Remove one of the arguments to btvacuumpage(), and give up on the idea
that it's a recursive function. We now use the term "backtracking" to
refer to the case where an earlier block must be visited to make sure no
tuples that need to be removed were missed.
Advertising btvacuumpage() as a recursive function was unhelpful. In
reality the function always simulates recursion with a loop (it doesn't
actually call itself). This wasn't just necessary as a precaution (per
the comments mentioning tail recursion), though. There is no reliable
natural limit on the number of times we can backtrack.
There are important behavioral difference when "recursing"/backtracking,
mostly related to page deletion. We don't perform page deletion when
backtracking due to the extra complexity. And when we recurse, we're
not performing a physical order scan anymore, so we expect fairly
different conditions to hold for the page. Structuring the code like
this makes it clearer how _bt_pagedel() cooperates with btvacuumpage()
and btvacuumscan() (as established in commit b0229f26 and commit
73a076b0).
Author: Peter Geoghegan
Reviewed-By: Masahiko Sawada
Discussion: https://postgr.es/m/CAH2-WzmRGMDWiLMcb+zagG9652PboNN4Gfcq1Gc_wJL6A716MA@mail.gmail.com
On further reflection, code comments added by commit b0229f26 slightly
misrepresented how we determine the oldest bpto.xact for the index.
btvacuumpage() does not treat the bpto.xact of a page that it put in the
FSM as a candidate to be the oldest deleted page (the delete-marked page
that has the oldest bpto.xact XID among all pages encountered).
The definition of a deleted page for the purposes of the bpto.xact
calculation is different from the definition used by the bulk delete
statistics. The bulk delete statistics don't distinguish between pages
that were deleted by the current VACUUM, pages deleted by a previous
VACUUM operation but not yet recyclable/reusable, and pages that are
reusable (though reusable pages are counted separately).
Backpatch: 11-, just like commit b0229f26.
The logic for determining how many nbtree pages in an index are deleted
pages sometimes undercounted pages. Pages that were deleted by the
current VACUUM operation (as opposed to some previous VACUUM operation
whose deleted pages have yet to be reused) were sometimes overlooked.
The final count is exposed to users through VACUUM VERBOSE's "%u index
pages have been deleted" output.
btvacuumpage() avoided double-counting when _bt_pagedel() deleted more
than one page by assuming that only one page was deleted, and that the
additional deleted pages would get picked up during a future call to
btvacuumpage() by the same VACUUM operation. _bt_pagedel() can
legitimately delete pages that the btvacuumscan() scan will not visit
again, though, so that assumption was slightly faulty.
Fix the accounting by teaching _bt_pagedel() about its caller's
requirements. It now only reports on pages that it knows btvacuumscan()
won't visit again (including the current btvacuumpage() page), so
everything works out in the end.
This bug has been around forever. Only backpatch to v11, though, to
keep _bt_pagedel() is sync on the branches that have today's bugfix
commit b0229f26da. Note that this commit changes the signature of
_bt_pagedel(), just like commit b0229f26da.
Author: Peter Geoghegan
Reviewed-By: Masahiko Sawada
Discussion: https://postgr.es/m/CAH2-WzkrXBcMQWAYUJMFTTvzx_r4q=pYSjDe07JnUXhe+OZnJA@mail.gmail.com
Backpatch: 11-
Commit 857f9c36cd (which taught nbtree VACUUM to skip a scan of the
index from btcleanup in situations where it doesn't seem worth it) made
VACUUM maintain the oldest btpo.xact among all deleted pages for the
index as a whole. It failed to handle all the details surrounding pages
that are deleted by the current VACUUM operation correctly (though pages
deleted by some previous VACUUM operation were processed correctly).
The most immediate problem was that the special area of the page was
examined without a buffer pin at one point. More fundamentally, the
handling failed to account for the full range of _bt_pagedel()
behaviors. For example, _bt_pagedel() sometimes deletes internal pages
in passing, as part of deleting an entire subtree with btvacuumpage()
caller's page as the leaf level page. The original leaf page passed to
_bt_pagedel() might not be the page that it deletes first in cases where
deletion can take place.
It's unclear how disruptive this bug may have been, or what symptoms
users might want to look out for. The issue was spotted during
unrelated code review.
To fix, push down the logic for maintaining the oldest btpo.xact to
_bt_pagedel(). btvacuumpage() is now responsible for pages that were
fully deleted by a previous VACUUM operation, while _bt_pagedel() is now
responsible for pages that were deleted by the current VACUUM operation
(this includes half-dead pages from a previous interrupted VACUUM
operation that become fully deleted in _bt_pagedel()). Note that
_bt_pagedel() should never encounter an existing deleted page.
This commit theoretically breaks the ABI of a stable release by changing
the signature of _bt_pagedel(). However, if any third party extension
is actually affected by this, then it must already be completely broken
(since there are numerous assumptions made in _bt_pagedel() that cannot
be met outside of VACUUM). It seems highly unlikely that such an
extension actually exists, in any case.
Author: Peter Geoghegan
Reviewed-By: Masahiko Sawada
Discussion: https://postgr.es/m/CAH2-WzkrXBcMQWAYUJMFTTvzx_r4q=pYSjDe07JnUXhe+OZnJA@mail.gmail.com
Backpatch: 11-, where the "skip full scan" feature was introduced.
Avoid accessing the leaf page's top parent tuple without a buffer lock
held during the second phase of nbtree page deletion. The old approach
was safe, though only because VACUUM never drops its buffer pin (and
because only VACUUM itself can modify a half-dead page). Even still, it
seems like a good idea to be strict here. Tighten things up by copying
the top parent page's block number to a local variable before releasing
the buffer lock on the leaf page -- not after.
This is a follow-up to commit fa7ff642, which fixed a similar issue in
the first phase of nbtree page deletion.
Update some related comments in passing.
Discussion: https://postgr.es/m/CAH2-WzkLgyN3zBvRZ1pkNJThC=xi_0gpWRUb_45eexLH1+k2_Q@mail.gmail.com
Avoid accessing the deletion target page's special area during nbtree
page deletion at a point where there is no buffer lock held. This issue
was detected by a patch that extends Valgrind's memcheck tool to mark
nbtree pages that are unsafe to access (due to not having a buffer lock
or buffer pin) as NOACCESS.
We do hold a buffer pin at this point, and only access the special area,
so the old approach was safe. Even still, it seems like a good idea to
tighten up the rules in this area. There is no reason to not simply
insist on always holding a buffer lock (not just a pin) when accessing
nbtree pages.
Update some related comments in passing.
Discussion: https://postgr.es/m/CAH2-WzkLgyN3zBvRZ1pkNJThC=xi_0gpWRUb_45eexLH1+k2_Q@mail.gmail.com
78ea8b5 has fixed an issue related to the recycling of WAL segments on
standbys depending on archive_mode. However, it has introduced a
regression with the handling of WAL segments ready to be archived during
crash recovery, causing those files to be recycled without getting
archived.
This commit fixes the regression by tracking in shared memory if a live
cluster is either in crash recovery or archive recovery as the handling
of WAL segments ready to be archived is different in both cases (those
WAL segments should not be removed during crash recovery), and by using
this new shared memory state to decide if a segment can be recycled or
not. Previously, it was not possible to know if a cluster was in crash
recovery or archive recovery as the shared state was able to track only
if recovery was happening or not, leading to the problem.
A set of TAP tests is added to close the gap here, making sure that WAL
segments ready to be archived are correctly handled when a cluster is in
archive or crash recovery with archive_mode set to "on" or "always", for
both standby and primary.
Reported-by: Benoît Lobréau
Author: Jehan-Guillaume de Rorthais
Reviewed-by: Kyotaro Horiguchi, Fujii Masao, Michael Paquier
Discussion: https://postgr.es/m/20200331172229.40ee00dc@firost
Backpatch-through: 9.5
index.c supposed that it could just use a PG_TRY block to clean up the
state associated with an active REINDEX operation. However, that code
doesn't run if we do a FATAL exit --- for example, due to a SIGTERM
shutdown signal --- while the REINDEX is happening. And that state does
get consulted during catalog accesses, which makes it problematic if we
do any catalog accesses during shutdown --- for example, to clean up any
temp tables created in the session.
If this combination of circumstances occurred, we could find ourselves
trying to access already-freed memory. In debug builds that'd fairly
reliably cause an assertion failure. In production we might often
get away with it, but with some bad luck it could cause a core dump.
Another possible bad outcome is an erroneous conclusion that an
index-to-be-accessed is being reindexed; but it looks like that would
be unlikely to have any consequences worse than failing to drop temp
tables right away. (They'd still get dropped by the next session that
uses that temp schema.)
To fix, get rid of the use of PG_TRY here, and instead hook into
the transaction abort mechanisms to clean up reindex state.
Per bug #16378 from Alexander Lakhin. This has been wrong for a
very long time, so back-patch to all supported branches.
Discussion: https://postgr.es/m/16378-7a70ca41b3ec2009@postgresql.org
Commit 0d861bbb, which introduced deduplication to nbtree, added some
logic to take large posting list tuples into account when choosing a
split point. We subtract firstright posting list overhead from the
projected new high key size when calculating leftfree/rightfree values
for an affected candidate split point. Posting list tuples aren't
special to nbtsplitloc.c, but taking them into account like this makes a
huge difference in practice. Posting list tuples are frequently tuple
size outliers.
However, commit 0d861bbb missed a closely related issue: split interval
itself is calculated based on the assumption that tuples on the page
being split are roughly equisized. That assumption was acceptable back
when commit fab25024 taught the logic for choosing a split point about
suffix truncation, but it's pretty questionable now that very large
tuple sizes are common. This oversight led to unbalanced page splits in
low cardinality multi-column indexes when deduplication was used: page
splits that don't give sufficient weight to how unbalanced the split is
when the interval happens to include some large posting list tuples (and
when most other tuples on the page are not so large).
Nail this down by calculating an initial split interval in a way that's
attuned to the actual cost that we want to keep under control (not a
fuzzy proxy for the cost): apply a leftfree + rightfree evenness test to
each candidate split point that actually gets included in the split
interval (for the default strategy). This replaces logic that used a
percentage of all legal split points for the page as the basis of the
initial split interval.
Discussion: https://postgr.es/m/CAH2-WznJt5aT2uUB2Bs+JBLdwe0XTX67+xeLFcaNvCKxO=QBVQ@mail.gmail.com
A comment from the Berkeley days incorrectly claimed that the page
management code cares about the contents of the hole in the center of
the page (at least in the case of the left half of an nbtree page
split). Commit 8fa30f906b added an addendum that stated that the
original comment was "probably obsolete". It's definitely obsolete,
though, so remove the original comment plus the addendum.
Nest the "update metapage as part of insert into root-like page" branch
inside the broader "insert into internal page" branch. This improves
readability.
Clearly it's not okay for nbtree to split a page that is the only page
on its level, and then find that it has to split the parent one level up
in turn. There is simply no code to handle the split_only_page case in
the _bt_insertonpg() "newitem won't fit" branch (only the "newitem fits"
branch handles split_only_page). Add a defensive assertion that will
fail if a split_only_page call to _bt_insertonpg() somehow ends up
splitting the target/parent page.
I (pgeoghegan) believe that we don't need split_only_page handling for
the "newitem won't fit" branch because anybody calling _bt_insertonpg()
like this would have to hold a lock on the same one and only child page.
It seems like a good idea for nbtree's retail insert code to be
absolutely consistent with nbtree's page split code for anything that
naturally requires equivalent handling. Anything that concerns
inserting newitem (which is handled as part of the page split atomic
action when a page split is required) should work in exactly the same
way. With that in mind, make _bt_insertonpg() handle 'cbuf' in a way
that matches _bt_split().
An nbtree split point can be thought of as a point between two adjoining
tuples from an imaginary version of the page being split that includes
the incoming/new item (in addition to the items that really are on the
page). These adjoining tuples are called the lastleft and firstright
tuples.
The variables that represent split points contained a field called
firstright, which is an offset number of the first data item from the
original page that goes on the new right page. The corresponding tuple
from origpage was usually the same thing as the actual firstright tuple,
but not always: the firstright tuple is sometimes the new/incoming item
instead. This situation seems unnecessarily confusing.
Make things clearer by renaming the origpage offset returned by
_bt_findsplitloc() to "firstrightoff". We now have a firstright tuple
and a firstrightoff offset number which are comparable to the
newitem/lastleft tuples and the newitemoff/lastleftoff offset numbers
respectively. Also make sure that we are consistent about how we
describe nbtree page split point state.
Push the responsibility for dealing with pg_upgrade'd !heapkeyspace
indexes down to lower level code, relieving _bt_split() from dealing
with it directly. This means that we always have a palloc'd left page
high key on the leaf level, no matter what. This enables simplifying
some of the code (and code comments) within _bt_split().
Finally, restructure the page split code to make it clearer why suffix
truncation (which only takes place during leaf page splits) is
completely different to the first data item truncation that takes place
during internal page splits. Tuples are marked as having fewer
attributes stored in both cases, and the firstright tuple is truncated
in both cases, so it's easy to imagine somebody missing the distinction.
Currently, we don't account for buffer usage incurred by parallel workers
for parallel create index. This commit allows each worker to record the
buffer usage stats and leader backend to accumulate that stats at the
end of the operation. This will allow pg_stat_statements to display
correct buffer usage stats for (parallel) create index command.
Reported-by: Julien Rouhaud
Author: Sawada Masahiko
Reviewed-by: Dilip Kumar, Julien Rouhaud and Amit Kapila
Backpatch-through: 11, where this was introduced
Discussion: https://postgr.es/m/20200328151721.GB12854@nol
GetWalRcvWriteRecPtr() previously reported the latest *flushed*
location. Adopt the conventional terminology used elsewhere in the tree
by renaming it to GetWalRcvFlushRecPtr(), and likewise for some related
variables that used the term "received".
Add a new definition of GetWalRcvWriteRecPtr(), which returns the latest
*written* value. This will allow later patches to use the value for
non-data-integrity purposes, without having to wait for the flush
pointer to advance.
Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA%2BhUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq%3DAovOddfHpA%40mail.gmail.com
0f5ca02f53 introduces 3 new keywords. It appears to be too much for relatively
small feature. Given now we past feature freeze, it's already late for
discussion of the new syntax. So, revert.
Discussion: https://postgr.es/m/28209.1586294824%40sss.pgh.pa.us
2nd pass of modifying various places which obtain the next power
of 2 of a number and make them use the new functions added in
f0705bb62.
In passing, also modify num_combinations(). This can be implemented
using simple bitshifting rather than looping.
Reviewed-by: John Naylor
Discussion: https://postgr.es/m/20200114173553.GE32763%40fetter.org
First pass of modifying various places that obtain the next power of 2 of
a number and make them use the new functions added in pg_bitutils.h
instead.
This also removes the _hash_log2() function. There are no longer any
callers in core. Other users can swap their _hash_log2(n) call to make use
of pg_ceil_log2_32(n).
Author: David Fetter, with some minor adjustments by me
Reviewed-by: John Naylor, Jesse Zhang
Discussion: https://postgr.es/m/20200114173553.GE32763%40fetter.org
The goal of separating hotly accessed per-backend data from PGPROC
into PGXACT is to make accesses fast (GetSnapshotData() in
particular). But delayChkpt is not actually accessed frequently; only
when starting a checkpoint. As it is frequently modified (multiple
times in the course of a single transaction), storing it in the same
cacheline as hotly accessed data unnecessarily dirties a contended
cacheline.
Therefore move delayChkpt to PGPROC.
This is part of a larger series of patches intending to improve
GetSnapshotData() scalability. It is committed and pushed separately,
as it is independently beneficial (small but measurable win, limited
by the other frequent modifications of PGXACT).
Author: Andres Freund
Reviewed-By: Robert Haas, Thomas Munro, David Rowley
Discussion: https://postgr.es/m/20200301083601.ews6hz5dduc3w2se@alap3.anarazel.de
SLRU page hits were tracked only in SimpleLruReadPage, but that's not
enough because we may hit the page in SimpleLruReadPage_ReadOnly in
which case we don't call SimpleLruReadPage at all.
Reported-by: Kuntal Ghosh
Discussion: https://postgr.es/m/20200119143707.gyinppnigokesjok@development
Before the fix every 2PC commit/abort leaked a file descriptor. As the
files are opened using BasicOpenFile(), that quickly leads to the
backend running out of file descriptors.
Once enough 2PC abort/commit have caused enough FDs to leak, any IO
in the backend will fail with "Too many open files", as
BasicOpenFilePerm() will have triggered all open files known to fd.c
to be closed.
The leak causing the problem at hand is a consequence of 0dc8ead46,
but is only exascerbated by it. Previously most XLogPageReadCB
callbacks used static variables to cache one open file, but after the
commit the cache is private to each XLogReader instance. There never
was infrastructure to close FDs at the time of XLogReaderFree, but the
way XLogReader was used limited the leak to one FD.
This commit just closes the during XLogReaderFree() if the FD is
stored in XLogReaderState.seg.ws_segno. This may not be the way to
solve this medium/long term, but at least unbreaks 2PC.
Discussion: https://postgr.es/m/20200406025651.fpzdb5yyb7qyhqko@alap3.anarazel.de
Since heap TID is supposed to be just another key attribute to the
implementation, it doesn't make much sense to have separate
BTreeTupleSetNAtts() and BTreeTupleSetAltHeapTID() functions. Merge the
two functions together. This slightly simplifies _bt_truncate().
Replication slots are useful to retain data that may be needed by a
replication system. But experience has shown that allowing them to
retain excessive data can lead to the primary failing because of running
out of space. This new feature allows the user to configure a maximum
amount of space to be reserved using the new option
max_slot_wal_keep_size. Slots that overrun that space are invalidated
at checkpoint time, enabling the storage to be released.
Author: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Jehan-Guillaume de Rorthais <jgdr@dalibo.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/20170228.122736.123383594.horiguchi.kyotaro@lab.ntt.co.jp
This commit adds following optional clause to BEGIN and START TRANSACTION
commands.
WAIT FOR LSN lsn [ TIMEOUT timeout ]
New clause pospones transaction start till given lsn is applied on standby.
This clause allows user be sure, that changes previously made on primary would
be visible on standby.
New shared memory struct is used to track awaited lsn per backend. Recovery
process wakes up backend once required lsn is applied.
Author: Ivan Kartyshov, Anna Akenteva
Reviewed-by: Craig Ringer, Thomas Munro, Robert Haas, Kyotaro Horiguchi
Reviewed-by: Masahiko Sawada, Ants Aasma, Dmitry Ivanov, Simon Riggs
Reviewed-by: Amit Kapila, Alexander Korotkov
Discussion: https://postgr.es/m/0240c26c-9f84-30ea-fca9-93ab2df5f305%40postgrespro.ru
Previously when there were multiple timelines listed in the history file
of the recovery target timeline, archive recovery searched all of them,
starting from the newest timeline to the oldest one, to find the segment
to read. That is, archive recovery had to continuously fail scanning
the segment until it reached the timeline that the segment belonged to.
These scans for non-existent segment could be harmful on the recovery
performance especially when archival area was located on the remote
storage and each scan could take a long time.
To address the issue, this commit changes archive recovery so that
it skips scanning the timeline that the segment to read doesn't belong to.
Author: Kyotaro Horiguchi, tweaked a bit by Fujii Masao
Reviewed-by: David Steele, Pavel Suderevsky, Grigory Smolkin
Discussion: https://postgr.es/m/16159-f5a34a3a04dc67e0@postgresql.org
Discussion: https://postgr.es/m/20200129.120222.1476610231001551715.horikyota.ntt@gmail.com
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
An assertion added by commit 0d861bbb checked that _bt_killitems() only
processes a BTScanPosItem whose heap TID is contained in a posting list
tuple when its page offset number still matches what is on the page
(i.e. when it matches the posting list tuple's current offset number).
This was only correct in the common case where the page can't have
changed since we first read it. It was not correct in cases where we
don't drop the buffer pin (and don't need to verify the page hasn't
changed using its LSN). The latter category includes scans involving
unlogged tables, and scans that use a non-MVCC snapshot, per the logic
originally introduced by commit 2ed5b87f.
The assertion still seems helpful. Fix it by taking cases where the
page may have been concurrently modified into account.
Reported-By: Anastasia Lubennikova, Alexander Lakhin
Discussion: https://postgr.es/m/c4e38e9a-0f9c-8e53-e639-adf343f94472@postgrespro.ru
There's a very low risk that RecentGlobalXmin could be far enough in
the past to be older than relfrozenxid, or even wrapped
around. Luckily the consequences of that having happened wouldn't be
too bad - the page wouldn't be pruned for a while.
Avoid that risk by using TransactionXmin instead. As that's announced
via MyPgXact->xmin, it is protected against wrapping around (see code
comments for details around relfrozenxid).
Author: Andres Freund
Discussion: https://postgr.es/m/20200328213023.s4eyijhdosuc4vcj@alap3.anarazel.de
Backpatch: 9.5-
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
This allows gathering the WAL generation statistics for each statement
execution. The three statistics that we collect are the number of WAL
records, the number of full page writes and the amount of WAL bytes
generated.
This helps the users who have write-intensive workload to see the impact
of I/O due to WAL. This further enables us to see approximately what
percentage of overall WAL is due to full page writes.
In the future, we can extend this functionality to allow us to compute the
the exact amount of WAL data due to full page writes.
This patch in itself is just an infrastructure to compute WAL usage data.
The upcoming patches will expose this data via explain, auto_explain,
pg_stat_statements and verbose (auto)vacuum output.
Author: Kirill Bychik, Julien Rouhaud
Reviewed-by: Dilip Kumar, Fujii Masao and Amit Kapila
Discussion: https://postgr.es/m/CAB-hujrP8ZfUkvL5OYETipQwA=e3n7oqHFU=4ZLxWS_Cza3kQQ@mail.gmail.com
A manifest is a JSON document which includes (1) the file name, size,
last modification time, and an optional checksum for each file backed
up, (2) timelines and LSNs for whatever WAL will need to be replayed
to make the backup consistent, and (3) a checksum for the manifest
itself. By default, we use CRC-32C when checksumming data files,
because we are trying to detect corruption and user error, not foil an
adversary. However, pg_basebackup and the server-side BASE_BACKUP
command now have options to select a different algorithm, so users
wanting a cryptographic hash function can select SHA-224, SHA-256,
SHA-384, or SHA-512. Users not wanting file checksums at all can
disable them, or disable generating of the backup manifest altogether.
Using a cryptographic hash function in place of CRC-32C consumes
significantly more CPU cycles, which may slow down backups in some
cases.
A new tool called pg_validatebackup can validate a backup against the
manifest. If no checksums are present, it can still check that the
right files exist and that they have the expected sizes. If checksums
are present, it can also verify that each file has the expected
checksum. Additionally, it calls pg_waldump to verify that the
expected WAL files are present and parseable. Only plain format
backups can be validated directly, but tar format backups can be
validated after extracting them.
Robert Haas, with help, ideas, review, and testing from David Steele,
Stephen Frost, Andrew Dunstan, Rushabh Lathia, Suraj Kharage, Tushar
Ahuja, Rajkumar Raghuwanshi, Mark Dilger, Davinder Singh, Jeevan
Chalke, Amit Kapila, Andres Freund, and Noah Misch.
Discussion: http://postgr.es/m/CA+TgmoZV8dw1H2bzZ9xkKwdrk8+XYa+DC9H=F7heO2zna5T6qg@mail.gmail.com
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
Commit 40d964ec99 allowed vacuum command to process indexes in parallel but
forgot to accumulate the buffer usage stats of parallel workers. This
allows leader backend to accumulate buffer usage stats of all the parallel
workers.
Reported-by: Julien Rouhaud
Author: Sawada Masahiko
Reviewed-by: Dilip Kumar, Amit Kapila and Julien Rouhaud
Discussion: https://postgr.es/m/20200328151721.GB12854@nol
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
When recovery target is reached and recovery is paused because of
recovery_target_action=pause, executing pg_wal_replay_resume() causes
the standby to promote, i.e., the recovery to end. So, in this case,
the previous message "Execute pg_wal_replay_resume() to continue"
logged was confusing because pg_wal_replay_resume() doesn't cause
the recovery to continue.
This commit improves the message logged when recovery is paused,
and the proper message is output based on what (pg_wal_replay_pause
or recovery_target_action) causes recovery to be paused.
Author: Sergei Kornilov, revised by Fujii Masao
Reviewed-by: Robert Haas
Discussion: https://postgr.es/m/19168211580382043@myt5-b646bde4b8f3.qloud-c.yandex.net
The definitions of the routines defined in xlogarchive.c have been part
of xlog_internal.h which is included by several frontend tools, but all
those routines are only called by the backend. More cleanup could be
done within xlog_internal.h, but that's already a nice cut.
This will help a follow-up patch for pg_rewind where handling of
restore_command is added for frontends.
Author: Alexey Kondratov, Michael Paquier
Reviewed-by: Álvaro Herrera, Alexander Korotkov
Discussion: https://postgr.es/m/a3acff50-5a0d-9a2c-b3b2-ee36168955c1@postgrespro.ru
vacuum code.
After commit b61d161c14, during vacuum, we cache the information of
relation name and relation namespace in local structure LVRelStats so that
we can use it in an error callback function. We can use the cached
information to avoid the calls to RelationGetRelationName(),
RelationGetNamespace() and get_namespace_name(). This is mainly for the
consistent in vacuum code path but it will avoid the extra syscache lookup
we do in get_namespace_name().
Author: Justin Pryzby
Reviewed-by: Amit Kapila
Discussion: https://www.postgresql.org/message-id/20191120210600.GC30362@telsasoft.com
Peter Geoghegan
Michael Paquier
Peter Eisentraut
Tom Lane
Amit Kapila
Thomas Munro
Alexander Korotkov
David Rowley
Andres Freund
Tomas Vondra
Alvaro Herrera
Fujii Masao
Noah Misch
Robert Haas