Commit Graph

233 Commits (7e0dc18b22b71b16a3b418d7c2c2d86d65bff8a2)

Author SHA1 Message Date
sminux 5708fca1ea fix bad copy-paste rightComparisonLimit (#7547)
DESCRIPTION: change for #7543
(cherry picked from commit d59c93bc50)
2024-04-17 10:26:50 +02:00
Jelte Fennema-Nio 48c62095ff Actually sort includes after cherry-pick 2024-04-17 10:26:50 +02:00
Nils Dijk 75df19b616 move pg_version_constants.h to toplevel include (#7335)
In preparation of sorting and grouping all includes we wanted to move
this file to the toplevel includes for good grouping/sorting.

(cherry picked from commit 0dac63afc0)
2024-04-17 10:26:50 +02:00
Naisila Puka 7c6b4ce103
PG16 compatibility - outer join checks, subscription password, crash fixes (#7097)
PG16 compatibility - Part 4

Check out part 1 42d956888d
part 2 0d503dd5ac
part 3 907d72e60d

This commit is in the series of PG16 compatibility commits.
It adds some outer join checks to the planner,
the new password_required option to the subscription,
and a crash fix related to PGIOAlignedBlock, see below for more details:

- Fix PGIOAlignedBlock Assert crash in PG16 
Relevant PG commit:
faeedbcefd
faeedbcefd40bfdf314e048c425b6d9208896d90

- Pass planner info as argument to make_simple_restrictinfo 
Pre PG16 passing plannerInfo to make_simple_restrictinfo
was only needed for placeholder Vars, which is not the case
in this part of the codebase because we are building the
expression from shard intervals which don't have placeholder
vars.
However, PG16 is counting baserels appearing in clause_relids
and is deleting the rels mentioned in plannerinfo->outer_join_rels
Hence directly accessing plannerinfo.
We will crash if we leave it as NULL.
For reference
2489d76c49 (diff-e045c41eda9686451a7993e91518e40056b3739365e39eb1b70ae438dc1f7c76R207)
Relevant PG commit:
2489d76c49
2489d76c4906f4461a364ca8ad7e0751ead8aa0d

- Add outer join checks, root->simple_rel_array

- fix rebalancer to include passwork_required option 
Relevant PG commit:
c3afe8cf5a
c3afe8cf5a1e465bd71e48e4bc717f5bfdc7a7d6

More PG16 compatibility commits are coming soon ...
2023-08-04 14:51:28 +03:00
Naisila Puka 42d956888d
PG16 compatibility: Resolve compilation issues (#7005)
This PR provides successful compilation against PG16Beta2. It does some
necessary refactoring to prepare for full support of version 16, in
https://github.com/citusdata/citus/pull/6952 .

Change RelFileNode to RelFileNumber or RelFileLocator 
Relevant PG commit
b0a55e43299c4ea2a9a8c757f9c26352407d0ccc

new header for varatt.h 
Relevant PG commit:
d952373a987bad331c0e499463159dd142ced1ef

drop support for Abs, use fabs 
Relevant PG commit
357cfefb09115292cfb98d504199e6df8201c957

tuplesort PGcommit: d37aa3d35832afde94e100c4d2a9618b3eb76472 
Relevant PG commit:
d37aa3d35832afde94e100c4d2a9618b3eb76472

Fix vacuum in columnar 
Relevant PG commit:
4ce3afb82ecfbf64d4f6247e725004e1da30f47c
older one:
b6074846cebc33d752f1d9a66e5a9932f21ad177

Add alloc_flags to pg_clean_ascii 
Relevant PG commit:
45b1a67a0fcb3f1588df596431871de4c93cb76f

Merge GetNumConfigOptions() into get_guc_variables() 
Relevant PG commit:
3057465acfbea2f3dd7a914a1478064022c6eecd

Minor PG refactor PG_FUNCNAME_MACRO __func__ 
Relevant PG commit
320f92b744b44f961e5d56f5f21de003e8027a7f

Pass NULL context to stringToQualifiedNameList, typeStringToTypeName 
The pre-PG16 error behaviour for the following
stringToQualifiedNameList & typeStringToTypeName
was ereport(ERROR, ...)
Now with PG16 we have this context input. We preserve the same behaviour
by passing a NULL context, because of the following:
(copy paste comment from PG16)
If "context" isn't an ErrorSaveContext node, this behaves as
errstart(ERROR, domain), and the errsave() macro ends up acting
exactly like ereport(ERROR, ...).
Relevant PG commit
858e776c84f48841e7e16fba7b690b76e54f3675

Use RangeVarCallbackMaintainsTable instead of RangeVarCallbackOwnsTable 
Relevant PG commit:
60684dd834a222fefedd49b19d1f0a6189c1632e

FIX THIS: Not implemented grant-level control of role inheritance 
see PG commit
e3ce2de09d814f8770b2e3b3c152b7671bcdb83f

Make Scan node abstract 
PG commit:
8c73c11a0d39049de2c1f400d8765a0eb21f5228

Change in Var representations, get_relids_in_jointree 
PG commit
2489d76c4906f4461a364ca8ad7e0751ead8aa0d

Deadlock detection changes because SHM_QUEUE is removed 
Relevant PG Commit:
d137cb52cb7fd44a3f24f3c750fbf7924a4e9532

TU_UpdateIndexes 
Relevant PG commit
19d8e2308bc51ec4ab993ce90077342c915dd116

Use object_ownercheck and object_aclcheck functions 
Relevant PG commits:
afbfc02983f86c4d71825efa6befd547fe81a926
c727f511bd7bf3c58063737bcf7a8f331346f253

Rework Permission Info for successful compilation 
Relevant PG commits:
postgres/postgres@a61b1f7
postgres/postgres@b803b7d
---------

Co-authored-by: onderkalaci <onderkalaci@gmail.com>
2023-07-21 14:32:37 +03:00
Naisila Puka a282953274
Fix ScanKeyInit RegProcedure and Datum arguments (#7072)
Index scans in PG16 return empty sets because of extra compatibility
enforcement for `ScanKeyInit` arguments.
Could be one of the relevant PG commits:
c8b2ef05f4
This PR fixes all incompatible `RegProcedure` and `Datum` arguments in
all `ScanKeyInit` functions used throughout the codebase.
Helpful for https://github.com/citusdata/citus/pull/6952
2023-07-21 14:11:10 +03:00
Naisila Puka 69af3e8509
Drop PG13 Support Phase 2 - Remove PG13 specific paths/tests (#7007)
This commit is the second and last phase of dropping PG13 support.

It consists of the following:

- Removes all PG_VERSION_13 & PG_VERSION_14 from codepaths
- Removes pg_version_compat entries and columnar_version_compat entries
specific for PG13
- Removes alternative pg13 test outputs 
- Removes PG13 normalize lines and fix the test outputs based on that

It is a continuation of 5bf163a27d
2023-06-21 14:18:23 +03:00
Naisila Puka ba40eb363c
Fix some gucs' initial and boot values, and flag combinations (#6957)
PG16beta1 added some sanity checks for GUCS, find the Relevant PG
commits below:

1- Add check on initial and boot values when loading GUCs

a73952b795
2- Extend check_GUC_init() with checks on flag combinations when loading
GUCs

009f8d1714

I fixed our currently problematic GUCS, we can merge this directly into
main as these make sense for any PG version.

There was a particular NodeConninfo issue:
Previously we would rely on the fact that NodeConninfo initial value
is an empty string. However, with PG16 enforcing same initial and boot
values, we can't use an empty initial value for NodeConninfo anymore.
Therefore we add a new flag to indicate whether we are at boot check.
2023-06-14 11:55:52 +03:00
Naisila Puka 2ba3bffe1e
Random warning fixes (#6974)
Citus build with PG16 fails because of the following warnings:
 - using char* instead of Datum
 - using pointer instead of oid
 - candidate function for format attribute
 - remove old definition from PG11 compatibility 62bf571ced

This commit fixes the above.
2023-06-09 14:36:43 +03:00
Hanefi Onaldi efd41e8ea5
Bump columnar to 11.3 (#6898)
When working on changelog, Marco suggested in
https://github.com/citusdata/citus/pull/6856#pullrequestreview-1386601215
that we should bump columnar version to 11.3 as well.

This PR aims to contain all the necessary changes to allow upgrades to
and downgrades from 11.3.0 for columnar. Note that updating citus
extension version does not affect columnar as the two extension versions
are not really coupled.

The same changes will also be applied to the release branch in
https://github.com/citusdata/citus/pull/6897
2023-05-02 11:58:32 +03:00
Onur Tirtir 9550ebd118 Remove pg_depend entries from columnar metadata indexes to columnar-am
In the past, having columnar tables in the cluster was causing pg
upgrades to fail when attempting to access columnar metadata. This is
because, pg_dump doesn't see objects that we use for columnar-am related
booking as the dependencies of the tables using columnar-am.
To fix that; in #5456, we inserted some "normal dependency" edges (from
those objects to columnar-am) into pg_depend.

This helped us ensuring the existency of a class of metadata objects
--such as columnar.storageid_seq-- and helped fixing #5437.

However, the normal-dependency edges that we added for indexes on
columnar metadata tables --such columnar.stripe_pkey-- didn't help at
all because they were indeed causing dependency loops (#5510) and
pg_dump was not able to take those dependency edges into the account.

For this reason, this commit deletes those dependency edges so that
pg_dump stops complaining about them. Note that it's not critical to
delete those edges from pg_depend since they're not breaking pg upgrades
but were triggering some warning messages. And given that backporting
a sql change into older versions is hard a lot, we skip backporting
this.
2023-03-14 17:13:52 +03:00
Onur Tirtir be0735a329 Use "cpp" to expand "#include" directives in columnar sql files 2023-03-14 17:13:52 +03:00
Onur Tirtir 1c51ddae49 Fall-back to seq-scan when accessing columnar metadata if the index doesn't exist
Fixes #6570.

In the past, having columnar tables in the cluster was causing pg
upgrades to fail when attempting to access columnar metadata. This is
because, pg_dump doesn't see objects that we use for columnar-am related
booking as the dependencies of the tables using columnar-am.
To fix that; in #5456, we inserted some "normal dependency" edges (from
those objects to columnar-am) into pg_depend.

This helped us ensuring the existency of a class of metadata objects
--such as columnar.storageid_seq-- and helped fixing #5437.

However, the normal-dependency edges that we added for indexes on
columnar metadata tables --such columnar.stripe_pkey-- didn't help at
all because they were indeed causing dependency loops (#5510) and
pg_dump was not able to take those dependency edges into the account.

For this reason, instead of inserting such dependency edges from indexes
to columnar-am, we allow columnar metadata accessors to fall-back to
sequential scan during pg upgrades.
2023-01-30 15:58:34 +03:00
Onur Tirtir d2d507eb85
Fix columnar README.md (#6633)
Reported in #6626.
2023-01-26 10:39:39 +03:00
Fabrízio de Royes Mello 37f3dff1ca
Simplify columnar perf example (#6526)
Rewrite the plpython function to generate random words in SQL to
simplify the usage and run the example.
2022-12-01 20:05:40 +01:00
Onur Tirtir 0b81f68def
Use memcpy instead of memcpy_s to avoid pointless limits in columnar (#6419)
DESCRIPTION: Raises memory limits in columnar from 256MB to 1GB for
reads and writes

This doesn't completely fix #5918 but at least increases the
buffer limits that might cause throwing an error when reading
from or writing into into columnar storage. A way better approach
to fix this is documented in #6420.

Replacing memcpy_s with memcpy is quite safe in those places
since we anyway make sure to allocate enough amount of memory
before writing into related buffers.
2022-10-11 14:57:31 +03:00
Ying Xu f21cbe68f8
[Columnar] Bugfix for Columnar: options ignored during ALTER TABLE rewrite (#6337)
DESCRIPTION: Fixes a bug that prevents retaining columnar table options after a table-rewrite
A fix for this issue: Columnar: options ignored during ALTER TABLE
rewrite #5927
The OID for the temporary table created during ALTER TABLE was not the
same as the original table's OID so the columnar options were not being
applied during rewrite.

The change is that I applied the original table's columnar options to
the new table so that it has the correct options during write. I also
added a test.
2022-10-05 11:42:09 -07:00
Hanefi Onaldi 11a9a3771f
Ensure no dependencies to index before drop 2022-10-04 18:56:20 +03:00
Ahmet Gedemenli d0fa10a98c
Bump Citus to 11.2devel (#6385) 2022-09-30 14:47:42 +03:00
Naisila Puka 98dcbeb304
Specifies that our CustomScan providers support projections (#6244)
Before, this was the default mode for CustomScan providers.
Now, the default is to assume that they can't project.
This causes performance penalties due to adding unnecessary
Result nodes.

Hence we use the newly added flag, CUSTOMPATH_SUPPORT_PROJECTION
to get it back to how it was.

In PG15 support branch we created explain functions to ignore
the new Result nodes, so we undo that in this commit.

Relevant PG commit:
955b3e0f9269639fb916cee3dea37aee50b82df0
2022-08-31 10:48:01 +03:00
Hanefi Onaldi a58523f1d8
Remove all references to .source files 2022-08-09 14:15:52 +03:00
Onder Kalaci 149771792b Remove useless version compats
most likely leftover from earlier versions
2022-07-29 10:31:55 +02:00
Ying Xu 7c1a93b26b
Removed USE_PGXS snippet in Makefile that was blocking citus build when flag is set (#6101)
Code snippet in Makefile was blocking Citus build when USE_PGXS flag was set. This was included for port to FSPG but is not needed for Citus engine and can be safely removed.
2022-07-28 14:15:45 -07:00
Ying Xu fdf090758b
Bugfix for IN clause to be considered during planner phase in Columnar (#6030)
Reported bug #5803 shows that we are currently not sending the IN clause to our planner for columnar. This PR fixes it by checking for ScalarArrayOpExpr in ExtractPushdownClause so that we do not skip it. Also added a test case for this new addition.
2022-07-27 11:06:49 -07:00
Naisila Puka 7d6410c838
Drop postgres 12 support (#6040)
* Remove if conditions with PG_VERSION_NUM < 13

* Remove server_above_twelve(&eleven) checks from tests

* Fix tests

* Remove pg12 and pg11 alternative test output files

* Remove pg12 specific normalization rules

* Some more if conditions in the code

* Change RemoteCollationIdExpression and some pg12/pg13 comments

* Remove some more normalization rules
2022-07-20 17:49:36 +03:00
ywj 1675519f93
Support citus_columnar as separate extension (#5911)
* Support upgrade and downgrade and separate columnar as citus_columnar extension

Co-authored-by: Yanwen Jin <yanwjin@microsoft.com>
Co-authored-by: Jeff Davis <jeff@j-davis.com>
2022-07-13 21:08:29 -07:00
aykutbozkurt da089d72c5 we should check if relation is valid after fetching a relation 2022-07-06 16:35:01 +03:00
Onder Kalaci bab4c0a8c3 Fixes a bug that prevents upgrades when there are no worker nodes 2022-06-28 15:54:49 +02:00
jeff-davis 74ce210f8b
Columnar: fix wraparound bug. (#5962)
columnar_vacuum_rel() now advances relfrozenxid.

Fixes #5958.
2022-05-25 07:50:48 -07:00
jeff-davis a2f5b068e6
Columnar: tighten security and improve visibility. (#5922)
Move internal storage details to a separate schema with no public
access to limit the possibility for information leakage.

Create views with public access that show storage details for those
columnar tables where the user has ownership privileges. Include
mapping between relation ID and storage ID for easier interpretation.
2022-05-20 15:30:31 -07:00
jeff-davis a9f8a60007
Columnar: support relation options with ALTER TABLE. (#5935)
Columnar: support relation options with ALTER TABLE.

Use ALTER TABLE ... SET/RESET to specify relation options rather than
alter_columnar_table_set() and alter_columnar_table_reset().

Not only is this more ergonomic, but it also allows better integration
because it can be treated like DDL on a regular table. For instance,
citus can use its own ProcessUtility_hook to distribute the new
settings to the shards.

DESCRIPTION: Columnar: support relation options with ALTER TABLE.
2022-05-20 08:35:00 -07:00
Jeff Davis 9915fe8a1a PG15: Handle different ways to get publication actions.
Account for PG commit 52e4f0cd47.
2022-05-02 10:12:03 -07:00
Jeff Davis 1c1ef7ab8d PG15: Handle extra argument to RelationCreateStorage.
Account for PG commit 9c08aea6a309. Introduce
RelationCreateStorage_compat.
2022-05-02 10:12:03 -07:00
Jeff Davis ac952b2cc2 PG15: Handle extra argument to ExecARDeleteTriggers.
Account for PG commit ba9a7e3921. Introduce
ExecARDeleteTriggers_compat.
2022-05-02 10:12:03 -07:00
Jeff Davis f944722c6a PG15: Use RelationGetSmgr() instead of RelationOpenSmgr().
Handle PG commit f10f0ae420.
2022-05-02 10:12:03 -07:00
jeff-davis c485a04139
Separate build of citus.so and citus_columnar.so. (#5805)
* Separate build of citus.so and citus_columnar.so.

Because columnar code is statically-linked to both modules, it doesn't
make sense to load them both at once.

A subsequent commit will make the modules entirely separate and allow
loading them both simultaneously.

Author: Yanwen Jin

* Separate citus and citus_columnar modules.

Now the modules are independent. Columnar can be loaded by itself, or
along with citus.

Co-authored-by: Jeff Davis <jefdavi@microsoft.com>
2022-03-31 19:47:17 -07:00
Marco Slot dcfbb51b6b Revert "Build Columnar.so and make Citus depends on it (#5661)"
This reverts commit a4133c69e8.
2022-03-02 11:33:15 +01:00
ywj a4133c69e8
Build Columnar.so and make Citus depends on it (#5661)
* [Columnar] Build columnar.so and let citus depends on it


Co-authored-by: Yanwen Jin <yanwjin@microsoft.com>
Co-authored-by: Ying Xu <32597660+yxu2162@users.noreply.github.com>
Co-authored-by: jeff-davis <Jeffrey.Davis@microsoft.com>
2022-03-01 23:31:14 +03:00
yxu2162 8974b2de66 Copied CheckCitusVersion over to Columnar to handle dependency issue. If we split columnar into two extensions, this will later be changed tl CheckColumnarVersion. 2022-02-18 09:47:39 -08:00
Ying Xu b5c116449b
Removed dependency from EnsureTableOwner (#5676)
Removed dependency for EnsureTableOwner. Also removed pg_fini() and columnar_tableam_finish() Still need to remove CheckCitusVersion dependency to make Columnar_tableam.h dependency free from Citus.
2022-02-04 12:45:07 -08:00
jeff-davis b072b9235e
Columnar: fix checksums, broken in a4067913. (#5669)
Checksums must be set directly before writing the page. log_newpage()
sets the page LSN, and therefore invalidates the checksum.
2022-02-02 13:22:11 -08:00
Heikki Linnakangas a40679139b
Use smgrextend() when extending relation, and WAL-log first. (#5654)
When creating a new table, we bypass the buffer cache and write the
initial pages directly with smgrwrite(). However, you're supposed to
use smgrextend() when extending a relation, rather than smgrwrite().
There isn't much difference between them, but smgrextend() updates the
relation size cache, which seems important, although I haven't seen
any real bugs caused by that.

Also, write the block to disk only after WAL-logging it, so that we
can include the LSN of the WAL record in the version that we write
out. Currently, the page as written to disk has LSN 0. That doesn't
cause any user-visible issues either, at worst it could make us
WAL-log a full page image of the page earlier than necessary, but that
doesn't matter currently because we WAL-log full page images of all
changes anyway.

I bumped into that issue with LSN 0 in the page header when testing
Citus with Zenith (https://github.com/zenithdb/zenith/issues/1176).
Zenith contains a check that PANICs if you write a block to disk
without WAL-logging it, and it works by checking the LSN of the page
that's written out. In this case, we are WAL-logging the page even
though the LSN on the page is 0, so it was a false alarm, but I'd love
to get this changed in Citus to keep the check in Zenith simple.

A downside of WAL-logging the page first is that if you run out of
disk space, you have already created the WAL record. So if you then
crash and restart, WAL recovery will likely run out of disk space,
too, which is bad. In practice, we have the same problem in other
places, like rewriteheap.c. Also, if you are on the brink of running
out of disk space, you will probably run out at WAL replay anyway,
regardless of which order we write these few pages. But if we wanted
to fix that, we could first extend the relation with zeros, and then
WAL-log the pages. That's how heap extension works.

It would be even nicer to use the buffer cache for this, and skip the
smgrimmedsync() on the relation. However, that would require more
work, because we don't have the Relation struct for the relation here.
We could use ReadBufferWithoutRelcache(), but that doesn't work for
unlogged tables. Unlogged tables are currently not supported
(https://github.com/citusdata/citus/issues/4742), but that would
become a problem if we want to support them in the future.
CreateFakeRelcacheEntry() also doesn't work with unlogged tables. We
could do things differently for logged and unlogged tables, but that
complicates the code further.

Co-authored-by: jeff-davis <Jeffrey.Davis@microsoft.com>
2022-01-27 12:04:08 -08:00
Ying Xu 4dca662e97
Making Columnar Dependency Free from Citus (#5622)
* Removed distributed dependency in columnar_metadata.c

* Changed columnar_debug.c so that it no longer needed distributed/tuplestore and made it return a record instead of a tuplestore

* removed distributed/commands.h dependency

* Made columnar_tableam.c dependency-free

* Fixed spacing for columnar_store_memory_stats function

* indentation fix

* fixed test failures
2022-01-14 09:43:05 -08:00
jeff-davis 2e03efd91e
Columnar: move DDL hooks to citus to remove dependency. (#5547)
Add a new hook ColumnarTableSetOptions_hook so that citus can get
control when the columnar table options change.
2022-01-04 23:26:46 -08:00
jeff-davis c9292cfad1
Make pg_version_compat.h and listutils.c dependency-free. (#5548)
Split distributed/version_compat.h into dependency-free
pg_version_compat.h, and the original which still has
dependencies. The original doesn't have much purpose, but until other
files have better discipline about including the correct header files,
then it's still needed.

Also make distributed/listutils.h dependency-free. Should be moved
outside of 'distributed' subdirectory, but that will cause significant
code churn, so leave for another cleanup patch.

Now both files can be included in columnar without creating a
dependency on citus.
2022-01-04 23:02:08 -08:00
jeff-davis 1546aa0d9f
Columnar: use proper generic WAL interface. (#5543)
Previously, we cheated by using the RM_GENERIC_ID record type, but not
actually using the generic WAL API. This worked because we always took
a full page image, and saved the extra work of allocating and copying
to a temporary page.

But it introduced complexity, and perhaps fragility, so better to just
use the API properly. The performance penalty for a serial data load
seems to be less than 1%.
2022-01-04 22:42:21 -08:00
Hanefi Onaldi 76176caea7 Fix typo s/exlusive/exclusive/ 2021-12-23 01:35:01 +03:00
Onur Tirtir cc4c83b1e5
HAVE_LZ4 -> HAVE_CITUS_LZ4 (#5541) 2021-12-16 16:21:52 +03:00
Hanefi Onaldi 13fff9c37a Remove NOOP tuplestore_donestoring calls
PostgreSQL does not need calling this function since 7.4 release, and it
is a NOOP.

For more details, check PostgreSQL commit below :

commit dd04e958c8b03c0f0512497651678c7816af3198
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date:   Sun Mar 9 03:34:10 2003 +0000

    tuplestore_donestoring() isn't needed anymore, but provide a no-op
    macro definition so as not to create compatibility problems.

diff --git a/src/include/utils/tuplestore.h b/src/include/utils/tuplestore.h
index b46babacd1..76fe9fb428 100644
--- a/src/include/utils/tuplestore.h
+++ b/src/include/utils/tuplestore.h
@@ -17,7 +17,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: tuplestore.h,v 1.8 2003/03/09 02:19:13 tgl Exp $
+ * $Id: tuplestore.h,v 1.9 2003/03/09 03:34:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -41,6 +41,9 @@ extern Tuplestorestate *tuplestore_begin_heap(bool randomAccess,

 extern void tuplestore_puttuple(Tuplestorestate *state, void *tuple);

+/* tuplestore_donestoring() used to be required, but is no longer used */
+#define tuplestore_donestoring(state)  ((void) 0)
+
 /* backwards scan is only allowed if randomAccess was specified 'true' */
 extern void *tuplestore_gettuple(Tuplestorestate *state, bool forward,
                                        bool *should_free);
2021-12-14 18:55:02 +03:00
Onur Tirtir 76b8006a9e
Allow overwriting columnar storage pages written by aborted xacts (#5484)
When refactoring storage layer in #4907, we deleted the code that allows
overwriting a disk page previously written but not known by metadata.

Readers can see the change that introduced the code allows doing so in
commit a8da9acc63.

The reasoning was that; as of 10.2, we started aligning page
reservations (`AlignReservation`) for subsequent writes right after
allocating pages from disk. That means, even if writer transaction
fails, subsequent writes are guaranteed to allocate a new page and write
to there. For this reason, attempting to write to a page allocated
before is not possible for a columnar table that user created when using
v10.2.x.

However, since the older versions of columnar doesn't do that, following
example scenario can still result in writing to such disk page, even if
user now upgraded to v10.2.x. This is because, when upgrading storage to
2.0 (`ColumnarStorageUpdateIfNeeded`), we calculate `reservedOffset` of
the metapage based on the highest used address known by stripe
metadata (`GetHighestUsedAddressAndId`). However, stripe metadata
doesn't have entries for aborted writes. As a result, highest used
address would be computed by ignoring pages that are allocated but not
used.

- User attempts writing to columnar table on Citus v10.0x/v10.1x.
- Write operation fails for some reason.
- User upgrades Citus to v10.2.x.
- When attempting to write to same columnar table, they hit to "attempt
  to write columnar data .." error since write operation done in the
  older version of columnar already allocated that page, and now we are
  overwriting it.

For this reason, with this commit, we re-do the change done in
a8da9acc63.

And for the reasons given above, it wasn't possible to add a test for
this commit via usual code-paths. For this reason, added a UDF only for
testing purposes so that we can reproduce the exact scenario in our
regression test suite.
2021-11-26 07:51:13 +01:00