This allows the user to create duplicates of existing replication slots,
either logical or physical, and even changing properties such as whether
they are temporary or the output plugin used.
There are multiple uses for this, such as initializing multiple replicas
using the slot for one base backup; when doing investigation of logical
replication issues; and to select a different output plugins.
Author: Masahiko Sawada
Reviewed-by: Michael Paquier, Andres Freund, Petr Jelinek
Discussion: https://postgr.es/m/CAD21AoAm7XX8y_tOPP6j4Nzzch12FvA1wPqiO690RCk+uYVstg@mail.gmail.com
Previously it was allowed to set default_table_access_method to an
empty string. That makes sense for default_tablespace, where that was
copied from, as it signals falling back to the database's default
tablespace. As there is no equivalent for table AMs, forbid that.
Also make sure to throw a usable error when creating a table using an
index AM, by using get_am_type_oid() to implement get_table_am_oid()
instead of a separate copy. Previously we'd error out only later, in
GetTableAmRoutine().
Thirdly remove GetTableAmRoutineByAmId() - it was only used in an
earlier version of 8586bf7ed8.
Add tests for the above (some for index AMs as well).
This adds table_multi_insert(), and converts COPY FROM, the only user
of heap_multi_insert, to it.
A simple conversion of COPY FROM use slots would have yielded a
slowdown when inserting into a partitioned table for some
workloads. Different partitions might need different slots (both slot
types and their descriptors), and dropping / creating slots when
there's constant partition changes is measurable.
Thus instead revamp the COPY FROM buffering for partitioned tables to
allow to buffer inserts into multiple tables, flushing only when
limits are reached across all partition buffers. By only dropping
slots when there've been inserts into too many different partitions,
the aforementioned overhead is gone. By allowing larger batches, even
when there are frequent partition changes, we actuall speed such cases
up significantly.
By using slots COPY of very narrow rows into unlogged / temporary
might slow down very slightly (due to the indirect function calls).
Author: David Rowley, Andres Freund, Haribabu Kommi
Discussion:
https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.dehttps://postgr.es/m/20190327054923.t3epfuewxfqdt22e@alap3.anarazel.de
This commit adds a new reloption, vacuum_index_cleanup, which
controls whether index cleanup is performed for a particular
relation by default. It also adds a new option to the VACUUM
command, INDEX_CLEANUP, which can be used to override the
reloption. If neither the reloption nor the VACUUM option is
used, the default is true, as before.
Masahiko Sawada, reviewed and tested by Nathan Bossart, Alvaro
Herrera, Kyotaro Horiguchi, Darafei Praliaskouski, and me.
The wording of the documentation is mostly due to me.
Discussion: http://postgr.es/m/CAD21AoAt5R3DNUZSjOoXDUY=naYPUOuffVsRzuTYMz29yLzQCA@mail.gmail.com
The be_gssapi_get_* prototypes were put close to similar ones for SSL-
but a bit too close since that meant they ended up only being included
for SSL-enabled builds. Move those to be under ENABLE_GSS instead.
Pointed out by Tom.
Previously, md.c and checkpointer.c were tightly integrated so that
fsync calls could be handed off and processed in the background.
Introduce a system of callbacks and file tags, so that other modules
can hand off fsync work in the same way.
For now only md.c uses the new interface, but other users are being
proposed. Since there may be use cases that are not strictly SMGR
implementations, use a new function table for sync handlers rather
than extending the traditional SMGR one.
Instead of using a bitmapset of segment numbers for each RelFileNode
in the checkpointer's hash table, make the segment number part of the
key. This requires sending explicit "forget" requests for every
segment individually when relations are dropped, but suits the file
layout schemes of proposed future users better (ie sparse or high
segment numbers).
Author: Shawn Debnath and Thomas Munro
Reviewed-by: Thomas Munro, Andres Freund
Discussion: https://postgr.es/m/CAEepm=2gTANm=e3ARnJT=n0h8hf88wqmaZxk0JYkxw+b21fNrw@mail.gmail.com
This adds documentation about the user oriented parts of table access
methods (i.e. the default_table_access_method GUC and the USING clause
for CREATE TABLE etc), adds a basic chapter about the table access
method interface, and adds a note to storage.sgml that it's contents
don't necessarily apply for non-builtin AMs.
Author: Haribabu Kommi and Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
postmaster startup scrutinizes any shared memory segment recorded in
postmaster.pid, exiting if that segment matches the current data
directory and has an attached process. When the postmaster.pid file was
missing, a starting postmaster used weaker checks. Change to use the
same checks in both scenarios. This increases the chance of a startup
failure, in lieu of data corruption, if the DBA does "kill -9 `head -n1
postmaster.pid` && rm postmaster.pid && pg_ctl -w start". A postmaster
will no longer recycle segments pertaining to other data directories.
That's good for production, but it's bad for integration tests that
crash a postmaster and immediately delete its data directory. Such a
test now leaks a segment indefinitely. No "make check-world" test does
that. win32_shmem.c already avoided all these problems. In 9.6 and
later, enhance PostgresNode to facilitate testing. Back-patch to 9.4
(all supported versions).
Reviewed by Daniel Gustafsson and Kyotaro HORIGUCHI.
Discussion: https://postgr.es/m/20130911033341.GD225735@tornado.leadboat.com
Query planning is affected by a number of configuration options, and it
may be crucial to know which of those options were set to non-default
values. With this patch you can say EXPLAIN (SETTINGS ON) to include
that information in the query plan. Only options affecting planning,
with values different from the built-in default are printed.
This patch also adds auto_explain.log_settings option, providing the
same capability in auto_explain module.
Author: Tomas Vondra
Reviewed-by: Rafia Sabih, John Naylor
Discussion: https://postgr.es/m/e1791b4c-df9c-be02-edc5-7c8874944be0@2ndquadrant.com
This is useful to obtain a view of the different transaction types in an
application, regardless of the durations of the statements each runs.
Author: Adrien Nayrat
Reviewed-by: Masahiko Sawada, Hayato Kuroda, Andres Freund
Commit ea4e1c0e8f resolved issues with memory alignment in serialized
pg_mcv_list values, but it required copying data to/from the varlena
buffer during serialization and deserialization. As the MCV lits may
be fairly large, the overhead (memory consumption, CPU usage) can get
rather significant too.
This change tweaks the serialization format so that the alignment is
correct with respect to the varlena value, and so the parts may be
accessed directly without copying the data.
Catversion bump, as it affects existing pg_statistic_ext data.
On both the frontend and backend, prepare for GSSAPI encryption
support by moving common code for error handling into a separate file.
Fix a TODO for handling multiple status messages in the process.
Eliminate the OIDs, which have not been needed for some time.
Add frontend and backend encryption support functions. Keep the
context initiation for authentication-only separate on both the
frontend and backend in order to avoid concerns about changing the
requested flags to include encryption support.
In postmaster, pull GSSAPI authorization checking into a shared
function. Also share the initiator name between the encryption and
non-encryption codepaths.
For HBA, add "hostgssenc" and "hostnogssenc" entries that behave
similarly to their SSL counterparts. "hostgssenc" requires either
"gss", "trust", or "reject" for its authentication.
Similarly, add a "gssencmode" parameter to libpq. Supported values are
"disable", "require", and "prefer". Notably, negotiation will only be
attempted if credentials can be acquired. Move credential acquisition
into its own function to support this behavior.
Add a simple pg_stat_gssapi view similar to pg_stat_ssl, for monitoring
if GSSAPI authentication was used, what principal was used, and if
encryption is being used on the connection.
Finally, add documentation for everything new, and update existing
documentation on connection security.
Thanks to Michael Paquier for the Windows fixes.
Author: Robbie Harwood, with changes to the read/write functions by me.
Reviewed in various forms and at different times by: Michael Paquier,
Andres Freund, David Steele.
Discussion: https://www.postgresql.org/message-id/flat/jlg1tgq1ktm.fsf@thriss.redhat.com
Previously, while primary keys could be made on partitioned tables, it
was not possible to define foreign keys that reference those primary
keys. Now it is possible to do that.
Author: Álvaro Herrera
Reviewed-by: Amit Langote, Jesper Pedersen
Discussion: https://postgr.es/m/20181102234158.735b3fevta63msbj@alvherre.pgsql
Instead of WAL-logging every modification during the build separately,
first build the index without any WAL-logging, and make a separate pass
through the index at the end, to write all pages to the WAL. This
significantly reduces the amount of WAL generated, and is usually also
faster, despite the extra I/O needed for the extra scan through the index.
WAL generated this way is also faster to replay.
For GiST, the LSN-NSN interlock makes this a little tricky. All pages must
be marked with a valid (i.e. non-zero) LSN, so that the parent-child
LSN-NSN interlock works correctly. We now use magic value 1 for that during
index build. Change the fake LSN counter to begin from 1000, so that 1 is
safely smaller than any real or fake LSN. 2 would've been enough for our
purposes, but let's reserve a bigger range, in case we need more special
values in the future.
Author: Anastasia Lubennikova, Andrey V. Lepikhov
Reviewed-by: Heikki Linnakangas, Dmitry Dolgov
This uses the progress reporting infrastructure added by c16dc1aca5,
adding support for CREATE INDEX and CREATE INDEX CONCURRENTLY.
There are two pieces to this: one is index-AM-agnostic, and the other is
AM-specific. The latter is fairly elaborate for btrees, including
reportage for parallel index builds and the separate phases that btree
index creation uses; other index AMs, which are much simpler in their
building procedures, have simplistic reporting only, but that seems
sufficient, at least for non-concurrent builds.
The index-AM-agnostic part is fairly complete, providing insight into
the CONCURRENTLY wait phases as well as block-based progress during the
index validation table scan. (The index validation index scan requires
patching each AM, which has not been included here.)
Reviewers: Rahila Syed, Pavan Deolasee, Tatsuro Yamada
Discussion: https://postgr.es/m/20181220220022.mg63bhk26zdpvmcj@alvherre.pgsql
When asked for a slice of a TOAST entry, decompress enough to return the
slice instead of decompressing the entire object.
For use cases where the slice is at, or near, the beginning of the entry,
this avoids a lot of unnecessary decompression work.
This changes the signature of pglz_decompress() by adding a boolean to
indicate if it's ok for the call to finish before consuming all of the
source or destination buffers.
Author: Paul Ramsey
Reviewed-By: Rafia Sabih, Darafei Praliaskouski, Regina Obe
Discussion: https://postgr.es/m/CACowWR07EDm7Y4m2kbhN_jnys%3DBBf9A6768RyQdKm_%3DNpkcaWg%40mail.gmail.com
The upper-planner pathification allows FDWs to arrange to push down
different types of upper-stage operations to the remote side. This
commit teaches postgres_fdw to do it for the (FINAL, NULL) upperrel,
which is responsible for doing LockRows, LIMIT, and/or ModifyTable.
This provides the ability for postgres_fdw to handle SELECT commands
so that it 1) skips the LockRows step (if any) (note that this is
safe since it performs early locking) and 2) pushes down the LIMIT
and/or OFFSET restrictions (if any) to the remote side. This doesn't
handle the INSERT/UPDATE/DELETE cases.
Author: Etsuro Fujita
Reviewed-By: Antonin Houska and Jeff Janes
Discussion: https://postgr.es/m/87pnz1aby9.fsf@news-spur.riddles.org.uk
On at least ZFS, it can be beneficial to create new WAL files every
time and not to bother zero-filling them. Since it's not clear which
other filesystems might benefit from one or both of those things,
add individual GUCs to control those two behaviors independently and
make only very general statements in the docs.
Author: Jerry Jelinek, with some adjustments by Thomas Munro
Reviewed-by: Alvaro Herrera, Andres Freund, Tomas Vondra, Robert Haas and others
Discussion: https://postgr.es/m/CACPQ5Fo00QR7LNAcd1ZjgoBi4y97%2BK760YABs0vQHH5dLdkkMA%40mail.gmail.com
This replaces the previous calls of heap_sync() in places using
bulk-insert. By passing in the flags used for bulk-insert the AM can
decide (first at insert time and then during the finish call) which of
the optimizations apply to it, and what operations are necessary to
finish a bulk insert operation.
Also change HEAP_INSERT_* flags to TABLE_INSERT, and rename hi_options
to ti_options.
These changes are made even in copy.c, which hasn't yet been converted
to tableam. There's no harm in doing so.
Author: Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
This unifies the various ad hoc logging (message printing, error
printing) systems used throughout the command-line programs.
Features:
- Program name is automatically prefixed.
- Message string does not end with newline. This removes a common
source of inconsistencies and omissions.
- Additionally, a final newline is automatically stripped, simplifying
use of PQerrorMessage() etc., another common source of mistakes.
- I converted error message strings to use %m where possible.
- As a result of the above several points, more translatable message
strings can be shared between different components and between
frontends and backend, without gratuitous punctuation or whitespace
differences.
- There is support for setting a "log level". This is not meant to be
user-facing, but can be used internally to implement debug or
verbose modes.
- Lazy argument evaluation, so no significant overhead if logging at
some level is disabled.
- Some color in the messages, similar to gcc and clang. Set
PG_COLOR=auto to try it out. Some colors are predefined, but can be
customized by setting PG_COLORS.
- Common files (common/, fe_utils/, etc.) can handle logging much more
simply by just using one API without worrying too much about the
context of the calling program, requiring callbacks, or having to
pass "progname" around everywhere.
- Some programs called setvbuf() to make sure that stderr is
unbuffered, even on Windows. But not all programs did that. This
is now done centrally.
Soft goals:
- Reduces vertical space use and visual complexity of error reporting
in the source code.
- Encourages more deliberate classification of messages. For example,
in some cases it wasn't clear without analyzing the surrounding code
whether a message was meant as an error or just an info.
- Concepts and terms are vaguely aligned with popular logging
frameworks such as log4j and Python logging.
This is all just about printing stuff out. Nothing affects program
flow (e.g., fatal exits). The uses are just too varied to do that.
Some existing code had wrappers that do some kind of print-and-exit,
and I adapted those.
I tried to keep the output mostly the same, but there is a lot of
historical baggage to unwind and special cases to consider, and I
might not always have succeeded. One significant change is that
pg_rewind used to write all error messages to stdout. That is now
changed to stderr.
Reviewed-by: Donald Dong <xdong@csumb.edu>
Reviewed-by: Arthur Zakirov <a.zakirov@postgrespro.ru>
Discussion: https://www.postgresql.org/message-id/flat/6a609b43-4f57-7348-6480-bd022f924310@2ndquadrant.com
This commit makes existing GIN operator classes jsonb_ops and json_path_ops
support "jsonb @@ jsonpath" and "jsonb @? jsonpath" operators. Basic idea is
to extract statements of following form out of jsonpath.
key1.key2. ... .keyN = const
The rest of jsonpath is rechecked from heap.
Catversion is bumped.
Discussion: https://postgr.es/m/fcc6fc6a-b497-f39a-923d-aa34d0c588e8%402ndQuadrant.com
Author: Nikita Glukhov, Alexander Korotkov
Reviewed-by: Jonathan Katz, Pavel Stehule
This moves bitmap heap scan support to below an optional tableam
callback. It's optional as the whole concept of bitmap heapscans is
fairly block specific.
This basically moves the work previously done in bitgetpage() into the
new scan_bitmap_next_block callback, and the direct poking into the
buffer done in BitmapHeapNext() into the new scan_bitmap_next_tuple()
callback.
The abstraction is currently somewhat leaky because
nodeBitmapHeapscan.c's prefetching and visibilitymap based logic
remains - it's likely that we'll later have to move more into the
AM. But it's not trivial to do so without introducing a significant
amount of code duplication between the AMs, so that's a project for
later.
Note that now nodeBitmapHeapscan.c and the associated node types are a
bit misnamed. But it's not clear whether renaming wouldn't be a cure
worse than the disease. Either way, that'd be best done in a separate
commit.
Author: Andres Freund
Reviewed-By: Robert Haas (in an older version)
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
This moves sample scan support to below tableam. It's not optional as
there is, in contrast to e.g. bitmap heap scans, no alternative way to
perform tablesample queries. If an AM can't deal with the block based
API, it will have to throw an ERROR.
The tableam callbacks for this are block based, but given the current
TsmRoutine interface, that seems to be required.
The new interface doesn't require TsmRoutines to perform visibility
checks anymore - that requires the TsmRoutine to know details about
the AM, which we want to avoid. To continue to allow taking the
returned number of tuples account SampleScanState now has a donetuples
field (which previously e.g. existed in SystemRowsSamplerData), which
is only incremented after the visibility check succeeds.
Author: Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
This just moves the table/matview[/toast] determination of relation
size to a callback, and uses a copy of the existing logic to implement
that callback for heap.
It probably would make sense to also move the index specific logic
into a callback, so the metapage handling (and probably more) can be
index specific. But that's a separate task.
Author: Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
This is a relatively straightforward move of the current
implementation to sit below tableam. As the current analyze sampling
implementation is pretty inherently block based, the tableam analyze
interface is as well. It might make sense to generalize that at some
point, but that seems like a larger project that shouldn't be
undertaken at the same time as the introduction of tableam.
Author: Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
Previously, the planner created RangeTblEntry and RelOptInfo structs
for every partition of a partitioned table, even though many of them
might later be deemed uninteresting thanks to partition pruning logic.
This incurred significant overhead when there are many partitions.
Arrange to postpone creation of these data structures until after
we've processed the query enough to identify restriction quals for
the partitioned table, and then apply partition pruning before not
after creation of each partition's data structures. In this way
we need not open the partition relations at all for partitions that
the planner has no real interest in.
For queries that can be proven at plan time to access only a small
number of partitions, this patch improves the practical maximum
number of partitions from under 100 to perhaps a few thousand.
Amit Langote, reviewed at various times by Dilip Kumar, Jesper Pedersen,
Yoshikazu Imai, and David Rowley
Discussion: https://postgr.es/m/9d7c5112-cb99-6a47-d3be-cf1ee6862a1d@lab.ntt.co.jp
This is an SQL-standard feature that allows creating columns that are
computed from expressions rather than assigned, similar to a view or
materialized view but on a column basis.
This implements one kind of generated column: stored (computed on
write). Another kind, virtual (computed on read), is planned for the
future, and some room is left for it.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/b151f851-4019-bdb1-699e-ebab07d2f40a@2ndquadrant.com
Blind attempt at fixing ia64, hppa an sparc builds.
The serialized representation of MCV lists did not enforce proper memory
alignment for internal fields, resulting in deserialization issues on
platforms that are more sensitive to this (ia64, sparc and hppa).
This forces a catalog version bump, because the layout of serialized
pg_mcv_list changes.
Broken since 7300a699.
This adds the CONCURRENTLY option to the REINDEX command. A REINDEX
CONCURRENTLY on a specific index creates a new index (like CREATE
INDEX CONCURRENTLY), then renames the old index away and the new index
in place and adjusts the dependencies, and then drops the old
index (like DROP INDEX CONCURRENTLY). The REINDEX command also has
the capability to run its other variants (TABLE, DATABASE) with the
CONCURRENTLY option (but not SYSTEM).
The reindexdb command gets the --concurrently option.
Author: Michael Paquier, Andreas Karlsson, Peter Eisentraut
Reviewed-by: Andres Freund, Fujii Masao, Jim Nasby, Sergei Kornilov
Discussion: https://www.postgresql.org/message-id/flat/60052986-956b-4478-45ed-8bd119e9b9cf%402ndquadrant.com#74948a1044c56c5e817a5050f554ddee
This moves the responsibility for:
- creating the storage necessary for a relation, including creating a
new relfilenode for a relation with existing storage
- non-transactional truncation of a relation
- VACUUM FULL / CLUSTER's rewrite of a table
below tableam.
This is fairly straight forward, with a bit of complexity smattered in
to move the computation of xid / multixid horizons below the AM, as
they don't make sense for every table AM.
Author: Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
There were multiple issues in deserialization of pg_mcv_list values.
Firstly, the data is loaded from syscache, but the deserialization was
performed after ReleaseSysCache(), at which point the data might have
already disappeared. Fixed by moving the calls in statext_mcv_load,
and using the same NULL-handling code as existing stats.
Secondly, the deserialized representation used pointers into the
serialized representation. But that is also unsafe, because the data
may disappear at any time. Fixed by reworking and simplifying the
deserialization code to always copy all the data.
And thirdly, when deserializing values for types passed by value, the
code simply did memcpy(d,s,typlen) which however does not work on
bigendian machines. Fixed by using fetch_att/store_att_byval.
Provide GetTopFullTransactionId() and GetCurrentFullTransactionId().
The intended users of these interfaces are access methods that use
xids for visibility checks but don't want to have to go back and
"freeze" existing references some time later before the 32 bit xid
counter wraps around.
Use a new struct to serialize the transaction state for parallel
query, because FullTransactionId doesn't fit into the previous
serialization scheme very well.
Author: Thomas Munro
Reviewed-by: Heikki Linnakangas
Discussion: https://postgr.es/m/CAA4eK1%2BMv%2Bmb0HFfWM9Srtc6MVe160WFurXV68iAFMcagRZ0dQ%40mail.gmail.com
Instead of inferring epoch progress from xids and checkpoints,
introduce a 64 bit FullTransactionId type and use it to track xid
generation. This fixes an unlikely bug where the epoch is reported
incorrectly if the range of active xids wraps around more than once
between checkpoints.
The only user-visible effect of this commit is to correct the epoch
used by txid_current() and txid_status(), also visible with
pg_controldata, in those rare circumstances. It also creates some
basic infrastructure so that later patches can use 64 bit
transaction IDs in more places.
The new type is a struct that we pass by value, as a form of strong
typedef. This prevents the sort of accidental confusion between
TransactionId and FullTransactionId that would be possible if we
were to use a plain old uint64.
Author: Thomas Munro
Reported-by: Amit Kapila
Reviewed-by: Andres Freund, Tom Lane, Heikki Linnakangas
Discussion: https://postgr.es/m/CAA4eK1%2BMv%2Bmb0HFfWM9Srtc6MVe160WFurXV68iAFMcagRZ0dQ%40mail.gmail.com
To support building indexes over tables of different AMs, the scans to
do so need to be routed through the table AM. While moving a fair
amount of code, nearly all the changes are just moving code to below a
callback.
Currently the range based interface wouldn't make much sense for non
block based table AMs. But that seems aceptable for now.
Author: Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
The MCV build should always call get_mincount_for_mcv_list(), as the
there is no other logic to decide whether the MCV list represents all
the data. So just remove the (ngroups > nitems) condition.
Also, when building MCV lists, the number of items was limited by the
statistics target (i.e. up to 10000). But when deserializing the MCV
list, a different value (8192) was used to check the input, causing
an error. Simply ensure that the same value is used in both places.
This should have been included in 7300a69950, but I forgot to include it
in that commit.
Introduce a third extended statistic type, supported by the CREATE
STATISTICS command - MCV lists, a generalization of the statistic
already built and used for individual columns.
Compared to the already supported types (n-distinct coefficients and
functional dependencies), MCV lists are more complex, include column
values and allow estimation of much wider range of common clauses
(equality and inequality conditions, IS NULL, IS NOT NULL etc.).
Similarly to the other types, a new pseudo-type (pg_mcv_list) is used.
Author: Tomas Vondra
Reviewed-by: Dean Rasheed, David Rowley, Mark Dilger, Alvaro Herrera
Discussion: https://postgr.es/m/dfdac334-9cf2-2597-fb27-f0fb3753f435@2ndquadrant.com
In the dim past, the planner kept the fully-processed version of the query
targetlist (the result of preprocess_targetlist) in grouping_planner's
local variable "tlist", and only grudgingly passed it to individual other
routines as needed. Later we discovered a need to still have it available
after grouping_planner finishes, and invented the root->processed_tlist
field for that purpose, but it wasn't used internally to grouping_planner;
the tlist was still being passed around separately in the same places as
before.
Now comes a proposed patch to allow appendrel expansion to add entries
to the processed tlist, well after preprocess_targetlist has finished
its work. To avoid having to pass around the tlist explicitly, it's
proposed to allow appendrel expansion to modify root->processed_tlist.
That makes aliasing the tlist with assorted parameters and local
variables really scary. It would accidentally work as long as the
tlist is initially nonempty, because then the List header won't move
around, but it's not exactly hard to think of ways for that to break.
Aliased values are poor programming practice anyway.
Hence, get rid of local variables and parameters that can be identified
with root->processed_tlist, in favor of just using that field directly.
And adjust comments to match. (Some of the new comments speak as though
it's already possible for appendrel expansion to modify the tlist; that's
not true yet, but will happen in a later patch.)
Discussion: https://postgr.es/m/9d7c5112-cb99-6a47-d3be-cf1ee6862a1d@lab.ntt.co.jp
When invoked for the first time in a session, current_schema() and
current_schemas() can finish by creating a temporary schema. Currently
those functions are parallel-safe, however if for a reason or another
they get launched across multiple parallel workers, they would fail when
attempting to create a temporary schema as temporary contexts are not
supported in this case.
The original issue has been spotted by buildfarm members crake and
lapwing, after commit c5660e0 has introduced the first regression tests
based on current_schema() in the tree. After that, 396676b has
introduced a workaround to avoid parallel plans but that was not
completely right either.
Catversion is bumped.
Author: Michael Paquier
Reviewed-by: Daniel Gustafsson
Discussion: https://postgr.es/m/20190118024618.GF1883@paquier.xyz
Relations dropped in a single transaction are tracked in a list of
unowned relations. With large number of dropped relations this resulted
in poor performance at the end of a transaction, when the relations are
removed from the singly linked list one by one.
Commit b4166911 attempted to address this issue (particularly when it
happens during recovery) by removing the relations in a reverse order,
resulting in O(1) lookups in the list of unowned relations. This did
not work reliably, though, and it was possible to trigger the O(N^2)
behavior in various ways.
Instead of trying to remove the relations in a specific order with
respect to the linked list, which seems rather fragile, switch to a
regular doubly linked. That allows us to remove relations cheaply no
matter where in the list they are.
As b4166911 was a bugfix, backpatched to all supported versions, do the
same thing here.
Reviewed-by: Alvaro Herrera
Discussion: https://www.postgresql.org/message-id/flat/80c27103-99e4-1d0c-642c-d9f3b94aaa0a%402ndquadrant.com
Backpatch-through: 9.4
Previously the xid horizon was only computed during WAL replay. That
had two major problems:
1) It relied on knowing what the table pointed to looks like. That was
easy enough before the introducing of tableam (we knew it had to be
heap, although some trickery around logging the heap relfilenodes
was required). But to properly handle table AMs we need
per-database catalog access to look up the AM handler, which
recovery doesn't allow.
2) Not knowing the xid horizon also makes it hard to support logical
decoding on standbys. When on a catalog table, we need to be able
to conflict with slots that have an xid horizon that's too old. But
computing the horizon by visiting the heap only works once
consistency is reached, but we always need to be able to detect
conflicts.
There's also a secondary problem, in that the current method performs
redundant work on every standby. But that's counterbalanced by
potentially computing the value when not necessary (either because
there's no standby, or because there's no connected backends).
Solve 1) and 2) by moving computation of the xid horizon to the
primary and by involving tableam in the computation of the horizon.
To address the potentially increased overhead, increase the efficiency
of the xid horizon computation for heap by sorting the tids, and
eliminating redundant buffer accesses. When prefetching is available,
additionally perform prefetching of buffers. As this is more of a
maintenance task, rather than something routinely done in every read
only query, we add an arbitrary 10 to the effective concurrency -
thereby using IO concurrency, when not globally enabled. That's
possibly not the perfect formula, but seems good enough for now.
Bumps WAL format, as latestRemovedXid is now part of the records, and
the heap's relfilenode isn't anymore.
Author: Andres Freund, Amit Khandekar, Robert Haas
Reviewed-By: Robert Haas
Discussion:
https://postgr.es/m/20181212204154.nsxf3gzqv3gesl32@alap3.anarazel.dehttps://postgr.es/m/20181214014235.dal5ogljs3bmlq44@alap3.anarazel.dehttps://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
Up to now, otherrel RelOptInfos were built at the same time as baserel
RelOptInfos, thanks to recursion in build_simple_rel(). However,
nothing in query_planner's preprocessing cares at all about otherrels,
only baserels, so we don't really need to build them until just before
we enter make_one_rel. This has two benefits:
* create_lateral_join_info did a lot of extra work to propagate
lateral-reference information from parents to the correct children.
But if we delay creation of the children till after that, it's
trivial (and much harder to break, too).
* Since we have all the restriction quals correctly assigned to
parent appendrels by this point, it'll be possible to do plan-time
pruning and never make child RelOptInfos at all for partitions that
can be pruned away. That's not done here, but will be later on.
Amit Langote, reviewed at various times by Dilip Kumar, Jesper Pedersen,
Yoshikazu Imai, and David Rowley
Discussion: https://postgr.es/m/9d7c5112-cb99-6a47-d3be-cf1ee6862a1d@lab.ntt.co.jp
After 71bdc99d0d, "tableam: Add helper for indexes to check if a
corresponding table tuples exist." there's no in-core user left. As
there's unlikely to be an external user, and such an external user
could easily be adjusted to use table_index_fetch_tuple_check(),
remove heap_hot_search().
Per complaint from Peter Geoghegan
Author: Andres Freund
Discussion: https://postgr.es/m/CAH2-Wzn0Oq4ftJrTqRAsWy2WGjv0QrJcwoZ+yqWsF_Z5vjUBFw@mail.gmail.com
This primarily is to allow WHERE CURRENT OF to continue to work as it
currently does. It's not clear to me that these semantics make sense
for every AM, but it works for the in-core heap, and the out of core
zheap. We can refine it further at a later point if necessary.
Author: Andres Freund
Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
Alvaro Herrera