Expose the count of index searches/index descents in EXPLAIN ANALYZE's
output for index scan/index-only scan/bitmap index scan nodes. This
information is particularly useful with scans that use ScalarArrayOp
quals, where the number of index searches can be unpredictable due to
implementation details that interact with physical index characteristics
(at least with nbtree SAOP scans, since Postgres 17 commit 5bf748b8).
The information shown also provides useful context when EXPLAIN ANALYZE
runs a plan with an index scan node that successfully applied the skip
scan optimization (set to be added to nbtree by an upcoming patch).
The instrumentation works by teaching all index AMs to increment a new
nsearches counter whenever a new index search begins. The counter is
incremented at exactly the same point that index AMs already increment
the pg_stat_*_indexes.idx_scan counter (we're counting the same event,
but at the scan level rather than the relation level). Parallel queries
have workers copy their local counter struct into shared memory when an
index scan node ends -- even when it isn't a parallel aware scan node.
An earlier version of this patch that only worked with parallel aware
scans became commit 5ead85fb (though that was quickly reverted by commit
d00107cd following "debug_parallel_query=regress" buildfarm failures).
Our approach doesn't match the approach used when tracking other index
scan related costs (e.g., "Rows Removed by Filter:"). It is comparable
to the approach used in similar cases involving costs that are only
readily accessible inside an access method, not from the executor proper
(e.g., "Heap Blocks:" output for a Bitmap Heap Scan, which was recently
enhanced to show per-worker costs by commit 5a1e6df3, using essentially
the same scheme as the one used here). It is necessary for index AMs to
have direct responsibility for maintaining the new counter, since the
counter might need to be incremented multiple times per amgettuple call
(or per amgetbitmap call). But it is also necessary for the executor
proper to manage the shared memory now used to transfer each worker's
counter struct to the leader.
Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-By: Tomas Vondra <tomas@vondra.me>
Reviewed-By: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Reviewed-By: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/CAH2-WzkRqvaqR2CTNqTZP0z6FuL4-3ED6eQB0yx38XBNj1v-4Q@mail.gmail.com
Discussion: https://postgr.es/m/CAH2-Wz=PKR6rB7qbx+Vnd7eqeB5VTcrW=iJvAsTsKbdG+kW_UA@mail.gmail.com
This reverts commit 5ead85fbc8.
This commit shows test failures with debug_parallel_query=regress. The
underlying issue needs to be debugged, so revert for now.
Expose the count of index searches/index descents in EXPLAIN ANALYZE's
output for index scan nodes. This information is particularly useful
with scans that use ScalarArrayOp quals, where the number of index scans
isn't predictable in advance (at least not with optimizations like the
one added to nbtree by Postgres 17 commit 5bf748b8). It will also be
useful when EXPLAIN ANALYZE shows details of an nbtree index scan that
uses skip scan optimizations set to be introduced by an upcoming patch.
The instrumentation works by teaching index AMs to increment a new
nsearches counter whenever a new index search begins. The counter is
incremented at exactly the same point that index AMs must already
increment the index's pg_stat_*_indexes.idx_scan counter (we're counting
the same event, but at the scan level rather than the relation level).
The new counter is stored in the scan descriptor (IndexScanDescData),
which explain.c reaches by going through the scan node's PlanState.
This approach doesn't match the approach used when tracking other index
scan specific costs (e.g., "Rows Removed by Filter:"). It is similar to
the approach used in other cases where we must track costs that are only
readily accessible inside an access method, and not from the executor
(e.g., "Heap Blocks:" output for a Bitmap Heap Scan). It is inherently
necessary to maintain a counter that can be incremented multiple times
during a single amgettuple call (or amgetbitmap call), and directly
exposing PlanState.instrument to index access methods seems unappealing.
Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Tomas Vondra <tomas@vondra.me>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-By: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Reviewed-By: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/CAH2-Wz=PKR6rB7qbx+Vnd7eqeB5VTcrW=iJvAsTsKbdG+kW_UA@mail.gmail.com
Discussion: https://postgr.es/m/CAH2-WzkRqvaqR2CTNqTZP0z6FuL4-3ED6eQB0yx38XBNj1v-4Q@mail.gmail.com
Stop comparing access method OID values against HASH_AM_OID and
BTREE_AM_OID, and instead check the IndexAmRoutine for an index to see
if it advertises its ability to perform the necessary ordering,
hashing, or cross-type comparing functionality. A field amcanorder
already existed, this uses it more widely. Fields amcanhash and
amcancrosscompare are added for the other purposes.
Author: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/E72EAA49-354D-4C2E-8EB9-255197F55330@enterprisedb.com
The type argument wasn't actually really necessary. It was a remnant
of converting the API of the gist strategy translation from using
opclass to using opfamily+opcintype (commits c09e5a6a01,
622f678c10). For looking up the gist translation function, we used
the convention "amproclefttype = amprocrighttype = opclass's
opcintype" (see pg_amproc.h). But each operator family should only
have one translation function, and getting the right type for the
lookup is sometimes cumbersome and fragile, so this is all
unnecessarily complicated.
To simplify this, change the gist stategy support procedure to take
"any", "any" as argument. (This is arbitrary but seems intuitive.
The alternative of using InvalidOid as argument(s) upsets various DDL
commands, so it's not practical.) Then we don't need opcintype for
the lookup, and we can remove it from all the API layers introduced by
commit c09e5a6a01.
This also adds some more documentation about the correct signature of
the gist support function and adds more checks in gistvalidate().
This was previously underspecified. (It relied implicitly on
convention mentioned above.)
Discussion: https://www.postgresql.org/message-id/flat/E72EAA49-354D-4C2E-8EB9-255197F55330@enterprisedb.com
For each Index AM, provide a mapping between operator strategies and
the system-wide generic concept of a comparison type. For example,
for btree, BTLessStrategyNumber maps to and from COMPARE_LT. Numerous
places in the planner and executor think directly in terms of btree
strategy numbers (and a few in terms of hash strategy numbers.) These
should be converted over subsequent commits to think in terms of
CompareType instead. (This commit doesn't make any use of this API
yet.)
Author: Mark Dilger <mark.dilger@enterprisedb.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://www.postgresql.org/message-id/flat/E72EAA49-354D-4C2E-8EB9-255197F55330@enterprisedb.com
Consistently use "Size" (or size_t, or in some places int64 or double)
as the type for variables holding memory allocation sizes. In most
places variables' data types were fine already, but we had an ancient
habit of computing bytes from kilobytes-units GUCs with code like
"work_mem * 1024L". That risks overflow on Win64 where they did not
make "long" as wide as "size_t". We worked around that by restricting
such GUCs' ranges, so you couldn't set work_mem et al higher than 2GB
on Win64. This patch removes that restriction, after replacing such
calculations with "work_mem * (Size) 1024" or variants of that.
It should be noted that this patch was constructed by searching
outwards from the GUCs that have MAX_KILOBYTES as upper limit.
So I can't positively guarantee there are no other places doing
memory-size arithmetic in int or long variables. I do however feel
pretty confident that increasing MAX_KILOBYTES on Win64 is safe now.
Also, nothing in our code should be dealing in multiple-gigabyte
allocations without authorization from a relevant GUC, so it seems
pretty likely that this search caught everything that could be at
risk of overflow.
Author: Vladlen Popolitov <v.popolitov@postgrespro.ru>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1a01f0-66ec2d80-3b-68487680@27595217
When we are building a hash index that is large enough to need
pre-sorting (larger than either maintenance_work_mem or NBuffers),
the initial sorting phase is interruptible, but the insertion
phase wasn't. Add the missing CHECK_FOR_INTERRUPTS().
Per bug #18616 from Alexander Lakhin. Back-patch to all
supported branches.
Pavel Borisov
Discussion: https://postgr.es/m/18616-acbb9e5caf41e964@postgresql.org
Remove redundant checks for locale->collate_is_c now that we always
have a valid pg_locale_t.
Also, remove pg_locale_deterministic() wrapper, which is no longer
useful after commit e9931bfb75. Just check the field directly,
consistent with other fields in pg_locale_t.
Author: Andreas Karlsson
Discussion: https://postgr.es/m/60929555-4709-40a7-b136-bcb44cff5a3c@proxel.se
hashvalidate(), which validates the signatures of support functions
for the hash AM, contained several hardcoded exceptions. For example,
hash/date_ops support function 1 was hashint4(), which would
ordinarily fail validation because the function argument is int4, not
date. But this works internally because int4 and date are of the same
size. There are several more exceptions like this that happen to work
and were allowed historically but would now fail the function
signature validation.
This patch removes those exceptions by providing new support functions
that have the proper declared signatures. They internally share most
of the code with the "wrong" functions they replace, so the behavior
is still the same.
With the exceptions gone, hashvalidate() is now simplified and relies
fully on check_amproc_signature().
hashvarlena() and hashvarlenaextended() are kept in pg_proc.dat
because some extensions currently use them to build hash functions for
their own types, and we need to keep exposing these functions as
"LANGUAGE internal" functions for that to continue to work.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/29c3b746-69e7-482a-b37c-dbbf7e5b009b@eisentraut.org
The index access methods all had similar code that copied the
passed-in scan keys to local storage. They all used memmove() for
that, which is not wrong, but it seems confusing not to use memcpy()
when that would work. Presumably, this was all once copied from
ancient code and never adjusted.
Discussion: https://www.postgresql.org/message-id/flat/f8c739d9-f48d-4187-b214-df3391ba41ab@eisentraut.org
Previously, passing NULL for pg_locale_t meant "use the libc provider
and the server environment". Now that the database collation is
represented as a proper pg_locale_t (not dependent on setlocale()),
remove special cases for NULL.
Leave wchar2char() and char2wchar() unchanged for now, because the
callers don't always have a libc-based pg_locale_t available.
Discussion: https://postgr.es/m/cfd9eb85-c52a-4ec9-a90e-a5e4de56e57d@eisentraut.org
Reviewed-by: Peter Eisentraut, Andreas Karlsson
aa5edbe379 has tweaked _hash_freeovflpage() so as the write buffer's
LSN is updated only when necessary, when REGBUF_NO_CHANGE is not used.
The replay code was not consistent with that, causing the write buffer's
LSN to be updated and its page to be marked as dirty even if the buffer
was registered in a "clean" state. This was possible for the case of a
squeeze record when there are no tuples to add to the write buffer, for
(is_prim_bucket_same_wrt && !is_prev_bucket_same_wrt).
I have performed some validation of this commit with
wal_consistency_checking and a change in WAL that logs REGBUF_NO_CHANGE
to a new BKPIMAGE_*. Thanks to that, it is possible to know at replay
if a buffer was clean when it was registered, then cross-checked the LSN
of the "clean" page copy coming from WAL with the LSN of the block once
the record has been replayed. This eats one bit in bimg_info, which is
not acceptable to be integrated as-is, but it could become handy in the
future. I didn't spot other areas than the one fixed by this commit at
the extent of what the main regression test suite covers.
As this is an oversight in aa5edbe379, no backpatch is required.
Reported-by: Zubeyr Eryilmaz
Author: Hayato Kuroda
Reviewed-by: Amit Kapila, Michael Paquier
Discussion: https://postgr.es/m/ZbyVVG_7eW3YD5-A@paquier.xyz
The new combined WAL record is now used for pruning, freezing and 2nd
pass of vacuum. This is in preparation for changing VACUUM to write a
combined prune+freeze record per page, instead of separate two
records. The new WAL record format now supports that, but the code
still always writes separate records for pruning and freezing.
This reserves separate XLOG_HEAP2_* info codes for when the pruning
record is emitted for on-access pruning or VACUUM, per Peter
Geoghegan's suggestion. The record format is identical, but having
separate info codes makes it easier analyze pruning and vacuuming with
pg_waldump.
The function to emit the new WAL record, log_heap_prune_and_freeze(),
is in pruneheap.c. The existing heap_log_freeze_plan() and its
subroutines are moved to pruneheap.c without changes, to keep them
together with log_heap_prune_and_freeze().
Author: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://www.postgresql.org/message-id/CAAKRu_azf-zH%3DDgVbquZ3tFWjMY1w5pO8m-TXJaMdri8z3933g@mail.gmail.com
Discussion: https://www.postgresql.org/message-id/CAAKRu_b2oE4GL%3Dq4g9mcByS9yT7wTQvEH9OLpabj28e%2BWKFi2A@mail.gmail.com
as determined by include-what-you-use (IWYU)
While IWYU also suggests to *add* a bunch of #include's (which is its
main purpose), this patch does not do that. In some cases, a more
specific #include replaces another less specific one.
Some manual adjustments of the automatic result:
- IWYU currently doesn't know about includes that provide global
variable declarations (like -Wmissing-variable-declarations), so
those includes are being kept manually.
- All includes for port(ability) headers are being kept for now, to
play it safe.
- No changes of catalog/pg_foo.h to catalog/pg_foo_d.h, to keep the
patch from exploding in size.
Note that this patch touches just *.c files, so nothing declared in
header files changes in hidden ways.
As a small example, in src/backend/access/transam/rmgr.c, some IWYU
pragma annotations are added to handle a special case there.
Discussion: https://www.postgresql.org/message-id/flat/af837490-6b2f-46df-ba05-37ea6a6653fc%40eisentraut.org
Commit 861f86beea used REGBUF_NO_CHANGE at one of the places in the hash
index to register the clean buffers but forgot to avoid setting LSN in
that case.
Reported-by: Michael Paquier
Author: Kuroda Hayato
Reviewed-by: Amit Kapila, Michael Paquier
Discussion: https://postgr.es/m/ZbyVVG_7eW3YD5-A@paquier.xyz
Allow using multiple worker processes to build BRIN index, which until
now was supported only for BTREE indexes. For large tables this often
results in significant speedup when the build is CPU-bound.
The work is split in a simple way - each worker builds BRIN summaries on
a subset of the table, determined by the regular parallel scan used to
read the data, and feeds them into a shared tuplesort which sorts them
by blkno (start of the range). The leader then reads this sorted stream
of ranges, merges duplicates (which may happen if the parallel scan does
not align with BRIN pages_per_range), and adds the resulting ranges into
the index.
The number of duplicate results produced by workers (requiring merging
in the leader process) should be fairly small, thanks to how parallel
scans assign chunks to workers. The likelihood of duplicate results may
increase for higher pages_per_range values, but then there are fewer
page ranges in total. In any case, we expect the merging to be much
cheaper than summarization, so this should be a win.
Most of the parallelism infrastructure is a simplified copy of the code
used by BTREE indexes, omitting the parts irrelevant for BRIN indexes
(e.g. uniqueness checks).
This also introduces a new index AM flag amcanbuildparallel, determining
whether to attempt to start parallel workers for the index build.
Original patch by me, with reviews and substantial reworks by Matthias
van de Meent, certainly enough to make him a co-author.
Author: Tomas Vondra, Matthias van de Meent
Reviewed-by: Matthias van de Meent
Discussion: https://postgr.es/m/c2ee7d69-ce17-43f2-d1a0-9811edbda6e6%40enterprisedb.com
Commit 861f86beea changed hash_xlog_squeeze_page() to start reading
the write buffer conditionally but forgot to initialize it leading to an
uninitialized access.
Reported-by: Alexander Lakhin
Author: Hayato Kuroda
Reviewed-by: Alexander Lakhin, Amit Kapila
Discussion: http://postgr.es/m/62ed1a9f-746a-8e86-904b-51b9b806a1d9@gmail.com
The brininsert code used to initialize (and destroy) BrinDesc and
BrinRevmap for each tuple, which is not free. This patch initializes
these structures only once, and reuses them for all inserts in the same
command. The data is passed through indexInfo->ii_AmCache.
This also introduces an optional AM callback "aminsertcleanup" that
allows performing custom cleanup in case simply pfree-ing ii_AmCache is
not sufficient (which is the case when the cache contains TupleDesc,
Buffers, and so on).
Author: Soumyadeep Chakraborty
Reviewed-by: Alvaro Herrera, Matthias van de Meent, Tomas Vondra
Discussion: https://postgr.es/m/CAE-ML%2B9r2%3DaO1wwji1sBN9gvPz2xRAtFUGfnffpd0ZqyuzjamA%40mail.gmail.com
Commit 00d7fb5e2e started to use REGBUF_NO_CHANGE at a few places in the
code where we register the buffer before marking it dirty but missed
updating one of the code flows in the hash index where we free the overflow
page without any live tuples on it.
Author: Amit Kapila and Hayato Kuroda
Discussion: http://postgr.es/m/f045c8f7-ee24-ead6-3679-c04a43d21351@gmail.com
Enforce the rule from transam/README in XLogRegisterBuffer(), and
update callers to follow the rule.
Hash indexes sometimes register clean pages as a part of the locking
protocol, so provide a REGBUF_NO_CHANGE flag to support that use.
Discussion: https://postgr.es/m/c84114f8-c7f1-5b57-f85a-3adc31e1a904@iki.fi
Reviewed-by: Heikki Linnakangas
Commit 31966b15 invented a way for functions dealing with relation
extension to accept a Relation in online code and an SMgrRelation in
recovery code. It seems highly likely that future bufmgr.c interfaces
will face the same problem, and need to do something similar.
Generalize the names so that each interface doesn't have to re-invent
the wheel.
Back-patch to 16. Since extension AM authors might start using the
constructor macros once 16 ships, we agreed to do the rename in 16
rather than waiting for 17.
Reviewed-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA%2BhUKG%2B6tLD2BhpRWycEoti6LVLyQq457UL4ticP5xd8LqHySA%40mail.gmail.com
Run pgindent, pgperltidy, and reformat-dat-files.
This set of diffs is a bit larger than typical. We've updated to
pg_bsd_indent 2.1.2, which properly indents variable declarations that
have multi-line initialization expressions (the continuation lines are
now indented one tab stop). We've also updated to perltidy version
20230309 and changed some of its settings, which reduces its desire to
add whitespace to lines to make assignments etc. line up. Going
forward, that should make for fewer random-seeming changes to existing
code.
Discussion: https://postgr.es/m/20230428092545.qfb3y5wcu4cm75ur@alvherre.pgsql
During WAL replay on the standby, when a conflict with a logical slot is
identified, invalidate such slots. There are two sources of conflicts:
1) Using the information added in 6af1793954, logical slots are invalidated if
required rows are removed
2) wal_level on the primary server is reduced to below logical
Uses the infrastructure introduced in the prior commit. FIXME: add commit
reference.
Change InvalidatePossiblyObsoleteSlot() to use a recovery conflict to
interrupt use of a slot, if called in the startup process. The new recovery
conflict is added to pg_stat_database_conflicts, as confl_active_logicalslot.
See 6af1793954 for an overall design of logical decoding on a standby.
Bumps catversion for the addition of the pg_stat_database_conflicts column.
Bumps PGSTAT_FILE_FORMAT_ID for the same reason.
Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Author: Amit Khandekar <amitdkhan.pg@gmail.com> (in an older version)
Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/20230407075009.igg7be27ha2htkbt@awork3.anarazel.de
In order to have the option to use O_DIRECT/FILE_FLAG_NO_BUFFERING in a
later commit, we need the addresses of user space buffers to be well
aligned. The exact requirements vary by OS and file system (typically
sectors and/or memory pages). The address alignment size is set to
4096, which is enough for currently known systems: it matches modern
sectors and common memory page size. There is no standard governing
O_DIRECT's requirements so we might eventually have to reconsider this
with more information from the field or future systems.
Aligning I/O buffers on memory pages is also known to improve regular
buffered I/O performance.
Three classes of I/O buffers for regular data pages are adjusted:
(1) Heap buffers are now allocated with the new palloc_aligned() or
MemoryContextAllocAligned() functions introduced by commit 439f6175.
(2) Stack buffers now use a new struct PGIOAlignedBlock to respect
PG_IO_ALIGN_SIZE, if possible with this compiler. (3) The buffer
pool is also aligned in shared memory.
WAL buffers were already aligned on XLOG_BLCKSZ. It's possible for
XLOG_BLCKSZ to be configured smaller than PG_IO_ALIGNED_SIZE and thus
for O_DIRECT WAL writes to fail to be well aligned, but that's a
pre-existing condition and will be addressed by a later commit.
BufFiles are not yet addressed (there's no current plan to use O_DIRECT
for those, but they could potentially get some incidental speedup even
in plain buffered I/O operations through better alignment).
If we can't align stack objects suitably using the compiler extensions
we know about, we disable the use of O_DIRECT by setting PG_O_DIRECT to
0. This avoids the need to consider systems that have O_DIRECT but
can't align stack objects the way we want; such systems could in theory
be supported with more work but we don't currently know of any such
machines, so it's easier to pretend there is no O_DIRECT support
instead. That's an existing and tested class of system.
Add assertions that all buffers passed into smgrread(), smgrwrite() and
smgrextend() are correctly aligned, unless PG_O_DIRECT is 0 (= stack
alignment tricks may be unavailable) or the block size has been set too
small to allow arrays of buffers to be all aligned.
Author: Thomas Munro <thomas.munro@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/CA+hUKGK1X532hYqJ_MzFWt0n1zt8trz980D79WbjwnT-yYLZpg@mail.gmail.com
A few places are not converted. Some because they are tackled in later
commits (e.g. hio.c, xlogutils.c), some because they are more
complicated (e.g. brin_pageops.c). Having a few users of ReadBuffer(P_NEW) is
good anyway, to ensure the backward compat path stays working.
Discussion: https://postgr.es/m/20221029025420.eplyow6k7tgu6he3@awork3.anarazel.de
This commit only implements one prerequisite part for allowing logical
decoding. The commit message contains an explanation of the overall design,
which later commits will refer back to.
Overall design:
1. We want to enable logical decoding on standbys, but replay of WAL
from the primary might remove data that is needed by logical decoding,
causing error(s) on the standby. To prevent those errors, a new replication
conflict scenario needs to be addressed (as much as hot standby does).
2. Our chosen strategy for dealing with this type of replication slot
is to invalidate logical slots for which needed data has been removed.
3. To do this we need the latestRemovedXid for each change, just as we
do for physical replication conflicts, but we also need to know
whether any particular change was to data that logical replication
might access. That way, during WAL replay, we know when there is a risk of
conflict and, if so, if there is a conflict.
4. We can't rely on the standby's relcache entries for this purpose in
any way, because the startup process can't access catalog contents.
5. Therefore every WAL record that potentially removes data from the
index or heap must carry a flag indicating whether or not it is one
that might be accessed during logical decoding.
Why do we need this for logical decoding on standby?
First, let's forget about logical decoding on standby and recall that
on a primary database, any catalog rows that may be needed by a logical
decoding replication slot are not removed.
This is done thanks to the catalog_xmin associated with the logical
replication slot.
But, with logical decoding on standby, in the following cases:
- hot_standby_feedback is off
- hot_standby_feedback is on but there is no a physical slot between
the primary and the standby. Then, hot_standby_feedback will work,
but only while the connection is alive (for example a node restart
would break it)
Then, the primary may delete system catalog rows that could be needed
by the logical decoding on the standby (as it does not know about the
catalog_xmin on the standby).
So, it’s mandatory to identify those rows and invalidate the slots
that may need them if any. Identifying those rows is the purpose of
this commit.
Implementation:
When a WAL replay on standby indicates that a catalog table tuple is
to be deleted by an xid that is greater than a logical slot's
catalog_xmin, then that means the slot's catalog_xmin conflicts with
the xid, and we need to handle the conflict. While subsequent commits
will do the actual conflict handling, this commit adds a new field
isCatalogRel in such WAL records (and a new bit set in the
xl_heap_visible flags field), that is true for catalog tables, so as to
arrange for conflict handling.
The affected WAL records are the ones that already contain the
snapshotConflictHorizon field, namely:
- gistxlogDelete
- gistxlogPageReuse
- xl_hash_vacuum_one_page
- xl_heap_prune
- xl_heap_freeze_page
- xl_heap_visible
- xl_btree_reuse_page
- xl_btree_delete
- spgxlogVacuumRedirect
Due to this new field being added, xl_hash_vacuum_one_page and
gistxlogDelete do now contain the offsets to be deleted as a
FLEXIBLE_ARRAY_MEMBER. This is needed to ensure correct alignment.
It's not needed on the others struct where isCatalogRel has
been added.
This commit just introduces the WAL format changes mentioned above. Handling
the actual conflicts will follow in future commits.
Bumps XLOG_PAGE_MAGIC as the several WAL records are changed.
Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Author: Andres Freund <andres@anarazel.de> (in an older version)
Author: Amit Khandekar <amitdkhan.pg@gmail.com> (in an older version)
Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
When determining whether an index update may be skipped by using HOT, we
can ignore attributes indexed by block summarizing indexes without
references to individual tuples that need to be cleaned up.
A new type TU_UpdateIndexes provides a signal to the executor to
determine which indexes to update - no indexes, all indexes, or only the
summarizing indexes.
This also removes rd_indexattr list, and replaces it with rd_attrsvalid
flag. The list was not used anywhere, and a simple flag is sufficient.
This was originally committed as 5753d4ee32, but then got reverted by
e3fcca0d0d because of correctness issues.
Original patch by Josef Simanek, various fixes and improvements by Tomas
Vondra and me.
Authors: Matthias van de Meent, Josef Simanek, Tomas Vondra
Reviewed-by: Tomas Vondra, Alvaro Herrera
Discussion: https://postgr.es/m/05ebcb44-f383-86e3-4f31-0a97a55634cf@enterprisedb.com
Discussion: https://postgr.es/m/CAFp7QwpMRGcDAQumN7onN9HjrJ3u4X3ZRXdGFT0K5G2JWvnbWg%40mail.gmail.com
Offers a generally better separation of responsibilities for collation
code. Also, a step towards multi-lib ICU, which should be based on a
clean separation of the routines required for collation providers.
Callers with NUL-terminated strings should call pg_strcoll() or
pg_strxfrm(); callers with strings and their length should call the
variants pg_strncoll() or pg_strnxfrm().
Reviewed-by: Peter Eisentraut, Peter Geoghegan
Discussion: https://postgr.es/m/a581136455c940d7bd0ff482d3a2bd51af25a94f.camel%40j-davis.com
