Since the existing bit number argument can't exceed INT32_MAX, it's
not possible for these functions to manipulate bits beyond the first
256MB of a bytea value. Lift that restriction by redeclaring the
bit number arguments as int8 (which requires a catversion bump,
hence is not back-patchable).
The similarly-named functions for bit/varbit don't really have a
problem because we restrict those types to at most VARBITMAXLEN bits;
hence leave them alone.
While here, extend the encode/decode functions in utils/adt/encode.c
to allow dealing with values wider than 1GB. This is not a live bug
or restriction in current usage, because no input could be more than
1GB, and since none of the encoders can expand a string more than 4X,
the result size couldn't overflow uint32. But it might be desirable
to support more in future, so make the input length values size_t
and the potential-output-length values uint64.
Also add some test cases to improve the miserable code coverage
of these functions.
Movead Li, editorialized some by me; also reviewed by Ashutosh Bapat
Discussion: https://postgr.es/m/20200312115135445367128@highgo.ca
Commit d2d8a229bc introduced Incremental Sort, but it was considered
only in create_ordered_paths() as an alternative to regular Sort. There
are many other places that require sorted input and might benefit from
considering Incremental Sort too.
This patch modifies a number of those places, but not all. The concern
is that just adding Incremental Sort to any place that already adds
Sort may increase the number of paths considered, negatively affecting
planning time, without any benefit. So we've taken a more conservative
approach, based on analysis of which places do affect a set of queries
that did seem practical. This means some less common queries may not
benefit from Incremental Sort yet.
Author: Tomas Vondra
Reviewed-by: James Coleman
Discussion: https://postgr.es/m/CAPpHfds1waRZ=NOmueYq0sx1ZSCnt+5QJvizT8ndT2=etZEeAQ@mail.gmail.com
The txid_XXX family of fmgr functions exposes 64 bit transaction IDs to
users as int8. Now that we have an SQL type xid8 for FullTransactionId,
define a new set of functions including pg_current_xact_id() and
pg_current_snapshot() based on that. Keep the old functions around too,
for now.
It's a bit sneaky to use the same C functions for both, but since the
binary representation is identical except for the signedness of the
type, and since older functions are the ones using the wrong signedness,
and since we'll presumably drop the older ones after a reasonable period
of time, it seems reasonable to switch to FullTransactionId internally
and share the code for both.
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Takao Fujii <btfujiitkp@oss.nttdata.com>
Reviewed-by: Yoshikazu Imai <imai.yoshikazu@fujitsu.com>
Reviewed-by: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://postgr.es/m/20190725000636.666m5mad25wfbrri%40alap3.anarazel.de
Similar to xid, but 64 bits wide. This new type is suitable for use in
various system views and administration functions.
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Takao Fujii <btfujiitkp@oss.nttdata.com>
Reviewed-by: Yoshikazu Imai <imai.yoshikazu@fujitsu.com>
Reviewed-by: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://postgr.es/m/20190725000636.666m5mad25wfbrri%40alap3.anarazel.de
Incremental Sort is an optimized variant of multikey sort for cases when
the input is already sorted by a prefix of the requested sort keys. For
example when the relation is already sorted by (key1, key2) and we need
to sort it by (key1, key2, key3) we can simply split the input rows into
groups having equal values in (key1, key2), and only sort/compare the
remaining column key3.
This has a number of benefits:
- Reduced memory consumption, because only a single group (determined by
values in the sorted prefix) needs to be kept in memory. This may also
eliminate the need to spill to disk.
- Lower startup cost, because Incremental Sort produce results after each
prefix group, which is beneficial for plans where startup cost matters
(like for example queries with LIMIT clause).
We consider both Sort and Incremental Sort, and decide based on costing.
The implemented algorithm operates in two different modes:
- Fetching a minimum number of tuples without check of equality on the
prefix keys, and sorting on all columns when safe.
- Fetching all tuples for a single prefix group and then sorting by
comparing only the remaining (non-prefix) keys.
We always start in the first mode, and employ a heuristic to switch into
the second mode if we believe it's beneficial - the goal is to minimize
the number of unnecessary comparions while keeping memory consumption
below work_mem.
This is a very old patch series. The idea was originally proposed by
Alexander Korotkov back in 2013, and then revived in 2017. In 2018 the
patch was taken over by James Coleman, who wrote and rewrote most of the
current code.
There were many reviewers/contributors since 2013 - I've done my best to
pick the most active ones, and listed them in this commit message.
Author: James Coleman, Alexander Korotkov
Reviewed-by: Tomas Vondra, Andreas Karlsson, Marti Raudsepp, Peter Geoghegan, Robert Haas, Thomas Munro, Antonin Houska, Andres Freund, Alexander Kuzmenkov
Discussion: https://postgr.es/m/CAPpHfdscOX5an71nHd8WSUH6GNOCf=V7wgDaTXdDd9=goN-gfA@mail.gmail.com
Discussion: https://postgr.es/m/CAPpHfds1waRZ=NOmueYq0sx1ZSCnt+5QJvizT8ndT2=etZEeAQ@mail.gmail.com
Since commit 8f59f6b9c0, CLOBBER_CACHE_ALWAYS buildfarm members have
been failing this test case because the error message now sometimes
includes an error cursor position. It seems largely just luck that
that never happened before, and there are likely to be more ways it
could happen in future. Hence, rather than trying to prevent it,
adjust the test script to suppress that component of the report.
At some point we might need to back-patch this, but refrain until
there's a demonstrated need. (We'd need a different fix before v12,
anyway, since VERBOSITY=sqlstate is a recent thing.)
Tom Lane and Andres Freund
Discussion: https://postgr.es/m/30675.1586111599@sss.pgh.pa.us
A table rewritten by ALTER TABLE would lose tracking of an index usable
for CLUSTER. This setting is tracked by pg_index.indisclustered and is
controlled by ALTER TABLE, so some extra work was needed to restore it
properly. Note that ALTER TABLE only marks the index that can be used
for clustering, and does not do the actual operation.
Author: Amit Langote, Justin Pryzby
Reviewed-by: Ibrar Ahmed, Michael Paquier
Discussion: https://postgr.es/m/20200202161718.GI13621@telsasoft.com
Backpatch-through: 9.5
Commit 7cb0a423f overlooked that the multi-level partition test table
pagg_tab_ml still had an exactly even row split at its upper level of
partitioning, so that some of the sub-aggregation plan steps still had
exactly equal costs, leading to plan instability. Tweak the partition
boundaries some more to make the row distribution unequal at both
levels. This leads to more changes in the "expected" plan order than
the previous round, but it seems fine. (Actually, I'm surprised that
this didn't affect even more plans in this test: looking at the
underlying costs shows that some of the parallel plan groups are
*not* getting sorted by cost. Bug?)
Per buildfarm member lousyjack,
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=lousyjack&dt=2020-04-04%2021%3A03%3A04
Discussion: https://postgr.es/m/24467.1585838693@sss.pgh.pa.us
Commit 77ec5affb added an assertion to enforce_generic_type_consistency
that boils down to "if the function result is polymorphic, there must be
at least one polymorphic argument". This should be true for user-created
functions, but there are built-in functions for which it's not true, as
pointed out by Jaime Casanova. Hence, go back to the old behavior of
leaving the return type alone. There's only a limited amount of stuff
you can do with such a function result, but it does work to some extent;
add some regression test cases to ensure we don't break that again.
Discussion: https://postgr.es/m/CAJGNTeMbhtsCUZgJJ8h8XxAJbK7U2ipsX8wkHRtZRz-NieT8RA@mail.gmail.com
Until now, only selected bulk operations (e.g. COPY) did this. If a
given relfilenode received both a WAL-skipping COPY and a WAL-logged
operation (e.g. INSERT), recovery could lose tuples from the COPY. See
src/backend/access/transam/README section "Skipping WAL for New
RelFileNode" for the new coding rules. Maintainers of table access
methods should examine that section.
To maintain data durability, just before commit, we choose between an
fsync of the relfilenode and copying its contents to WAL. A new GUC,
wal_skip_threshold, guides that choice. If this change slows a workload
that creates small, permanent relfilenodes under wal_level=minimal, try
adjusting wal_skip_threshold. Users setting a timeout on COMMIT may
need to adjust that timeout, and log_min_duration_statement analysis
will reflect time consumption moving to COMMIT from commands like COPY.
Internally, this requires a reliable determination of whether
RollbackAndReleaseCurrentSubTransaction() would unlink a relation's
current relfilenode. Introduce rd_firstRelfilenodeSubid. Amend the
specification of rd_createSubid such that the field is zero when a new
rel has an old rd_node. Make relcache.c retain entries for certain
dropped relations until end of transaction.
Bump XLOG_PAGE_MAGIC, since this introduces XLOG_GIST_ASSIGN_LSN.
Future servers accept older WAL, so this bump is discretionary.
Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert
Haas. Heikki Linnakangas and Michael Paquier implemented earlier
designs that materially clarified the problem. Reviewed, in earlier
designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane,
Fujii Masao, and Simon Riggs. Reported by Martijn van Oosterhout.
Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
When BUFFERS option is enabled, EXPLAIN command includes the information
on buffer usage during each plan node, in its output. In addition to that,
this commit makes EXPLAIN command include also the information on
buffer usage during planning phase, in its output. This feature makes it
easier to discern the cases where lots of buffer access happen during
planning.
This commit revives the original commit ed7a509571 that was reverted by
commit 19db23bcbd. The original commit had to be reverted because
it caused the regression test failure on the buildfarm members prion and
dory. But since commit c0885c4c30 got rid of the caues of the test failure,
the original commit can be safely introduced again.
Author: Julien Rouhaud, slightly revised by Fujii Masao
Reviewed-by: Justin Pryzby
Discussion: https://postgr.es/m/16109-26a1a88651e90608@postgresql.org
entryGetItem()'s three code paths each contained bugs associated
with filtering the entries for gin_fuzzy_search_limit.
The posting-tree path failed to advance "advancePast" after having
decided to filter an item. If we ran out of items on the current
page and needed to advance to the next, what would actually happen
is that entryLoadMoreItems() would re-load the same page. Eventually,
the random dropItem() test would accept one of the same items it'd
previously rejected, and we'd move on --- but it could take awhile
with small gin_fuzzy_search_limit. To add insult to injury, this
case would inevitably cause entryLoadMoreItems() to decide it needed
to re-descend from the root, making things even slower.
The posting-list path failed to implement gin_fuzzy_search_limit
filtering at all, so that all entries in the posting list would
be returned.
The bitmap-result path used a "gotitem" variable that it failed to
update in the one place where it'd actually make a difference, ie
at the one "continue" statement. I think this was unreachable in
practice, because if we'd looped around then it shouldn't be the
case that the entries on the new page are before advancePast.
Still, the "gotitem" variable was contributing nothing to either
clarity or correctness, so get rid of it.
Refactor all three loops so that the termination conditions are
more alike and less unreadable.
The code coverage report showed that we had no coverage at all for
the re-descend-from-root code path in entryLoadMoreItems(), which
seems like a very bad thing, so add a test case that exercises it.
We also had exactly no coverage for gin_fuzzy_search_limit, so add a
simplistic test case that at least hits those code paths a little bit.
Back-patch to all supported branches.
Adé Heyward and Tom Lane
Discussion: https://postgr.es/m/CAEknJCdS-dE1Heddptm7ay2xTbSeADbkaQ8bU2AXRCVC2LdtKQ@mail.gmail.com
The explain regression test runs EXPLAIN commands via the function
that filters unstable outputs. To produce more stable test output,
this commit improves the function so that it also filters out text-mode
Buffers lines. This is necessary because text-mode Buffers lines vary
depending the system state.
This improvement will get rid of the regression test failure that
the commit ed7a509571 caused on the buildfarm members prion and
dory because of the instability of Buffers lines.
Author: Fujii Masao
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/20200403025751.GB1759@paquier.xyz
When BUFFERS option is enabled, EXPLAIN command includes the information
on buffer usage during each plan node, in its output. In addition to that,
this commit makes EXPLAIN command include also the information on
buffer usage during planning phase, in its output. This feature makes it
easier to discern the cases where lots of buffer access happen during
planning.
Author: Julien Rouhaud, slightly revised by Fujii Masao
Reviewed-by: Justin Pryzby
Discussion: https://postgr.es/m/16109-26a1a88651e90608@postgresql.org
Instead of disabling autovacuum on these test tables, adjust the
partition boundaries so that the child partitions are not all the
same size. That should cause the planner to use a predictable
ordering of the per-partition scan nodes even in cases where
autovacuum causes the rowcount estimates to be off a bit.
Moreover, this also lets these tests show that the planner does
properly order the tables in descending size order, something
that wasn't being proven before.
The pagg_tab1 and pagg_tab2 partitions are still all the same
size, but that should be fine, because those tables are so small
that (1) autovacuum won't fire on them, and (2) even if it did,
it couldn't change the reltuples value --- with only one page,
it can't see just part of the relation.
Discussion: https://postgr.es/m/24467.1585838693@sss.pgh.pa.us
In b07642dbc, we added code to trigger autovacuums based on the number of
INSERTs into a table. This seems to have cause some destabilization of
the regression tests. Likely this is due to an autovacuum triggering
mid-test and (per theory from Tom Lane) one of the test's queries causes
autovacuum to skip some number of pages, resulting in the reltuples
estimate changing.
The failure that this is attempting to fix is around the order of subnodes
in an Append. Since the planner orders these according to the subnode
cost, then it's possible that a small change in the reltuples value changes
the subnode's cost enough that it swaps position with one of its fellow
subnodes.
The failure here only seems to occur on slower buildfarm machines. In this
case, lousyjack, which seems have taken over 8 minutes to run just
the partitionwise_aggregate test. Such a slow run would increase the
chances that the autovacuum launcher would trigger a vacuum mid-test.
Faster machines run this test in sub second time, so have a much smaller
window for an autovacuum to trigger.
Here we fix this by disabling autovacuum on all tables created in the test.
Additionally, this reverts the change made in the
partitionwise_aggregate test in 2dc16efed.
Discussion: https://postgr.es/m/22297.1585797192@sss.pgh.pa.us
This adds SQL expressions NORMALIZE() and IS NORMALIZED to convert and
check Unicode normal forms, per SQL standard.
To support fast IS NORMALIZED tests, we pull in a new data file
DerivedNormalizationProps.txt from Unicode and build a lookup table
from that, using techniques similar to ones already used for other
Unicode data. make update-unicode will keep it up to date. We only
build and use these tables for the NFC and NFKC forms, because they
are too big for NFD and NFKD and the improvement is not significant
enough there.
Reviewed-by: Daniel Verite <daniel@manitou-mail.org>
Reviewed-by: Andreas Karlsson <andreas@proxel.se>
Discussion: https://www.postgresql.org/message-id/flat/c1909f27-c269-2ed9-12f8-3ab72c8caf7a@2ndquadrant.com
There's a number of SLRU caches used to access important data like clog,
commit timestamps, multixact, asynchronous notifications, etc. Until now
we had no easy way to monitor these shared caches, compute hit ratios,
number of reads/writes etc.
This commit extends the statistics collector to track this information
for a predefined list of SLRUs, and also introduces a new system view
pg_stat_slru displaying the data.
The list of built-in SLRUs is fixed, but additional SLRUs may be defined
in extensions. Unfortunately, there's no suitable registry of SLRUs, so
this patch simply defines a fixed list of SLRUs with entries for the
built-in ones and one entry for all additional SLRUs. Extensions adding
their own SLRU are fairly rare, so this seems acceptable.
This patch only allows monitoring of SLRUs, not tuning. The SLRU sizes
are still fixed (hard-coded in the code) and it's not entirely clear
which of the SLRUs might need a GUC to tune size. In a way, allowing us
to determine that is one of the goals of this patch.
Bump catversion as the patch introduces new functions and system view.
Author: Tomas Vondra
Reviewed-by: Alvaro Herrera
Discussion: https://www.postgresql.org/message-id/flat/20200119143707.gyinppnigokesjok@development
The stats_ext test is not expecting that autovacuum will touch
any of its tables; an expectation falsified by commit b07642dbc.
Although I'm suspicious that there's something else going on that
makes extended stats estimates not 100% reproducible, it's pretty
easy to demonstrate that there are places in this test that fail
if an autovacuum updates the table's stats unexpectedly.
Hence, revert the band-aid changes made by 2dc16efed and 24566b359
in favor of summarily disabling autovacuum for all the tables that
this test checks estimated rowcounts for.
Also remove an evidently obsolete comment at the head of the test.
Discussion: https://postgr.es/m/15012.1585623298@sss.pgh.pa.us
This commit improves error reporting introduced by 911e702077. It puts
argument of errmsg() to the single line for easier grepping source for error
text. Also it improves wording of errhint().
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
PostgreSQL provides set of template index access methods, where opclasses have
much freedom in the semantics of indexing. These index AMs are GiST, GIN,
SP-GiST and BRIN. There opclasses define representation of keys, operations on
them and supported search strategies. So, it's natural that opclasses may be
faced some tradeoffs, which require user-side decision. This commit implements
opclass parameters allowing users to set some values, which tell opclass how to
index the particular dataset.
This commit doesn't introduce new storage in system catalog. Instead it uses
pg_attribute.attoptions, which is used for table column storage options but
unused for index attributes.
In order to evade changing signature of each opclass support function, we
implement unified way to pass options to opclass support functions. Options
are set to fn_expr as the constant bytea expression. It's possible due to the
fact that opclass support functions are executed outside of expressions, so
fn_expr is unused for them.
This commit comes with some examples of opclass options usage. We parametrize
signature length in GiST. That applies to multiple opclasses: tsvector_ops,
gist__intbig_ops, gist_ltree_ops, gist__ltree_ops, gist_trgm_ops and
gist_hstore_ops. Also we parametrize maximum number of integer ranges for
gist__int_ops. However, the main future usage of this feature is expected
to be json, where users would be able to specify which way to index particular
json parts.
Catversion is bumped.
Discussion: https://postgr.es/m/d22c3a18-31c7-1879-fc11-4c1ce2f5e5af%40postgrespro.ru
Author: Nikita Glukhov, revised by me
Reviwed-by: Nikolay Shaplov, Robert Haas, Tom Lane, Tomas Vondra, Alvaro Herrera
Following up on 2dc16efed, petalura has suffered some additional
failures in stats_ext which again appear to be around the timing of an
autovacuum during the test, causing instability in the row estimates.
Again, let's fix this by explicitly performing a VACUUM on the table
and not leave it to happen by chance of an autovacuum pass.
Discussion: https://postgr.es/m/CAApHDvok5hmXr%2BbUbJe7%2B2sQzWo4B_QzSk7RKFR9fP6BjYXx5g%40mail.gmail.com
b07642dbc added code to trigger autovacuums based on the number of
inserts into a table. This seems to have caused some regression test
results to destabilize. I suspect this is due to autovacuum triggering a
vacuum sometime after the test's ANALYZE run and perhaps reltuples is
ending up being set to a slightly different value as a result.
Attempt to resolve this by running a VACUUM ANALYZE on the affected table
instead of just ANALYZE. pg_class.reltuples will still get set to whatever
ANALYZE chooses but we should no longer get the proceeding autovacuum
overriding that.
The overhead this adds to each test's runtime seems small enough not to
worry about. I measure 3-4% on stats_ext and can't measure any change in
partition_aggregate.
I'm unable to recreate the issue locally, so this is a bit of a blind
fix.
Discussion: https://postgr.es/m/CAApHDvpWmpqYrKwwDQyeDq8dAyK7GMNaxDhrG69CkSuXoEg%2BVg%40mail.gmail.com
Instead of using Newton's method to compute numeric square roots, use
the Karatsuba square root algorithm, which performs better for numbers
of all sizes. In practice, this is 3-5 times faster for inputs with
just a few digits and up to around 10 times faster for larger inputs.
Also, the new algorithm guarantees that the final digit of the result
is correctly rounded, since it computes an integer square root with
truncation, containing at least 1 extra decimal digit before rounding.
The former algorithm would occasionally round the wrong way because
it rounded both the intermediate and final results.
In addition, arrange for sqrt_var() to explicitly support negative
rscale values (rounding before the decimal point). This allows the
argument reduction phase of ln_var() to be optimised for large inputs,
since it only needs to compute square roots with a few more digits
than the final ln() result, rather than computing all the digits
before the decimal point. For very large inputs, this can be many
thousands of times faster.
In passing, optimise div_var_fast() in a couple of places where it was
doing unnecessary work.
Patch be me, reviewed by Tom Lane and Tels.
Discussion: https://postgr.es/m/CAEZATCV1A7+jD3P30Zu31KjaxeSEyOn3v9d6tYegpxcq3cQu-g@mail.gmail.com
Formerly we applied a functional dependency "a => b with dependency
degree f" using the formula
P(a,b) = P(a) * [f + (1-f)*P(b)]
This leads to the possibility that the combined selectivity P(a,b)
could exceed P(b), which is not ideal. The addition of support for IN
and OR clauses (commits 8f321bd16c and ccaa3569f5) would seem to make
this more likely, since the user-supplied values in such clauses are
not necessarily compatible with the functional dependency.
Mitigate this by using the formula
P(a,b) = f * Min(P(a), P(b)) + (1-f) * P(a) * P(b)
instead, which guarantees that the combined selectivity is less than
each column's individual selectivity. Logically, this is modifies the
part of the formula that accounts for dependent rows to handle cases
where P(a) > P(b), whilst not changing the second term which accounts
for independent rows.
Additionally, this refactors the way that functional dependencies are
applied, so now dependencies_clauselist_selectivity() estimates both
the implying clauses and the implied clauses for each functional
dependency (formerly only the implied clauses were estimated), and now
all clauses for each attribute are taken into account (formerly only
one clause for each implied attribute was estimated). This removes the
previously built-in assumption that only equality clauses will be
seen, which is no longer true, and opens up the possibility of
applying functional dependencies to more general clauses.
Patch by me, reviewed by Tomas Vondra.
Discussion: https://postgr.es/m/CAEZATCXaNFZyOhR4XXAfkvj1tibRBEjje6ZbXwqWUB_tqbH%3Drw%40mail.gmail.com
Discussion: https://postgr.es/m/20200318002946.6dvblukm3cfmgir2%40development
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
Previously 0 was reported in pg_stat_progress_basebackup.total_backup
if the total backup size was not estimated. Per discussion, our consensus
is that NULL is better choise as the value in total_backup in that case.
So this commit makes pg_stat_progress_basebackup view report NULL
in total_backup column if the estimation is disabled.
Bump catversion.
Author: Fujii Masao
Reviewed-by: Amit Langote, Magnus Hagander, Alvaro Herrera
Discussion: https://postgr.es/m/CABUevExnhOD89zBDuPvfAAh243RzNpwCPEWNLtMYpKHMB8gbAQ@mail.gmail.com
Until now, only selected bulk operations (e.g. COPY) did this. If a
given relfilenode received both a WAL-skipping COPY and a WAL-logged
operation (e.g. INSERT), recovery could lose tuples from the COPY. See
src/backend/access/transam/README section "Skipping WAL for New
RelFileNode" for the new coding rules. Maintainers of table access
methods should examine that section.
To maintain data durability, just before commit, we choose between an
fsync of the relfilenode and copying its contents to WAL. A new GUC,
wal_skip_threshold, guides that choice. If this change slows a workload
that creates small, permanent relfilenodes under wal_level=minimal, try
adjusting wal_skip_threshold. Users setting a timeout on COMMIT may
need to adjust that timeout, and log_min_duration_statement analysis
will reflect time consumption moving to COMMIT from commands like COPY.
Internally, this requires a reliable determination of whether
RollbackAndReleaseCurrentSubTransaction() would unlink a relation's
current relfilenode. Introduce rd_firstRelfilenodeSubid. Amend the
specification of rd_createSubid such that the field is zero when a new
rel has an old rd_node. Make relcache.c retain entries for certain
dropped relations until end of transaction.
Back-patch to 9.5 (all supported versions). This introduces a new WAL
record type, XLOG_GIST_ASSIGN_LSN, without bumping XLOG_PAGE_MAGIC. As
always, update standby systems before master systems. This changes
sizeof(RelationData) and sizeof(IndexStmt), breaking binary
compatibility for affected extensions. (The most recent commit to
affect the same class of extensions was
089e4d405d0f3b94c74a2c6a54357a84a681754b.)
Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert
Haas. Heikki Linnakangas and Michael Paquier implemented earlier
designs that materially clarified the problem. Reviewed, in earlier
designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane,
Fujii Masao, and Simon Riggs. Reported by Martijn van Oosterhout.
Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
This patch adds the pseudo-types anycompatible, anycompatiblearray,
anycompatiblenonarray, and anycompatiblerange. They work much like
anyelement, anyarray, anynonarray, and anyrange respectively, except
that the actual input values need not match precisely in type.
Instead, if we can find a common supertype (using the same rules
as for UNION/CASE type resolution), then the parser automatically
promotes the input values to that type. For example,
"myfunc(anycompatible, anycompatible)" can match a call with one
integer and one bigint argument, with the integer automatically
promoted to bigint. With anyelement in the definition, the user
would have had to cast the integer explicitly.
The new types also provide a second, independent set of type variables
for function matching; thus with "myfunc(anyelement, anyelement,
anycompatible) returns anycompatible" the first two arguments are
constrained to be the same type, but the third can be some other
type, and the result has the type of the third argument. The need
for more than one set of type variables was foreseen back when we
first invented the polymorphic types, but we never did anything
about it.
Pavel Stehule, revised a bit by me
Discussion: https://postgr.es/m/CAFj8pRDna7VqNi8gR+Tt2Ktmz0cq5G93guc3Sbn_NVPLdXAkqA@mail.gmail.com
While performing hash aggregation, track memory usage when adding new
groups to a hash table. If the memory usage exceeds work_mem, enter
"spill mode".
In spill mode, new groups are not created in the hash table(s), but
existing groups continue to be advanced if input tuples match. Tuples
that would cause a new group to be created are instead spilled to a
logical tape to be processed later.
The tuples are spilled in a partitioned fashion. When all tuples from
the outer plan are processed (either by advancing the group or
spilling the tuple), finalize and emit the groups from the hash
table. Then, create new batches of work from the spilled partitions,
and select one of the saved batches and process it (possibly spilling
recursively).
Author: Jeff Davis
Reviewed-by: Tomas Vondra, Adam Lee, Justin Pryzby, Taylor Vesely, Melanie Plageman
Discussion: https://postgr.es/m/507ac540ec7c20136364b5272acbcd4574aa76ef.camel@j-davis.com
Since commit 8f321bd16c functional dependencies can handle IN clauses,
which however introduced a possible (and surprising) inconsistency,
because IN clauses may be expressed as an OR clause, which are still
considered incompatible. For example
a IN (1, 2, 3)
may be rewritten as
(a = 1 OR a = 2 OR a = 3)
The IN clause will work fine with functional dependencies, but the OR
clause will force the estimation to fall back to plain per-column
estimates, possibly introducing significant estimation errors.
This commit recognizes OR clauses equivalent to an IN clause (when all
arugments are compatible and reference the same attribute) as a special
case, compatible with functional dependencies. This allows applying
functional dependencies, just like for IN clauses.
This does not eliminate the difference in estimating the clause itself,
i.e. IN clause and OR clause still use different formulas. It would be
possible to change that (for these special OR clauses), but that's not
really about extended statistics - it was always like this. Moreover the
errors are usually much smaller compared to ignoring dependencies.
Author: Tomas Vondra
Reviewed-by: Dean Rasheed
Discussion: https://www.postgresql.org/message-id/flat/13902317.Eha0YfKkKy%40pierred-pdoc
pg_proc.c and pg_aggregate.c had near-duplicate copies of the logic
to decide whether a function or aggregate's signature is legal.
This seems like a bad thing even without the problem that the
upcoming "anycompatible" patch would roughly double the complexity
of that logic. Hence, refactor so that the rules are localized
in new subroutines supplied by parse_coerce.c. (One could quibble
about just where to add that code, but putting it beside
enforce_generic_type_consistency seems not totally unreasonable.)
The fact that the rules are about to change would mandate some
changes in the wording of the associated error messages in any case.
I ended up spelling things out in a fairly literal fashion in the
errdetail messages, eg "A result of type anyelement requires at
least one input of type anyelement, anyarray, anynonarray, anyenum,
or anyrange." Perhaps this is overkill, but once there's more than
one subgroup of polymorphic types, people might get confused by
more-abstract messages.
Discussion: https://postgr.es/m/24137.1584139352@sss.pgh.pa.us
Ordinarily it's impossible for an actual input of a function to have
declared type ANYARRAY, since we'd resolve that to a concrete array
type before doing argument type resolution for the function. But an
exception arises for functions applied to certain columns of pg_statistic
or pg_stats, since we abuse the "anyarray" pseudotype by using it to
declare those columns. So parse_coerce.c has to deal with the case.
Previously we allowed an ANYARRAY actual input to match an ANYARRAY
polymorphic argument, but only if no other argument or result was
declared ANYELEMENT. When that logic was written, those were the only
two polymorphic types, and I fear nobody thought carefully about how it
ought to extend to the other ones that came along later. But actually
it was wrong even then, because if a function has two ANYARRAY
arguments, it should be able to expect that they have identical element
types, and we'd not be able to ensure that.
The correct generalization is that we can match an ANYARRAY actual input
to an ANYARRAY polymorphic argument only if no other argument or result
is of any polymorphic type, so that no promises are being made about
element type compatibility. check_generic_type_consistency can't test
that condition, but it seems better anyway to accept such matches there
and then throw an error if needed in enforce_generic_type_consistency.
That way we can produce a specific error message rather than an
unintuitive "function does not exist" complaint. (There's some risk
perhaps of getting new ambiguous-function complaints, but I think that
any set of functions for which that could happen would be ambiguous
against ordinary array columns as well.) While we're at it, we can
improve the message that's produced in cases that the code did already
object to, as shown in the regression test changes.
Also, remove a similar test that got cargo-culted in for ANYRANGE;
there are no catalog columns of type ANYRANGE, and I hope we never
create any, so that's not needed. (It was incomplete anyway.)
While here, update some comments and rearrange the code a bit in
preparation for upcoming additions of more polymorphic types.
In practical situations I believe this is just exchanging one error
message for another, hopefully better, one. So it doesn't seem
needful to back-patch, even though the mistake is ancient.
Discussion: https://postgr.es/m/21569.1584314271@sss.pgh.pa.us
It is possible to reach check_sql_fn_retval() with an unresolved
polymorphic rettype, resulting in an assertion failure as demonstrated
by one of the added test cases. However, the code following that
throws what seems an acceptable error message, so just remove the
Assert and adjust commentary.
While here, I thought it'd be a good idea to provide some parallel
tests of SQL-function and PL/pgSQL-function polymorphism behavior.
Some of these cases are perhaps duplicative of tests elsewhere,
but we hadn't any organized coverage of the topic AFAICS.
Although that assertion's been wrong all along, it won't have any
effect in production builds, so I'm not bothering to back-patch.
Discussion: https://postgr.es/m/21569.1584314271@sss.pgh.pa.us
This extends the fixes made in commit 085b6b667 to other SRFs with the
same bug, namely pg_logdir_ls(), pgrowlocks(), pg_timezone_names(),
pg_ls_dir(), and pg_tablespace_databases().
Also adjust various comments and documentation to warn against
expecting to clean up resources during a ValuePerCall SRF's final
call.
Back-patch to all supported branches, since these functions were
all born broken.
Justin Pryzby, with cosmetic tweaks by me
Discussion: https://postgr.es/m/20200308173103.GC1357@telsasoft.com
The regression tests for extended statistics were not testing a couple
of important cases for the MCV lists:
* IS NOT NULL clauses - We did have queries with IS NULL clauses, but
not the negative case.
* clauses with variable on the right - All the clauses had the Var on
the left, i.e. (Var op Const), so this adds (Const op Var) too.
* columns with fixed-length types passed by reference - All columns
were using either by-value or varlena types, so add a test with
UUID columns too. This matters for (de)serialization.
* NULL-only dimension - When one of the columns contains only NULL
values, we treat it a a special case during (de)serialization.
* arrays containing NULL - When the constant parameter contains NULL
value, we need to handle it correctly during estimation, for all
IN, ANY and ALL clauses.
Discussion: https://www.postgresql.org/message-id/flat/20200113230008.g67iyk4cs3xbnjju@development
Author: Tomas Vondra
The regression tests for functional dependencies were only using clauses
of the form (Var op Const), i.e. with Var on the left side. This adds
a couple of queries with Var on the right, to test other code paths.
It also prints one of the functional dependencies, to test the data type
output function. The functional dependencies are "perfect" with degree
of 1.0 so this should be stable.
Discussion: https://www.postgresql.org/message-id/flat/20200113230008.g67iyk4cs3xbnjju@development
Author: Tomas Vondra
resolve_polymorphic_tupdesc() and resolve_polymorphic_argtypes() failed to
cover the case of having to resolve anyarray given only an anyrange input.
The bug was masked if anyelement was also used (as either input or
output), which probably helps account for our not having noticed.
While looking at this I noticed that resolve_generic_type() would produce
the wrong answer if asked to make that same resolution. ISTM that
resolve_generic_type() is confusingly defined and overly complex, so
rather than fix it, let's just make funcapi.c do the specific lookups
it requires for itself.
With this change, resolve_generic_type() is not used anywhere, so remove
it in HEAD. In the back branches, leave it alone (complete with bug)
just in case any external code is using it.
While we're here, make some other refactoring adjustments in funcapi.c
with an eye to upcoming future expansion of the set of polymorphic types:
* Simplify quick-exit tests by adding an overall have_polymorphic_result
flag. This is about a wash now but will be a win when there are more
flags.
* Reduce duplication of code between resolve_polymorphic_tupdesc() and
resolve_polymorphic_argtypes().
* Don't bother to validate correct matching of anynonarray or anyenum;
the parser should have done that, and even if it didn't, just doing
"return false" here would lead to a very confusing, off-point error
message. (Really, "return false" in these two functions should only
occur if the call_expr isn't supplied or we can't obtain data type
info from it.)
* For the same reason, throw an elog rather than "return false" if
we fail to resolve a polymorphic type.
The bug's been there since we added anyrange, so back-patch to
all supported branches.
Discussion: https://postgr.es/m/6093.1584202130@sss.pgh.pa.us
Commit 8f321bd16c added support for estimating ScalarArrayOpExpr clauses
(IN/ANY) clauses using functional dependencies. There's no good reason
not to support estimation of these clauses using multi-variate MCV lists
too, so this commits implements that. That makes the behavior consistent
and MCV lists can estimate all variants (ANY/ALL, inequalities, ...).
Author: Tomas Vondra
Review: Dean Rasheed
Discussion: https://www.postgresql.org/message-id/flat/13902317.Eha0YfKkKy%40pierred-pdoc
Until now functional dependencies supported only simple equality clauses
and clauses that can be trivially translated to equalities. This commit
allows estimation of some ScalarArrayOpExpr (IN/ANY) clauses.
For IN clauses we can do this thanks to using operator with equality
semantics, which means an IN clause
WHERE c IN (1, 2, ..., N)
can be translated to
WHERE (c = 1 OR c = 2 OR ... OR c = N)
IN clauses are now considered compatible with functional dependencies,
and rely on the same assumption of consistency of queries with data
(which is an assumption we already used for simple equality clauses).
This applies also to ALL clauses with an equality operator, which can be
considered equivalent to IN clause.
ALL clauses are still considered incompatible, although there's some
discussion about maybe relaxing this in the future.
Author: Pierre Ducroquet
Reviewed-by: Tomas Vondra, Dean Rasheed
Discussion: https://www.postgresql.org/message-id/flat/13902317.Eha0YfKkKy%40pierred-pdoc
If an index was explicitly set as replica identity index, this setting
was lost when a table was rewritten by ALTER TABLE. Because this
setting is part of pg_index but actually controlled by ALTER
TABLE (not part of CREATE INDEX, say), we have to do some extra work
to restore it.
Based-on-patch-by: Quan Zongliang <quanzongliang@gmail.com>
Reviewed-by: Euler Taveira <euler.taveira@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/c70fcab2-4866-0d9f-1d01-e75e189db342@gmail.com
I forgot that the WAL directory might hold other files besides WAL
segments, notably including new segments still being filled.
That means a blind test for the first file's size being 16MB can
fail. Restrict based on file name length to make it more robust.
Per buildfarm.
This coding technique is undesirable because (a) it leaks the FD for
the rest of the transaction if the SRF is not run to completion, and
(b) allocated FDs are a scarce resource, but multiple interleaved
uses of the relevant functions could eat many such FDs.
In v11 and later, a query such as "SELECT pg_ls_waldir() LIMIT 1"
yields a warning about the leaked FD, and the only reason there's
no warning in earlier branches is that fd.c didn't whine about such
leaks before commit 9cb7db3f0. Even disregarding the warning, it
wouldn't be too hard to run a backend out of FDs with careless use
of these SQL functions.
Hence, rewrite the function so that it reads the directory within
a single call, returning the results as a tuplestore rather than
via value-per-call mode.
There are half a dozen other built-in SRFs with similar problems,
but let's fix this one to start with, just to see if the buildfarm
finds anything wrong with the code.
In passing, fix bogus error report for stat() failure: it was
whining about the directory when it should be fingering the
individual file. Doubtless a copy-and-paste error.
Back-patch to v10 where this function was added.
Justin Pryzby, with cosmetic tweaks and test cases by me
Discussion: https://postgr.es/m/20200308173103.GC1357@telsasoft.com
Since the documentation about LIKE doesn't say that a copied constraint
has properties different from the original, it seems that ignoring
a NO INHERIT property doesn't meet the principle of least surprise.
So make it copy that.
(Note, however, that we still don't copy a NOT VALID property;
CREATE TABLE offers no way to do that, plus it seems pointless.)
Arguably this is a bug fix; but no back-patch, as it seems barely
possible somebody is depending on the current behavior.
Ildar Musin and Chris Travers; reviewed by Amit Langote and myself
Discussion: https://postgr.es/m/CAONYFtMC6C+3AWCVp7Yd8H87Zn0GxG1_iQG6_bQKbaqYZY0=-g@mail.gmail.com
Previously, this code just smashed all types of DefElem values to
strings, cavalierly reasoning that nobody would care. But in point of
fact, most of the defGetFoo functions do distinguish among different
input syntaxes; for instance defGetBoolean will accept 1 as an integer
but not "1" as a string. This led to CREATE/ALTER TEXT SEARCH
DICTIONARY accepting 0 and 1 as values for boolean dictionary
properties, only to have the dictionary fail at runtime.
We can upgrade this behavior by teaching serialize_deflist that it
does not need to quote T_Integer or T_Float nodes' values on output,
and then teaching deserialize_deflist to restore unquoted integer or
float values as the appropriate node type. This should not break
anything using pg_ts_dict.dictinitoption, since that field is just
defined as being something valid to include in CREATE TEXT SEARCH
DICTIONARY.
deserialize_deflist is also used to parse the options arguments
for the ts_headline family of functions, but so far as I can see
this won't cause any problems there either: the only consumer of
that output is prsd_headline which always uses defGetString.
(Really that's a bad idea, but I won't risk changing it here.)
This is surely a bug fix, but given the lack of field complaints
I don't think it's necessary to back-patch.
Discussion: https://postgr.es/m/CAMkU=1xRcs_BUPzR0+V3WndaCAv0E_m3h6aUEJ8NF-sY1nnHsw@mail.gmail.com
When a partitioned table is added to a publication, changes of all of
its partitions (current or future) are published via that publication.
This change only affects which tables a publication considers as its
members. The receiving side still sees the data coming from the
individual leaf partitions. So existing restrictions that partition
hierarchies can only be replicated one-to-one are not changed by this.
Author: Amit Langote <amitlangote09@gmail.com>
Reviewed-by: Rafia Sabih <rafia.pghackers@gmail.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/CA+HiwqH=Y85vRK3mOdjEkqFK+E=ST=eQiHdpj43L=_eJMOOznQ@mail.gmail.com
This commit provides psql commands for listing operator classes, operator
families and its contents in psql. New commands will be useful for exploring
capabilities of both builtin opclasses/opfamilies as well as
opclasses/opfamilies defined in extensions.
Discussion: https://postgr.es/m/1529675324.14193.5.camel%40postgrespro.ru
Author: Sergey Cherkashin, Nikita Glukhov, Alexander Korotkov
Reviewed-by: Michael Paquier, Alvaro Herrera, Arthur Zakirov
Reviewed-by: Kyotaro Horiguchi, Andres Freund
SQL includes provisions for numeric Unicode escapes in string
literals and identifiers. Previously we only accepted those
if they represented ASCII characters or the server encoding
was UTF-8, making the conversion to internal form trivial.
This patch adjusts things so that we'll call the appropriate
encoding conversion function in less-trivial cases, allowing
the escape sequence to be accepted so long as it corresponds
to some character available in the server encoding.
This also applies to processing of Unicode escapes in JSONB.
However, the old restriction still applies to client-side
JSON processing, since that hasn't got access to the server's
encoding conversion infrastructure.
This patch includes some lexer infrastructure that simplifies
throwing errors with error cursors pointing into the middle of
a string (or other complex token). For the moment I only used
it for errors relating to Unicode escapes, but we might later
expand the usage to some other cases.
Patch by me, reviewed by John Naylor.
Discussion: https://postgr.es/m/2393.1578958316@sss.pgh.pa.us
Specifically, this patch allows ALTER TYPE to:
* Change the default TOAST strategy for a toastable base type;
* Promote a non-toastable type to toastable;
* Add/remove binary I/O functions for a type;
* Add/remove typmod I/O functions for a type;
* Add/remove a custom ANALYZE statistics functions for a type.
The first of these can be done by the type's owner; all the others
require superuser privilege since misuse could cause problems.
The main motivation for this patch is to allow extensions to
upgrade the feature sets of their data types, so the set of
alterable properties is biased towards that use-case. However
it's also true that changing some other properties would be
a lot harder, as they get baked into physical storage and/or
stored expressions that depend on the type.
Along the way, refactor GenerateTypeDependencies() to make it easier
to call, refactor DefineType's volatility checks so they can be shared
by AlterType, and teach typcache.c that it might have to reload data
from the type's pg_type row, a scenario it never handled before.
Also rearrange alter_type.sgml a bit for clarity (put the
composite-type operations together).
Tomas Vondra and Tom Lane
Discussion: https://postgr.es/m/20200228004440.b23ein4qvmxnlpht@development
A long time ago, it was necessary to declare datatype I/O functions,
triggers, and language handler support functions in a very type-unsafe
way involving a single pseudo-type "opaque". We got rid of those
conventions in 7.3, but there was still support in various places to
automatically convert such functions to the modern declaration style,
to be able to transparently re-load dumps from pre-7.3 servers.
It seems unnecessary to continue to support that anymore, so take out
the hacks; whereupon the "opaque" pseudo-type itself is no longer
needed and can be dropped.
This is part of a group of patches removing various server-side kluges
for transparently upgrading pre-8.0 dump files. Since we've had few
complaints about dropping pg_dump's support for dumping from pre-8.0
servers (commit 64f3524e2), it seems okay to now remove these kluges.
Discussion: https://postgr.es/m/4110.1583255415@sss.pgh.pa.us
to_char() has long allowed the TM (translation mode) prefix to
specify output of translated month or day names; but that prefix
had no effect in input format strings. Now it does. to_date()
and to_timestamp() will now recognize the same month or day names
that to_char() would output for the same format code. Matching is
case-insensitive (per the active collation's notion of what that
means), just as it has always been for English month/day names
without the TM prefix.
(As per the discussion thread, there are lots of cases that this
feature will not handle, such as alternate day names. But being
able to accept what to_char() will output seems useful enough.)
In passing, fix some shaky English and violations of message
style guidelines in jsonpath errors for the .datetime() method,
which depends on this code.
Juan José Santamaría Flecha, reviewed and modified by me,
with other commentary from Alvaro Herrera, Tomas Vondra,
Arthur Zakirov, Peter Eisentraut, Mark Dilger.
Discussion: https://postgr.es/m/CAC+AXB3u1jTngJcoC1nAHBf=M3v-jrEfo86UFtCqCjzbWS9QhA@mail.gmail.com
Using ALTER TABLE ATTACH PARTITION causes an assertion failure when
attempting to work on a partitioned index, because partitioned indexes
cannot have partition bounds.
The grammar of ALTER TABLE ATTACH PARTITION requires partition bounds,
but not ALTER INDEX, so mixing ALTER TABLE with partitioned indexes is
confusing. Hence, on HEAD, prevent ALTER TABLE to attach a partition if
the relation involved is a partitioned index. On back-branches, as
applications may rely on the existing behavior, just remove the
culprit assertion.
Reported-by: Alexander Lakhin
Author: Amit Langote, Michael Paquier
Discussion: https://postgr.es/m/16276-5cd1dcc8fb8be7b5@postgresql.org
Backpatch-through: 11
This commit adds pg_stat_progress_basebackup view that reports
the progress while an application like pg_basebackup is taking
a base backup. This uses the progress reporting infrastructure
added by c16dc1aca5, adding support for streaming base backup.
Bump catversion.
Author: Fujii Masao
Reviewed-by: Kyotaro Horiguchi, Amit Langote, Sergei Kornilov
Discussion: https://postgr.es/m/9ed8b801-8215-1f3d-62d7-65bff53f6e94@oss.nttdata.com
If the flag value is lost, a CLUSTER query following REINDEX
CONCURRENTLY could fail. Non-concurrent REINDEX is already handling
this case consistently.
Author: Justin Pryzby
Discussion: https://postgr.es/m/20200229024202.GH29456@telsasoft.com
Backpatch-through: 12
When deciding on the local rscale to use for the Taylor series
expansion, ln_var() neglected to account for the fact that the result
is subsequently multiplied by a factor of 2^(nsqrt+1), where nsqrt is
the number of square root operations performed in the range reduction
step, which can be as high as 22 for very large inputs. This could
result in a loss of precision, particularly when combined with large
rscale values, for which a large number of Taylor series terms is
required (up to around 400).
Fix by computing a few extra digits in the Taylor series, based on the
weight of the multiplicative factor log10(2^(nsqrt+1)). It remains to
be proven whether or not the other 8 extra digits used for the Taylor
series is appropriate, but this at least deals with the obvious
oversight of failing to account for the effects of the final
multiplication.
Per report from Justin AnyhowStep. Reviewed by Tom Lane.
Discussion: https://postgr.es/m/16280-279f299d9c06e56f@postgresql.org
Commit 356687bd8 omitted to remove leftover code for destroying
a hashed subplan's hash tables, with the result that the tables
were always rebuilt not reused; this leads to severe memory
leakage if a hashed subplan is re-executed enough times.
Moreover, the code for reusing the hashnulls table had a typo
that would have made it do the wrong thing if it were reached.
Looking at the code coverage report shows severe under-coverage
of the potential callers of ResetTupleHashTable, so add some test
cases that exercise them.
Andreas Karlsson and Tom Lane, per reports from Ranier Vilela
and Justin Pryzby.
Backpatch to v11, as the faulty commit was.
Discussion: https://postgr.es/m/edb62547-c453-c35b-3ed6-a069e4d6b937@proxel.se
Discussion: https://postgr.es/m/CAEudQAo=DCebm1RXtig9OH+QivpS97sMkikt0A9qHmMUs+g6ZA@mail.gmail.com
Discussion: https://postgr.es/m/20200210032547.GA1412@telsasoft.com
eval_const_expressions sometimes produced RelabelType nodes that
were useless because they just relabeled an expression to the same
exposed type it already had. This is worth avoiding because it can
cause two equivalent expressions to not be equal(), preventing
recognition of useful optimizations. In the test case added here,
an unpatched planner fails to notice that the "sqli = constant" clause
renders a sort step unnecessary, because one code path produces an
extra RelabelType and another doesn't.
Fix by ensuring that eval_const_expressions_mutator's T_RelabelType
case will not add in an unnecessary RelabelType. Also save some
code by sharing a subroutine with the effectively-equivalent cases
for CollateExpr and CoerceToDomain. (CollateExpr had no bug, and
I think that the case couldn't arise with CoerceToDomain, but
it seems prudent to do the same check for all three cases.)
Back-patch to v12. In principle this has been wrong all along,
but I haven't seen a case where it causes visible misbehavior
before v12, so refrain from changing stable branches unnecessarily.
Per investigation of a report from Eric Gillum.
Discussion: https://postgr.es/m/CAMmjdmvAZsUEskHYj=KT9sTukVVCiCSoe_PBKOXsncFeAUDPCQ@mail.gmail.com
Deduplication reduces the storage overhead of duplicates in indexes that
use the standard nbtree index access method. The deduplication process
is applied lazily, after the point where opportunistic deletion of
LP_DEAD-marked index tuples occurs. Deduplication is only applied at
the point where a leaf page split would otherwise be required. New
posting list tuples are formed by merging together existing duplicate
tuples. The physical representation of the items on an nbtree leaf page
is made more space efficient by deduplication, but the logical contents
of the page are not changed. Even unique indexes make use of
deduplication as a way of controlling bloat from duplicates whose TIDs
point to different versions of the same logical table row.
The lazy approach taken by nbtree has significant advantages over a GIN
style eager approach. Most individual inserts of index tuples have
exactly the same overhead as before. The extra overhead of
deduplication is amortized across insertions, just like the overhead of
page splits. The key space of indexes works in the same way as it has
since commit dd299df8 (the commit that made heap TID a tiebreaker
column).
Testing has shown that nbtree deduplication can generally make indexes
with about 10 or 15 tuples for each distinct key value about 2.5X - 4X
smaller, even with single column integer indexes (e.g., an index on a
referencing column that accompanies a foreign key). The final size of
single column nbtree indexes comes close to the final size of a similar
contrib/btree_gin index, at least in cases where GIN's posting list
compression isn't very effective. This can significantly improve
transaction throughput, and significantly reduce the cost of vacuuming
indexes.
A new index storage parameter (deduplicate_items) controls the use of
deduplication. The default setting is 'on', so all new B-Tree indexes
automatically use deduplication where possible. This decision will be
reviewed at the end of the Postgres 13 beta period.
There is a regression of approximately 2% of transaction throughput with
synthetic workloads that consist of append-only inserts into a table
with several non-unique indexes, where all indexes have few or no
repeated values. The underlying issue is that cycles are wasted on
unsuccessful attempts at deduplicating items in non-unique indexes.
There doesn't seem to be a way around it short of disabling
deduplication entirely. Note that deduplication of items in unique
indexes is fairly well targeted in general, which avoids the problem
there (we can use a special heuristic to trigger deduplication passes in
unique indexes, since we're specifically targeting "version bloat").
Bump XLOG_PAGE_MAGIC because xl_btree_vacuum changed.
No bump in BTREE_VERSION, since the representation of posting list
tuples works in a way that's backwards compatible with version 4 indexes
(i.e. indexes built on PostgreSQL 12). However, users must still
REINDEX a pg_upgrade'd index to use deduplication, regardless of the
Postgres version they've upgraded from. This is the only way to set the
new nbtree metapage flag indicating that deduplication is generally
safe.
Author: Anastasia Lubennikova, Peter Geoghegan
Reviewed-By: Peter Geoghegan, Heikki Linnakangas
Discussion:
https://postgr.es/m/55E4051B.7020209@postgrespro.ruhttps://postgr.es/m/4ab6e2db-bcee-f4cf-0916-3a06e6ccbb55@postgrespro.ru
Invent the concept of a B-Tree equalimage ("equality implies image
equality") support function, registered as support function 4. This
indicates whether it is safe (or not safe) to apply optimizations that
assume that any two datums considered equal by an operator class's order
method must be interchangeable without any loss of semantic information.
This is static information about an operator class and a collation.
Register an equalimage routine for almost all of the existing B-Tree
opclasses. We only need two trivial routines for all of the opclasses
that are included with the core distribution. There is one routine for
opclasses that index non-collatable types (which returns 'true'
unconditionally), plus another routine for collatable types (which
returns 'true' when the collation is a deterministic collation).
This patch is infrastructure for an upcoming patch that adds B-Tree
deduplication.
Author: Peter Geoghegan, Anastasia Lubennikova
Discussion: https://postgr.es/m/CAH2-Wzn3Ee49Gmxb7V1VJ3-AC8fWn-Fr8pfWQebHe8rYRxt5OQ@mail.gmail.com
Avoid a join between relations having the FK to detect FK violation.
The planner might optimize this considering the PK must exist on the
referenced side at some point, effectively masking a bug this test
tries to detect.
Tom Lane and Jehan-Guillaume de Rorthais
Discussion: https://postgr.es/m/467.1581270529@sss.pgh.pa.us
The function hash table keys made by compute_function_hashkey() failed
to distinguish event-trigger call context from regular call context.
This meant that once we'd successfully made a hash entry for an event
trigger (either by validation, or by normal use as an event trigger),
an attempt to call the trigger function as a plain function would
find this hash entry and thereby bypass the you-can't-do-that check in
do_compile(). Thus we'd attempt to execute the function, leading to
strange errors or even crashes, depending on function contents and
server version.
To fix, add an isEventTrigger field to PLpgSQL_func_hashkey,
paralleling the longstanding infrastructure for regular triggers.
This fits into what had been pad space, so there's no risk of an ABI
break, even assuming that any third-party code is looking at these
hash keys. (I considered replacing isTrigger with a PLpgSQL_trigtype
enum field, but felt that that carried some API/ABI risk. Maybe we
should change it in HEAD though.)
Per bug #16266 from Alexander Lakhin. This has been broken since
event triggers were invented, so back-patch to all supported branches.
Discussion: https://postgr.es/m/16266-fcd7f838e97ba5d4@postgresql.org
Previously, LOCK TABLE command through a parent table checked
the permissions on not only the parent table but also the children
tables inherited from it. This was a bug and inherited queries should
perform access permission checks on the parent table only. This
commit fixes LOCK TABLE so that it does not check the permission
on children tables.
This patch is applied only in the master branch. We decided not to
back-patch because it's not hard to imagine that there are some
applications expecting the old behavior and the change breaks their
security.
Author: Amit Langote
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/CAHGQGwE+GauyG7POtRfRwwthAGwTjPQYdFHR97+LzA4RHGnJxA@mail.gmail.com
On a multi-level partioned table, when adding a partition not directly
connected to the root table, foreign key constraints referencing the
root were not cloned to the new partition, leading to the FK being
possibly inadvertently violated later on.
This was caused by fuzzy thinking in CloneFkReferenced (commit
f56f8f8da6): it was skipping constraints marked as having parents on
the theory that cloning those would create duplicates; but that's only
correct for the top level of the partitioning hierarchy. For levels
below that one, such constraints must still be considered and only
skipped if later on we see that we'd create duplicates. Apparently, I
(Álvaro) wrote the comments right but the code implemented something
slightly different.
Author: Jehan-Guillaume de Rorthais
Discussion: https://postgr.es/m/20200206004948.238352db@firost
When running TRUNCATE CASCADE on a child of a partitioned table
referenced by another partitioned table, the truncate was not applied to
partitions of the referencing table; this could leave rows violating the
constraint in the referencing partitioned table. Repair by walking the
pg_constraint chain all the way up to the topmost referencing table.
Note: any partitioned tables containing FKs that reference other
partitioned tables should be checked for possible violating rows, if
TRUNCATE has occurred in partitions of the referenced table.
Reported-by: Christophe Courtois
Author: Jehan-Guillaume de Rorthais
Discussion: https://postgr.es/m/20200204183906.115f693e@firost
Commit 147e3722f7 changed Tid scan so that it calls table_beginscan()
and uses the scan option for seq scan. This change caused two issues.
(1) The change caused Tid scan to take a predicate lock on the entire
relation in serializable transaction even when relation-level
lock is not necessary. This could lead to an unexpected
serialization error.
(2) The change caused Tid scan to increment the number of seq_scan
in pg_stat_*_tables views even though it's not seq scan. This
could confuse the users.
This commit adds the scan option for Tid scan and makes Tid scan
use it, to avoid those issues.
Back-patch to v12, where the bug was introduced.
Author: Tatsuhito Kasahara
Reviewed-by: Kyotaro Horiguchi, Masahiko Sawada, Fujii Masao
Discussion: https://postgr.es/m/CAP0=ZVKy+gTbFmB6X_UW0pP3WaeJ-fkUWHoD-pExS=at3CY76g@mail.gmail.com
This new field tracks the PID of the group leader used with parallel
query. For parallel workers and the leader, the value is set to the
PID of the group leader. So, for the group leader, the value is the
same as its own PID. Note that this reflects what PGPROC stores in
shared memory, so as leader_pid is NULL if a backend has never been
involved in parallel query. If the backend is using parallel query or
has used it at least once, the value is set until the backend exits.
Author: Julien Rouhaud
Reviewed-by: Sergei Kornilov, Guillaume Lelarge, Michael Paquier, Tomas
Vondra
Discussion: https://postgr.es/m/CAOBaU_Yy5bt0vTPZ2_LUM6cUcGeqmYNoJ8-Rgto+c2+w3defYA@mail.gmail.com
Tuple conversion incorrectly concluded that no conversion was needed
as long as all the attributes lined up. But if the source tuple has a
missing attribute (from addition of a column with default), then the
destination tupdesc might not reflect the same default. The typical
symptom was that the affected columns would be unexpectedly NULL.
Repair by always forcing conversion if the source has missing
attributes, which will be filled in by the deform operation. (In
theory we could optimize for when the destination has the same
default, but that seemed overkill.)
Backpatch to 11 where missing attributes were added.
Per bug #16242.
Vik Fearing (discovery, code, testing) and me (analysis, testcase).
Discussion: https://postgr.es/m/16242-d1c9fca28445966b@postgresql.org
Commit 499be013d added this field in a rather poorly-thought-through
manner, with the result being that rather than being a field of the
Append or MergeAppend plan node as intended (and as it seems to be,
in text format), it was actually an element of the "Plans" subgroup.
At least in JSON format, that's flat out invalid syntax, because
"Plans" is an array not an object.
While it's not hard to move the generation of the field so that it
appears where it's supposed to, this does result in a visible change
in field order in text format, in cases where a Append or MergeAppend
plan node has any InitPlans attached. That's slightly annoying to
do in stable branches; but the alternative of continuing to emit
broken non-text formats seems worse.
Also, since the set of fields emitted is not supposed to be
data-dependent in non-text formats, make sure that "Subplans Removed"
appears in Append and MergeAppend nodes even when it's zero, in those
formats. (The previous coding made it look like it could appear in
some other node types such as BitmapAnd, but we don't actually support
runtime pruning there, so don't emit it in those cases.)
Per bug #16171 from Mahadevan Ramachandran. Fix by Daniel Gustafsson
and Tom Lane, reviewed by Hamid Akhtar. Back-patch to v11 where this
code came in.
Discussion: https://postgr.es/m/16171-b72259ab75505fa2@postgresql.org
Commit fc7695891 changed CheckAttributeType to recurse into ranges,
but made it pass down the wrong collation (always InvalidOid, since
ranges as such have no collation). This would result in guaranteed
failure when considering a range type whose subtype is collatable.
Embarrassingly, we lack any regression tests that would expose such
a problem (but fortunately, somebody noticed before we shipped this
bug in any release).
Fix it to pass down the range's subtype collation property instead,
and add some regression test cases to exercise collatable-subtype
ranges a bit more. Back-patch to all supported branches, as the
previous patch was.
Report and patch by Julien Rouhaud, test cases tweaked by me
Discussion: https://postgr.es/m/CAOBaU_aBWqNweiGUFX0guzBKkcfJ8mnnyyGC_KBQmO12Mj5f_A@mail.gmail.com
Previously, TRUNCATE command through a parent table checked the
permissions on not only the parent table but also the children tables
inherited from it. This was a bug and inherited queries should perform
access permission checks on the parent table only. This commit fixes
that bug.
Back-patch to all supported branches.
Author: Amit Langote
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/CAHGQGwFHdSvifhJE+-GSNqUHSfbiKxaeQQ7HGcYz6SC2n_oDcg@mail.gmail.com
This patch creates a new extension property, "trusted". An extension
that's marked that way in its control file can be installed by a
non-superuser who has the CREATE privilege on the current database,
even if the extension contains objects that normally would have to be
created by a superuser. The objects within the extension will (by
default) be owned by the bootstrap superuser, but the extension itself
will be owned by the calling user. This allows replicating the old
behavior around trusted procedural languages, without all the
special-case logic in CREATE LANGUAGE. We have, however, chosen to
loosen the rules slightly: formerly, only a database owner could take
advantage of the special case that allowed installation of a trusted
language, but now anyone who has CREATE privilege can do so.
Having done that, we can delete the pg_pltemplate catalog, moving the
knowledge it contained into the extension script files for the various
PLs. This ends up being no change at all for the in-core PLs, but it is
a large step forward for external PLs: they can now have the same ease
of installation as core PLs do. The old "trusted PL" behavior was only
available to PLs that had entries in pg_pltemplate, but now any
extension can be marked trusted if appropriate.
This also removes one of the stumbling blocks for our Python 2 -> 3
migration, since the association of "plpythonu" with Python 2 is no
longer hard-wired into pg_pltemplate's initial contents. Exactly where
we go from here on that front remains to be settled, but one problem
is fixed.
Patch by me, reviewed by Peter Eisentraut, Stephen Frost, and others.
Discussion: https://postgr.es/m/5889.1566415762@sss.pgh.pa.us
This gives more information to the user about the error and it makes such
messages consistent with the other similar messages in the code.
Reported-by: Simon Riggs
Author: Mahendra Singh and Simon Riggs
Reviewed-by: Beena Emerson and Amit Kapila
Discussion: https://postgr.es/m/CANP8+j+7YUvQvGxTrCiw77R23enMJ7DFmyA3buR+fa2pKs4XhA@mail.gmail.com
In non-TEXT output formats, the "Settings" field should appear when
requested, even if it would be empty.
Also, get rid of the premature optimization of counting all the
GUC_EXPLAIN variables at startup. Since there was no provision for
adjusting that count later, all it'd take would be some extension marking
a parameter as GUC_EXPLAIN to risk an assertion failure or memory stomp.
We could make get_explain_guc_options() count those variables on-the-fly,
or dynamically resize its array ... but TBH I do not think that making a
transient array of pointers a bit smaller is worth any extra complication,
especially when you consider all the other transient space EXPLAIN eats.
So just allocate that array at the max possible size.
In HEAD, also add some regression test coverage for this feature.
Because of the memory-stomp hazard, back-patch to v12 where this
feature was added.
Discussion: https://postgr.es/m/19416.1580069629@sss.pgh.pa.us
Previously, it was possible for EXPLAIN ANALYZE of a parallel query
to produce several different "Workers" fields for a single plan node,
because different portions of explain.c independently generated
per-worker data and wrapped that output in separate fields. This
is pretty bogus, especially for the structured output formats: even
if it's not technically illegal, most programs would have a hard time
dealing with such data.
To improve matters, add infrastructure that allows redirecting
per-worker values into a side data structure, and then collect that
data into a single "Workers" field after we've finished running all
the relevant code for a given plan node.
There are a few visible side-effects:
* In text format, instead of something like
Sort Method: external merge Disk: 4920kB
Worker 0: Sort Method: external merge Disk: 5880kB
Worker 1: Sort Method: external merge Disk: 5920kB
Buffers: shared hit=682 read=10188, temp read=1415 written=2101
Worker 0: actual time=130.058..130.324 rows=1324 loops=1
Buffers: shared hit=337 read=3489, temp read=505 written=739
Worker 1: actual time=130.273..130.512 rows=1297 loops=1
Buffers: shared hit=345 read=3507, temp read=505 written=744
you get
Sort Method: external merge Disk: 4920kB
Buffers: shared hit=682 read=10188, temp read=1415 written=2101
Worker 0: actual time=130.058..130.324 rows=1324 loops=1
Sort Method: external merge Disk: 5880kB
Buffers: shared hit=337 read=3489, temp read=505 written=739
Worker 1: actual time=130.273..130.512 rows=1297 loops=1
Sort Method: external merge Disk: 5920kB
Buffers: shared hit=345 read=3507, temp read=505 written=744
* When JIT is enabled, any relevant per-worker JIT stats are attached
to the child node of the Gather or Gather Merge node, which is where
the other per-worker output has always been. Previously, that info
was attached directly to a Gather node, or missed entirely for Gather
Merge.
* A query's summary JIT data no longer includes a bogus
"Worker Number: -1" field.
A notable code-level change is that indenting for lines of text-format
output should now be handled by calling "ExplainIndentText(es)",
instead of hard-wiring how much space to emit. This seems a good deal
cleaner anyway.
This patch also adds a new "explain.sql" regression test script that's
dedicated to testing EXPLAIN. There is more that can be done in that
line, certainly, but for now it just adds some coverage of the XML and
YAML output formats, which had been completely untested.
Although this is surely a bug fix, it's not clear that people would
be happy with rearranging EXPLAIN output in a minor release, so apply
to HEAD only.
Maciek Sakrejda and Tom Lane, based on an idea of Andres Freund's;
reviewed by Georgios Kokolatos
Discussion: https://postgr.es/m/CAOtHd0AvAA8CLB9Xz0wnxu1U=zJCKrr1r4QwwXi_kcQsHDVU=Q@mail.gmail.com
I had supposed that the from_char_seq_search() call sites were
all passing the constant arrays you'd expect them to pass ...
but on looking closer, the one for DY format was passing the
days[] array not days_short[]. This accidentally worked because
the day abbreviations in English are all the same as the first
three letters of the full day names. However, once we took out
the "maximum comparison length" logic, it stopped working.
As penance for that oversight, add regression test cases covering
this, as well as every other switch case in DCH_from_char() that
was not reached according to the code coverage report.
Also, fold the DCH_RM and DCH_rm cases into one --- now that
seq_search is case independent, there's no need to pass different
comparison arrays for those cases.
Back-patch, as the previous commit was.
seq_search(), which is used to match input substrings to constants
such as month and day names, had a lot of bizarre and unnecessary
behaviors. It was mostly possible to avert our eyes from that before,
but we don't want to duplicate those behaviors in the upcoming patch
to allow recognition of non-English month and day names. So it's time
to clean this up. In particular:
* seq_search scribbled on the input string, which is a pretty dangerous
thing to do, especially in the badly underdocumented way it was done here.
Fortunately the input string is a temporary copy, but that was being made
three subroutine levels away, making it something easy to break
accidentally. The behavior is externally visible nonetheless, in the form
of odd case-folding in error reports about unrecognized month/day names.
The scribbling is evidently being done to save a few calls to pg_tolower,
but that's such a cheap function (at least for ASCII data) that it's
pretty pointless to worry about. In HEAD I switched it to be
pg_ascii_tolower to ensure it is cheap in all cases; but there are corner
cases in Turkish where this'd change behavior, so leave it as pg_tolower
in the back branches.
* seq_search insisted on knowing the case form (all-upper, all-lower,
or initcap) of the constant strings, so that it didn't have to case-fold
them to perform case-insensitive comparisons. This likewise seems like
excessive micro-optimization, given that pg_tolower is certainly very
cheap for ASCII data. It seems unsafe to assume that we know the case
form that will come out of pg_locale.c for localized month/day names, so
it's better just to define the comparison rule as "downcase all strings
before comparing". (The choice between downcasing and upcasing is
arbitrary so far as English is concerned, but it might not be in other
locales, so follow citext's lead here.)
* seq_search also had a parameter that'd cause it to report a match
after a maximum number of characters, even if the constant string were
longer than that. This was not actually used because no caller passed
a value small enough to cut off a comparison. Replicating that behavior
for localized month/day names seems expensive as well as useless, so
let's get rid of that too.
* from_char_seq_search used the maximum-length parameter to truncate
the input string in error reports about not finding a matching name.
This leads to rather confusing reports in many cases. Worse, it is
outright dangerous if the input string isn't all-ASCII, because we
risk truncating the string in the middle of a multibyte character.
That'd lead either to delivering an illegible error message to the
client, or to encoding-conversion failures that obscure the actual
data problem. Get rid of that in favor of truncating at whitespace
if any (a suggestion due to Alvaro Herrera).
In addition to fixing these things, I const-ified the input string
pointers of DCH_from_char and its subroutines, to make sure there
aren't any other scribbling-on-input problems.
The risk of generating a badly-encoded error message seems like
enough of a bug to justify back-patching, so patch all supported
branches.
Discussion: https://postgr.es/m/29432.1579731087@sss.pgh.pa.us
This test case was sketched in commit message 4c87010981 to explain an
ancient bug; it translates to a coverage increase, so add it to the BRIN
regression tests.
Attempting to use CREATE INDEX, DROP INDEX or REINDEX with CONCURRENTLY
on a temporary relation with ON COMMIT actions triggered unexpected
errors because those operations use multiple transactions internally to
complete their work. Here is for example one confusing error when using
ON COMMIT DELETE ROWS:
ERROR: index "foo" already contains data
Issues related to temporary relations and concurrent indexing are fixed
in this commit by enforcing the non-concurrent path to be taken for
temporary relations even if using CONCURRENTLY, transparently to the
user. Using a non-concurrent path does not matter in practice as locks
cannot be taken on a temporary relation by a session different than the
one owning the relation, and the non-concurrent operation is more
effective.
The problem exists with REINDEX since v12 with the introduction of
CONCURRENTLY, and with CREATE/DROP INDEX since CONCURRENTLY exists for
those commands. In all supported versions, this caused only confusing
error messages to be generated. Note that with REINDEX, it was also
possible to issue a REINDEX CONCURRENTLY for a temporary relation owned
by a different session, leading to a server crash.
The idea to enforce transparently the non-concurrent code path for
temporary relations comes originally from Andres Freund.
Reported-by: Manuel Rigger
Author: Michael Paquier, Heikki Linnakangas
Reviewed-by: Andres Freund, Álvaro Herrera, Heikki Linnakangas
Discussion: https://postgr.es/m/CA+u7OA6gP7YAeCguyseusYcc=uR8+ypjCcgDDCTzjQ+k6S9ksQ@mail.gmail.com
Backpatch-through: 9.4
The behavior of something like
ALTER TABLE transactions
ADD COLUMN status varchar(30) DEFAULT 'old',
ALTER COLUMN status SET default 'current';
is to fill existing table rows with 'old', not 'current'. That's
intentional and desirable for a couple of reasons:
* It makes the behavior the same whether you merge the sub-commands
into one ALTER command or give them separately;
* If we applied the new default while filling the table, there would
be no way to get the existing behavior in one SQL command.
The same reasoning applies in cases that add a column and then
manipulate its GENERATED/IDENTITY status in a second sub-command,
since the generation expression is really just a kind of default.
However, that wasn't very obvious (at least not to me; earlier in
the referenced discussion thread I'd thought it was a bug to be
fixed). And it certainly wasn't documented.
Hence, add documentation, code comments, and a test case to clarify
that this behavior is all intentional.
In passing, adjust ATExecAddColumn's defaults-related relkind check
so that it matches up exactly with ATRewriteTables, instead of being
effectively (though not literally) the negated inverse condition.
The reasoning can be explained a lot more concisely that way, too
(not to mention that the comment now matches the code, which it
did not before).
Discussion: https://postgr.es/m/10365.1558909428@sss.pgh.pa.us
Some buildfarm members were still warning about this, because in
9c679a08f I'd missed decorating one of the ereport() code paths
with a dummy return.
Also, adjust the error messages to be more in line with project
style guide.
This feature allows the vacuum to leverage multiple CPUs in order to
process indexes. This enables us to perform index vacuuming and index
cleanup with background workers. This adds a PARALLEL option to VACUUM
command where the user can specify the number of workers that can be used
to perform the command which is limited by the number of indexes on a
table. Specifying zero as a number of workers will disable parallelism.
This option can't be used with the FULL option.
Each index is processed by at most one vacuum process. Therefore parallel
vacuum can be used when the table has at least two indexes.
The parallel degree is either specified by the user or determined based on
the number of indexes that the table has, and further limited by
max_parallel_maintenance_workers. The index can participate in parallel
vacuum iff it's size is greater than min_parallel_index_scan_size.
Author: Masahiko Sawada and Amit Kapila
Reviewed-by: Dilip Kumar, Amit Kapila, Robert Haas, Tomas Vondra,
Mahendra Singh and Sergei Kornilov
Tested-by: Mahendra Singh and Prabhat Sahu
Discussion:
https://postgr.es/m/CAD21AoDTPMgzSkV4E3SFo1CH_x50bf5PqZFQf4jmqjk-C03BWg@mail.gmail.comhttps://postgr.es/m/CAA4eK1J-VoR9gzS5E75pcD-OH0mEyCdp8RihcwKrcuw7J-Q0+w@mail.gmail.com
The strategy of GIN index scan is driven by opclass-specific extract_query
method. This method that needed search mode is GIN_SEARCH_MODE_ALL. This
mode means that matching tuple may contain none of extracted entries. Simple
example is '!term' tsquery, which doesn't need any term to exist in matching
tsvector.
In order to handle such scan key GIN calculates virtual entry, which contains
all TIDs of all entries of attribute. In fact this is full scan of index
attribute. And typically this is very slow, but allows to handle some queries
correctly in GIN. However, current algorithm calculate such virtual entry for
each GIN_SEARCH_MODE_ALL scan key even if they are multiple for the same
attribute. This is clearly not optimal.
This commit improves the situation by introduction of "exclude only" scan keys.
Such scan keys are not capable to return set of matching TIDs. Instead, they
are capable only to filter TIDs produced by normal scan keys. Therefore,
each attribute should contain at least one normal scan key, while rest of them
may be "exclude only" if search mode is GIN_SEARCH_MODE_ALL.
The same optimization might be applied to the whole scan, not per-attribute.
But that leads to NULL values elimination problem. There is trade-off between
multiple possible ways to do this. We probably want to do this later using
some cost-based decision algorithm.
Discussion: https://postgr.es/m/CAOBaU_YGP5-BEt5Cc0%3DzMve92vocPzD%2BXiZgiZs1kjY0cj%3DXBg%40mail.gmail.com
Author: Nikita Glukhov, Alexander Korotkov, Tom Lane, Julien Rouhaud
Reviewed-by: Julien Rouhaud, Tomas Vondra, Tom Lane
Commit 9b63c13f0 turns out to have been fundamentally misguided:
the parent node's subPlan list is by no means the only way in which
a child SubPlan node can be hooked into the outer execution state.
As shown in bug #16213 from Matt Jibson, we can also get short-lived
tuple table slots added to the outer es_tupleTable list. At this point
I have little faith that there aren't other possible connections as
well; the long time it took to notice this problem shows that this
isn't a heavily-exercised situation.
Therefore, revert that fix, returning to the coding that passed a
NULL parent plan pointer down to the transiently-built subexpressions.
That gives us a pretty good guarantee that they won't hook into the
outer executor state in any way. But then we need some other solution
to make SubPlans work. Adopt the solution speculated about in the
previous commit's log message: do expression initialization at plan
startup for just those VALUES rows containing SubPlans, abandoning the
goal of reclaiming memory intra-query for those rows. In practice it
seems unlikely that queries containing a vast number of VALUES rows
would be using SubPlans in them, so this should not give up much.
(BTW, this test case also refutes my claim in connection with the prior
commit that the issue only arises with use of LATERAL. That was just
wrong: some variants of SubLink always produce SubPlans.)
As with previous patch, back-patch to all supported branches.
Discussion: https://postgr.es/m/16213-871ac3bc208ecf23@postgresql.org
jsonb_set_lax() is the same as jsonb_set, except that it takes and extra
argument that specifies what to do if the value argument is NULL. The
default is 'use_json_null'. Other possibilities are 'raise_exception',
'return_target' and 'delete_key', all these behaviours having been
suggested as reasonable by various users.
Discussion: https://postgr.es/m/375873e2-c957-3a8d-64f9-26c43c2b16e7@2ndQuadrant.com
Reviewed by: Pavel Stehule
We've had numerous bug reports about how (1) IF NOT EXISTS clauses in
ALTER TABLE don't behave as-expected, and (2) combining certain actions
into one ALTER TABLE doesn't work, though executing the same actions as
separate statements does. This patch cleans up all of the cases so far
reported from the field, though there are still some oddities associated
with identity columns.
The core problem behind all of these bugs is that we do parse analysis
of ALTER TABLE subcommands too soon, before starting execution of the
statement. The root of the bugs in group (1) is that parse analysis
schedules derived commands (such as a CREATE SEQUENCE for a serial
column) before it's known whether the IF NOT EXISTS clause should cause
a subcommand to be skipped. The root of the bugs in group (2) is that
earlier subcommands may change the catalog state that later subcommands
need to be parsed against.
Hence, postpone parse analysis of ALTER TABLE's subcommands, and do
that one subcommand at a time, during "phase 2" of ALTER TABLE which
is the phase that does catalog rewrites. Thus the catalog effects
of earlier subcommands are already visible when we analyze later ones.
(The sole exception is that we do parse analysis for ALTER COLUMN TYPE
subcommands during phase 1, so that their USING expressions can be
parsed against the table's original state, which is what we need.
Arguably, these bugs stem from falsely concluding that because ALTER
COLUMN TYPE must do early parse analysis, every other command subtype
can too.)
This means that ALTER TABLE itself must deal with execution of any
non-ALTER-TABLE derived statements that are generated by parse analysis.
Add a suitable entry point to utility.c to accept those recursive
calls, and create a struct to pass through the information needed by
the recursive call, rather than making the argument lists of
AlterTable() and friends even longer.
Getting this to work correctly required a little bit of fiddling
with the subcommand pass structure, in particular breaking up
AT_PASS_ADD_CONSTR into multiple passes. But otherwise it's mostly
a pretty straightforward application of the above ideas.
Fixing the residual issues for identity columns requires refactoring of
where the dependency link from an identity column to its sequence gets
set up. So that seems like suitable material for a separate patch,
especially since this one is pretty big already.
Discussion: https://postgr.es/m/10365.1558909428@sss.pgh.pa.us
This uses the progress reporting infrastructure added by c16dc1aca5,
adding support for ANALYZE.
Co-authored-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Co-authored-by: Tatsuro Yamada <tatsuro.yamada.tf@nttcom.co.jp>
Reviewed-by: Julien Rouhaud, Robert Haas, Anthony Nowocien, Kyotaro Horiguchi,
Vignesh C, Amit Langote
A view with conditional INSTEAD rules and no unconditional INSTEAD
rules or INSTEAD OF triggers is not auto-updatable. Previously we
relied on a check in the executor to catch this, but that's
problematic since the planner may fail to properly handle such a query
and thus return a particularly unhelpful error to the user, before
reaching the executor check.
Instead, trap this in the rewriter and report the correct error there.
Doing so also allows us to include more useful error detail than the
executor check can provide. This doesn't change the existing behaviour
of updatable views; it merely ensures that useful error messages are
reported when a view isn't updatable.
Per report from Pengzhou Tang, though not adopting that suggested fix.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/CAG4reAQn+4xB6xHJqWdtE0ve_WqJkdyCV4P=trYr4Kn8_3_PEA@mail.gmail.com
Previously, the core scanner's yy_transition[] array had 37045 elements.
Since that number is larger than INT16_MAX, Flex generated the array to
contain 32-bit integers. By reimplementing some of the bulkier scanner
rules, this patch reduces the array to 20495 elements. The much smaller
total length, combined with the consequent use of 16-bit integers for
the array elements reduces the binary size by over 200kB. This was
accomplished in two ways:
1. Consolidate handling of quote continuations into a new start condition,
rather than duplicating that logic for five different string types.
2. Treat Unicode strings and identifiers followed by a UESCAPE sequence
as three separate tokens, rather than one. The logic to de-escape
Unicode strings is moved to the filter code in parser.c, which already
had the ability to provide special processing for token sequences.
While we could have implemented the conversion in the grammar, that
approach was rejected for performance and maintainability reasons.
Performance in microbenchmarks of raw parsing seems equal or slightly
faster in most cases, and it's reasonable to expect that in real-world
usage (with more competition for the CPU cache) there will be a larger
win. The exception is UESCAPE sequences; lexing those is about 10%
slower, primarily because the scanner now has to be called three times
rather than one. This seems acceptable since that feature is very
rarely used.
The psql and epcg lexers are likewise modified, primarily because we
want to keep them all in sync. Since those lexers don't use the
space-hogging -CF option, the space savings is much less, but it's
still good for perhaps 10kB apiece.
While at it, merge the ecpg lexer's handling of C-style comments used
in SQL and in C. Those have different rules regarding nested comments,
but since we already have the ability to keep track of the previous
start condition, we can use that to handle both cases within a single
start condition. This matches the core scanner more closely.
John Naylor
Discussion: https://postgr.es/m/CACPNZCvaoa3EgVWm5yZhcSTX6RAtaLgniCPcBVOCwm8h3xpWkw@mail.gmail.com
Tom Lane
Tomas Vondra
Thomas Munro
Michael Paquier
Noah Misch
Fujii Masao
David Rowley
Peter Eisentraut
Alexander Korotkov
Dean Rasheed
Jeff Davis
Andres Freund
Alvaro Herrera
Peter Geoghegan
Andrew Gierth
Amit Kapila
Andrew Dunstan