the prohibition
was itself badly implemented, so that it failed to reject columns that
were effectively identical but not spelled quite alike, as reported by
Aditya Toshniwal.
(Moreover, it's not hard to imagine that for some non-btree index types,
such cases would be non-silly anyhow: the index might use a lossy
representation for key columns but be able to support retrieval of the
original form of included columns.)
Hence, let's just drop the prohibition.
In passing, do some copy-editing on the documentation for the
included-column feature.
Yugo Nagata; documentation and test corrections by me
Discussion: https://postgr.es/m/CAM9w-_mhBCys4fQNfaiQKTRrVWtoFrZ-wXmDuE9Nj5y-Y7aDKQ@mail.gmail.com
It's more logical this way, since the new ordering matches the way the
tables are created; but in any case, the previous location of PARTITION OF
did not appear carefully chosen anyway (since it didn't match the
location in which it appears in the synopsys either, which is what we
normally do.)
In the PARTITION BY stanza, add a link to the partitioning section in
the DDL chapter, too.
Suggested-by: David G. Johnston
Discussion: https://postgr.es/m/CAKFQuwY4Ld7ecxL_KAmaxwt0FUu5VcPPN2L4dh+3BeYbrdBa5g@mail.gmail.com
This section once started out small but has now grown quite a bit and
needs a bit of structure.
Rewrite as list, add documentation of EXCLUDING, and improve the
documentation of INCLUDING ALL instead of just listing all the options
again.
per report from Yugo Nagata that EXCLUDING was not documented, that part
reviewed by Daniel Gustafsson, most of the rewrite was by me
Previously, you could partition by a boolean column as long as you
spelled the bound values as string literals, for instance FOR VALUES
IN ('t'). The trouble with this is that ruleutils.c printed that as
FOR VALUES IN (TRUE), which is reasonable syntax but wasn't accepted by
the grammar. That results in dump-and-reload failures for such cases.
Apply a minimal fix that just causes TRUE and FALSE to be converted to
strings 'true' and 'false'. This is pretty grotty, but it's too late for
a more principled fix in v11 (to say nothing of v10). We should revisit
the whole issue of how partition bound values are parsed for v12.
Amit Langote
Discussion: https://postgr.es/m/e05c5162-1103-7e37-d1ab-6de3e0afaf70@lab.ntt.co.jp
This patch introduces INCLUDE clause to index definition. This clause
specifies a list of columns which will be included as a non-key part in
the index. The INCLUDE columns exist solely to allow more queries to
benefit from index-only scans. Also, such columns don't need to have
appropriate operator classes. Expressions are not supported as INCLUDE
columns since they cannot be used in index-only scans.
Index access methods supporting INCLUDE are indicated by amcaninclude flag
in IndexAmRoutine. For now, only B-tree indexes support INCLUDE clause.
In B-tree indexes INCLUDE columns are truncated from pivot index tuples
(tuples located in non-leaf pages and high keys). Therefore, B-tree indexes
now might have variable number of attributes. This patch also provides
generic facility to support that: pivot tuples contain number of their
attributes in t_tid.ip_posid. Free 13th bit of t_info is used for indicating
that. This facility will simplify further support of index suffix truncation.
The changes of above are backward-compatible, pg_upgrade doesn't need special
handling of B-tree indexes for that.
Bump catalog version
Author: Anastasia Lubennikova with contribition by Alexander Korotkov and me
Reviewed by: Peter Geoghegan, Tomas Vondra, Antonin Houska, Jeff Janes,
David Rowley, Alexander Korotkov
Discussion: https://www.postgresql.org/message-id/flat/56168952.4010101@postgrespro.ru
The LIKE INCLUDING ALL clause to CREATE TABLE intuitively indicates
cloning of extended statistics on the source table, but it failed to do
so. Patch it up so that it does. Also include an INCLUDING STATISTICS
option to the LIKE clause, so that the behavior can be requested
individually, or excluded individually.
While at it, reorder the INCLUDING options, both in code and in docs, in
alphabetical order which makes more sense than feature-implementation
order that was previously used.
Backpatch this to Postgres 10, where extended statistics were
introduced, because this is seen as an oversight in a fresh feature
which is better to get consistent from the get-go instead of changing
only in pg11.
In pg11, comments on statistics objects are cloned too. In pg10 they
are not, because I (Álvaro) was too coward to change the parse node as
required to support it. Also, in pg10 I chose not to renumber the
parser symbols for the various INCLUDING options in LIKE, for the same
reason. Any corresponding user-visible changes (docs) are backpatched,
though.
Reported-by: Stephen Froehlich
Author: David Rowley
Reviewed-by: Álvaro Herrera, Tomas Vondra
Discussion: https://postgr.es/m/CY1PR0601MB1927315B45667A1B679D0FD5E5EF0@CY1PR0601MB1927.namprd06.prod.outlook.com
If we restrict unique constraints on partitioned tables so that they
must always include the partition key, then our standard approach to
unique indexes already works --- each unique key is forced to exist
within a single partition, so enforcing the unique restriction in each
index individually is enough to have it enforced globally. Therefore we
can implement unique indexes on partitions by simply removing a few
restrictions (and adding others.)
Discussion: https://postgr.es/m/20171222212921.hi6hg6pem2w2t36z@alvherre.pgsql
Discussion: https://postgr.es/m/20171229230607.3iib6b62fn3uaf47@alvherre.pgsql
Reviewed-by: Simon Riggs, Jesper Pedersen, Peter Eisentraut, Jaime
Casanova, Amit Langote
To make this work, tuplesort.c and logtape.c must also support
parallelism, so this patch adds that infrastructure and then applies
it to the particular case of parallel btree index builds. Testing
to date shows that this can often be 2-3x faster than a serial
index build.
The model for deciding how many workers to use is fairly primitive
at present, but it's better than not having the feature. We can
refine it as we get more experience.
Peter Geoghegan with some help from Rushabh Lathia. While Heikki
Linnakangas is not an author of this patch, he wrote other patches
without which this feature would not have been possible, and
therefore the release notes should possibly credit him as an author
of this feature. Reviewed by Claudio Freire, Heikki Linnakangas,
Thomas Munro, Tels, Amit Kapila, me.
Discussion: http://postgr.es/m/CAM3SWZQKM=Pzc=CAHzRixKjp2eO5Q0Jg1SoFQqeXFQ647JiwqQ@mail.gmail.com
Discussion: http://postgr.es/m/CAH2-Wz=AxWqDoVvGU7dq856S4r6sJAj6DBn7VMtigkB33N5eyg@mail.gmail.com
Since some preparation work had already been done, the only source
changes left were changing empty-element tags like <xref linkend="foo">
to <xref linkend="foo"/>, and changing the DOCTYPE.
The source files are still named *.sgml, but they are actually XML files
now. Renaming could be considered later.
In the build system, the intermediate step to convert from SGML to XML
is removed. Everything is build straight from the source files again.
The OpenSP (or the old SP) package is no longer needed.
The documentation toolchain instructions are updated and are much
simpler now.
Peter Eisentraut, Alexander Lakhin, Jürgen Purtz
Hash partitioning is useful when you want to partition a growing data
set evenly. This can be useful to keep table sizes reasonable, which
makes maintenance operations such as VACUUM faster, or to enable
partition-wise join.
At present, we still depend on constraint exclusion for partitioning
pruning, and the shape of the partition constraints for hash
partitioning is such that that doesn't work. Work is underway to fix
that, which should both improve performance and make partitioning
pruning work with hash partitioning.
Amul Sul, reviewed and tested by Dilip Kumar, Ashutosh Bapat, Yugo
Nagata, Rajkumar Raghuwanshi, Jesper Pedersen, and by me. A few
final tweaks also by me.
Discussion: http://postgr.es/m/CAAJ_b96fhpJAP=ALbETmeLk1Uni_GFZD938zgenhF49qgDTjaQ@mail.gmail.com
IDs in SGML are case insensitive, and we have accumulated a mix of upper
and lower case IDs, including different variants of the same ID. In
XML, these will be case sensitive, so we need to fix up those
differences. Going to all lower case seems most straightforward, and
the current build process already makes all anchors and lower case
anyway during the SGML->XML conversion, so this doesn't create any
difference in the output right now. A future XML-only build process
would, however, maintain any mixed case ID spellings in the output, so
that is another reason to clean this up beforehand.
Author: Alexander Lakhin <exclusion@gmail.com>
Alvaro Herrera
Peter Eisentraut
David Rowley
Michael Paquier
Fujii Masao
Thomas Munro
Robert Haas
Andres Freund
Tom Lane
Peter Eisentraut
Heikki Linnakangas
Teodor Sigaev
Simon Riggs