Having as little Perl as possible in our repo seems a worthy goal. Sadly
Postgres its Perl based TAP infrastructure was the only way in which we
could
run tests that were hard to do using only SQL commands. This change adds
infrastructure to run such "application style tests" using python and
converts all our existing Perl TAP tests to this new infrastructure.
Some of the helper functions that are added in this PR are currently
unused. Most of these will be used by the CDC PR that depends on this.
Some others are there because they were needed by the PgBouncer test
framework that this is based on, and the functions seemed useful enough
to citus testing to keep.
The main features of the test suite are:
1. Application style tests using a programming language that our
developers know how to write.
2. Caching of Citus clusters in-between tests using the ["fixture"
pattern][fixture] from `pytest` to achieve speedy tests. To make this
work in practice any changes made during a test are automatically
undone. Schemas, replication slots, subscriptions, publications are
dropped at the end of each test. And any changes made by `ALTER SYSTEM`
or manually editing of `pg_hba.conf` are undone too.
3. Automatic parallel execution of tests using the `-n auto` flag that's
added by `pytest-xdist`. This improved the speed of tests greatly with
the similar test framework I created for PgBouncer. Right now it doesn't
help much yet though, since this PR only adds two tests (one of which
takes ~10 times longer than the other).
Possible future improvements are:
1. Clean up even more things at the end of each test (e.g. users that
were created). These are fairly easy to add, but I have not done so yet
since they were not needed yet for this PR or the CDC PR. So I would not
be able to test the cleanup easily.
2. Support for query block detection similar to what we can now do using
isolation tests.
[fixture]: https://docs.pytest.org/en/6.2.x/fixture.html
Description:
Implementing CDC changes using Logical Replication to avoid
re-publishing events multiple times by setting up replication origin
session, which will add "DoNotReplicateId" to every WAL entry.
- shard splits
- shard moves
- create distributed table
- undistribute table
- alter distributed tables (for some cases)
- reference table operations
The citus decoder which will be decoding WAL events for CDC clients,
ignores any WAL entry with replication origin that is not zero.
It also maps the shard names to distributed table names.
ci/fix_styles.sh were complaining about `black` and `isort` packages are
not found even if I `pipenv install --dev` due to broken lock file. I
regenerated the lock file and now it works fine. We also wanted to
upgrade required python version for the pipfile.
In #6720 I'm adding a `pytest` based testing framework. This adds the
dependencies for those. They have already been [merged into our docker
files][the-process-merge] in the the-process repo preparation for #6720.
But by not having them on our citus main branch it is impossible to
make changes to the Pipfile, because our CI Dockerfiles and master
are out of date.
Since #6720 will need some more discussion and might take a few more
weeks to be merged, this takes out the Pipfile changes. By merging this
PR we can unblock new Pipfile changes.
Unblocks and partially addresses #6766
[the-process-merge]: https://github.com/citusdata/the-process/pull/117
A branch that touches a set of upgrade scripts is also expected to touch
corresponding downgrade scripts as well. To ensure that I introduce a
new CI script. If this script fails, read the output and make sure you
update the downgrade scripts in the printed list.
Our repo was complaining about the cryptography package being
vulnerable. This updates it, including our mitmproxy fork, because that
was pinning an outdated version.
Relevant commit on our mitmproxy fork:
2fd18ef051
Relevant PR on the-process:
https://github.com/citusdata/the-process/pull/112
Postgres got minor updates this starts using the images with the latest
version for our tests.
These new Postgres versions caused a compilation issue in PG14 and PG13
due to some function being backported that we had already backported
ourselves. Due this backport being a static inline function it doesn't
matter who provides this and there will be no linkage errors when either
running old Citus packages on new PG versions or the other way around.
We started getting this error in CI:
```
Summary coverage rate:
lines......: 43.4% (28347 of 65321 lines)
functions..: 53.2% (2544 of 4786 functions)
branches...: no data found
fatal: detected dubious ownership in repository at '/home/circleci/project'
To add an exception for this directory, call:
git config --global --add safe.directory /home/circleci/project
Error: exit status 128
```
This fixes that by running the proposed command to command in CI. This
error is
related to a CVE that does not apply to this case, since this is not a
multiuser
system.
Commit on git itself that fixed the CVE:
8959555cee
This PR adds a new CI workflow named ```flaky-test``` to run flaky test
detection on newly introduced regression tests.
Co-authored-by: Jelte Fennema <github-tech@jeltef.nl>
Finds core files from correct path on CI. According to default core
pattern on CI, core is generated at the location relative to binary is
executed.
It can be safe to set core pattern before running binary but to change a
kernel param(in our case kernel.core_pattern), you need related
privilege in docker container. Or you have to change it at image build.
But, by default, on CI machines, kernel pattern contains a relative path
to binary + pid + process name, so we do not need to set it explicitly
for now. (Example core file name on CI machine:
`core.2559.!usr!lib!postgresql!14!bin!postgres`)
Depends on https://github.com/citusdata/the-process/pull/92Closes: #6371
Updates test dependencies to not rely on a known vulnerable dependency
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
We have lots of flaky tests in CI and most of these random failures are
very hard/impossible to reproduce locally. This adds a job definition to
CI that allows adding a temporary job to rerun the same test in CI a lot
of times. This will very often reproduce the random failures. If you
then try to change the test or code to fix the random failure, you can
confirm that it's indeed fixed by using this job.
A future improvement to this job would be to run it (or a variant of it)
automatically for every newly added test, and maybe even changed tests.
This is not implemented in this PR.
An example of this job running can be found here:
https://app.circleci.com/pipelines/github/citusdata/citus/26682/workflows/a2638385-35bc-443c-badc-7713a8101313
* Adjust configure script to allow PG15
* Adds copy of ruleutils_14.c as ruleutils_15.c
* Uses get_namespace_name_or_temp in ruleutils_15.c
Relevant PG commit:
48c5c9068211e0a04fd9553c8714b2821ed3ad17
* Clean up code using "(expr) ? true : false" in ruleutils_15.c
Relevant PG commit:
fd0625c7a9c679c0c1e896014b8f49a489c3a245
* Change varno from Index (unsigned int) to int in ruleutils_15.c
Relevant PG commit:
e3ec3c00d85bd2844ffddee83df2bd67c4f8297f
* Adds find_recursive_union to ruleutils_15.c
Relevant PG commit:
3f50b82639637c9908afa2087de7588450aa866b
* Fix display of SQL-std func's args in INSERT/SELECT in ruleutils_15.c
Relevant PG commit:
a8d8445a7b2f80f6d0bfe97b19f90bd2cbef8759
* Fix ruleutils_15.c's dumping of whole-row Vars in more contexts
Relevant PG commit:
43c2175121c829c8591fc5117b725f1f22bfb670
* Fix assorted missing logic for GroupingFunc nodes in ruleutils_15.c
Relevant PG commit:
2591ee8ec44d8cbc8e1226550337a64c684746e4
* Adds grammar support for SQL/JSON clauses in ruleutils_15.c
Relevant PG commit:
f79b803dcc98d707450e158db3638dc67ff8380b
* Adds SQL/JSON constructors to ruleutils_15.c
Relevant PG commits:
f4fb45d15c59d7add2e1b81a9d477d0119a9691a
cc7401d5ca498a84d9b47fd2e01cebd8e830e558
* Adds support for MERGE in ruleutils_15.c
Relevant PG commit:
7103ebb7aae8ab8076b7e85f335ceb8fe799097c
* Add IS JSON predicate to ruleutils_15.c
Relevant PG commit:
33a377608fc29cdd1f6b63be561eab0aee5c81f0
* Add SQL/JSON query functions to ruleutils_15.c
Relevant PG commit:
1a36bc9dba8eae90963a586d37b6457b32b2fed4
* Adds three different SQL/JSON values to ruleutils_15.c
Relevant PG commits:
606948b058dc16bce494270eea577011a602810e
49082c2cc3d8167cca70cfe697afb064710828ca
* Adds JSON table functions in ruleutils_15.c
Relevant PG commit:
4e34747c88a03ede6e9d731727815e37273d4bc9
* Add PLAN function for JSON table in ruleutils_15.c
Relevant PG commit:
fadb48b00e02ccfd152baa80942de30205ab3c4f
* Remove extra blank lines before block-closing braces ruleutils_15.c
Relevant PG commit:
24d2b2680a8d0e01b30ce8a41c4eb3b47aca5031
* set_deparse_plan: Reuse variable to appease Coverity ruleutils_15.c
Relevant PG commit:
e70813fbc4aaca35ec012d5a426706bd54e4acab
* Mechanical code beautification ruleutils_15.c
Relevant PG commit:
23e7b38bfe396f919fdb66057174d29e17086418
* Rename value_type to item_type in ruleutils_15.c
Relevant PG commit:
3ab9a63cb638a1fd99475668e2da9c237495aeda
* Show 'AS "?column?"' explicitly when it's important in ruleutils_15.c
Relevant PG commit:
c7461fc25558832dd347a9c8150b0f1ed85e36e8
* Fix ruleutils_15.c issues with dropped cols in funcs-returning-composite
Relevant PG commit:
c1d1e8469c77ce6b8e5310955580b4a3eee7fe96
* Change comment regarding functions returning composite in ruleutils_15.c
Relevant PG commit:
c2fa113ddb1117b1f03e91960f65d5d7d8a90270
* Replace int nodes with bool nodes where needed
In PG15, Boolean nodes are added. Pre PG15, internal Boolean values
in Create Role commands were represented by Integer nodes. This
commit replaces int nodes logic with bool nodes logic where needed.
Mostly there are CREATE ROLE logic changes.
Relevant PG commit:
941460fcf731a32e6a90691508d5cfa3d1f8eeaf
* Handle new option colliculocale in CREATE COLLATION logic
In PG15, there is an added option to use ICU as global locale provider.
pg_collation has three locale-related fields: collcollate and collctype,
which are libc-related fields, and a new one colliculocale, which is the
ICU-related field. Only the libc-related fields or the ICU-related field
is set, never both.
Relevant PG commits:
f2553d43060edb210b36c63187d52a632448e1d2
54637508f87bd5f07fb9406bac6b08240283be3b
* Add PG15 tests to CI using test images that have 15beta2 (#6093)
* Change warning message in pg_signal_backend()
Relevant PG commit:
7fa945b857cc1b2964799411f1633468826861ff
* Revert "Add missing ifdef for PG 15"
This reverts commit c7b51025ab.
* Fixes tests for ALTER TRIGGER RENAME consistency for part. tables
Relevant PG commit:
80ba4bb383538a2ee846fece6a7b8da9518b6866
* Prevent creating child triggers on partitions when adding new node
Pre PG15, tgisinternal is true for a "child" trigger on a partition
cloned from the trigger on the parent.
In PG15, tgisinternal is false in that case. However, we don't want to
create this trigger on the partition since it will create a conflict
when we try to attach the partition to the parent table:
ERROR: trigger "..." for relation "{partition_name}" already exists
Relevant PG commit:
f4566345cf40b068368cb5617e61318da60676ec
* Fix tests for generated columns dependency changes
In PG15, For GENERATED columns, all dependencies of the generation
expression are recorded as NORMAL dependencies of the column itself.
This requires CASCADE to drop generated cols with the original col.
PRE PG15, dependencies were recorded as AUTO, with which
generated columns are silently dropped with the original column.
Relevant PG commit:
cb02fcb4c95bae08adaca1202c2081cfc81a28b5
* Explicitly cast catalog "char" column to text before concatenation
Relevant PG commit:
07eee5a0dc642d26f44d65c4e6263304208e8583
* Remove 'AS "?column?"' from test outputs
There were some instances in the following tst outputs
in planning debug outputs where AS "?column?" is added.
We add a normalization rule to remove it as it is not
important.
cte_inline.out
recursive_relation_planning_restriction_pushdown.out
Relevant PG commit:
c7461fc25558832dd347a9c8150b0f1ed85e36e8
* Use pg_backup_stop(PG15) instead of pg_stop_backup(PG<15)
Add an alternative test output because of the change in the
backup modes of Postgres. Specifically here, there is a renaming
issue: pg_stop_backup PRE PG15 vs pg_backup_stop PG15+
The alternative output can be deleted when we drop support for PG14
Relevant PG commit:
39969e2a1e4d7f5a37f3ef37d53bbfe171e7d77a
* Adds citus.mitmfifo GUC
Previously we setting this configuration parameter
in the fly for failure tests schedule.
However, PG15 doesn't allow that anymore: reserved prefixes
like "citus" cannot be used to set non-existing GUCs.
Relevant PG commit:
88103567cb8fa5be46dc9fac3e3b8774951a2be7
* Handles EXPLAIN output diffs in PG15 - Extra result lines
To handle extra "Result" lines in explain outputs, we add explain
method to multi_test_helpers.sql file
- plan_without_result_lines() is added for cases where we want the
whole explain output with only "Result" lines removed
* Handles EXPLAIN output diffs in PG15, Hash Agg/Join leverage
To handle differences in usage of GroupAggregate vs HashAggregate
or Merge Join vs Hash join in cases where this detail doesn't
seem to matter, we use coordinator_plan().
- coordinator_plan() is updated to remove "Result" lines
There are some cases where we have subplans so we add a new
function that prints all Task Count lines as well
- coordinator_plan_with_subplans()
Still not sure of the relevant PG commit
Could be db0d67db2401eb6238ccc04c6407a4fd4f985832
but disabling enable_group_by_reordering didn't help.
* Handles EXPLAIN output diffs in PG15: enable_group_by_reordering
Relevant PG commit
db0d67db2401eb6238ccc04c6407a4fd4f985832
* Normalizes Memory Usage, Buckets, Batches for PG15 explain diffs
We create a new function in multi_test_helpers, which is similar
to explain_merge function in PG15. This explain helper function
normalies Memory Usage, Buckets and Batches, and we use it in the
tests which give a different output for PG15.
* Bump test images to 15beta3 (#6172)
* Omit namespace in post-copy errmsg
Relevant PG commit:
069d33d0c5a021601245e44df77a0423ddd69359
* Handles EXPLAIN output diffs in PG15: extra arrows&result lines
To handle extra "->" arrows resulting from extra Result lines
in explain outputs, we add the following explain method to
multi_test_helpers.sql file
- plan_without_arrows() is added for cases where we want the
whole explain output without arrows and without Result lines
* Alters public schema's owner to pg_database_owner in PG15
In PG15, public schema is owned by pg_database_owner role.
In multi_extension, we drop and recreate the ppublic schema,
hence its owner become the default user in our tests, postgres.
Change that to pg_database_owner for PG15 consistency.
This results in alternative test output for public schema grants
in the following test:
grant_on_schema_propagation.sql
Relevant PG commit: b073c3ccd06e4cb845e121387a43faa8c68a7b62
* Add alternative test outputs for change in Insert Select display
citus_local_tables_queries.sql
coordinator_shouldhaveshards.sql
cte_inline.sql
insert_select_repartition.sql
intermediate_result_pruning.sql
local_shard_execution.sql
local_shard_execution_replicated.sql
multi_deparse_shard_query.sql
multi_insert_select.sql
multi_insert_select_conflict.sql
multi_mx_insert_select_repartition.sql
mx_coordinator_shouldhaveshards.sql
single_node.sql
Relevant PG commit:
a8d8445a7b2f80f6d0bfe97b19f90bd2cbef8759
* Fixes columnar tap tests for PG15
In PG15, Perl test modules have been moved to a new namespace.
Also, postgres node new() and get_new_node() methods have been
unified to one method: new()
We create separate tap tests for PG13/14 and PG15+
and update the Makefiles accordingly.
Relevant PG commits:
201a76183e2056c2217129e12d68c25ec9c559c8
b3b4d8e68ae83f432f43f035c7eb481ef93e1583
* Handles EXPLAIN output diffs in PG15: HashAgg Leverage,alt. output
Still not sure of the relevant PG commit
Could be db0d67db2401eb6238ccc04c6407a4fd4f985832
but disabling enable_group_by_reordering didn't help.
If a test fails sometimes the diff of the output isn't very helpful. In
those cases looking at the postgres logs can help a lot. We were only
storing these logs as artifacts for arbitrary config tests and tap
tests, now we also store them for our regular test runs.
In CI sometimes failure_setup will fail with the following error:
```diff
SELECT master_add_node('localhost', :worker_2_proxy_port); -- an mitmproxy which forwards to the second worker
- master_add_node
----------------------------------------------------------------------
- 2
-(1 row)
-
+ERROR: connection to the remote node localhost:9060 failed with the following error: could not connect to server: Connection refused
+ Is the server running on host "localhost" (127.0.0.1) and accepting
+ TCP/IP connections on port 9060?
+could not connect to server: Connection refused
+ Is the server running on host "localhost" (127.0.0.1) and accepting
+ TCP/IP connections on port 9060?
+could not connect to server: Cannot assign requested address
+ Is the server running on host "localhost" (::1) and accepting
+ TCP/IP connections on port 9060?
diff -dU10 -w /home/circleci/project/src/test/regress/expected/failure_online_move_shard_placement.out /home/circleci/project/src/test/regress/results/failure_online_move_shard_placement.out
```
This then breaks all the tests run after it as well, because we're
missing one worker node.
Locally I was able to reproduce this error by sleeping for 10 seconds in
the forked process sleep before actually starting mitmproxy. So I'm
expecting what's happening in CI is that due to limited resources,
mitmproxy is not up yet when we try to add its port as a workernode.
This PR fixes this by waiting until mitmproxy is listening on its socket
before actually starting to run our tests. This fixed it locally for me
when I made the forked process sleep for 10 seconds before starting
mitmproxy.
In passing it also improves the detection and errors that we already
had for the case where something was already listening on the
mitmproxy port.
Because both @gledis69 and me were changing things in our CI images
at the same time this also includes a bump of the style checker tools.
Closes#6200
For working on initial changes to postgres beta versions make the version check in `./configure` default, but optional.
Normal users will still get the postgres version check error when building on other postgres versions, however, advanced users can use this flag to force configure to pass and find the compilation errors Citus would run into.
Use of the flag is not advised for users not understanding what this does.
* Blocking split setup
* Add missing type
* Missing API from Metadata Sync
* Shard Split e2e code
* Worker Split Copy DestReceiver skeleton
* Basic destreceiver code
* worker_split_copy UDF
* UDF calling
* Split points are text
* Isolate Tenant and Split Shard Unification
* Fixing executor and misc
* Reindent code
* Fixing UDF definitions
* Hello World Local Copy works
* Remote copy hello world works
* Local and Remote binary test
* Fixing text local copy and adding tests
* Hello World shard split works
* Negative tests
* Blocking Split workflow works
* Refactor
* Bug fix
* Reindent
* Cleaning up and adding comments
* Basic test for shard split workflow
* ReIndent
* Circle CI integration
* Removing include causing circle-ci build failure
* Remove SplitCopyDestReceiver and use PartitionedResultDestReceiver
* Add support for citus.enable_binary_protocol
* Reindent
* Fix build break
* Update Test
* Cleanup on catch
* Addressing open comments
* Update downgrade script and quote schema/table in COPY statement
* Fix metadata sync issue. Update regression test
* Isolation test and bug fix
* Add Isolation test, fix foreign constraint deadlock issue
* Misc code review comments
* Test name needing to be quoted
* Refactor code from review comments
* Explaining shardGroupSplitIntervalListList
* Fix upgrade & downgrade
* Fix broken test
* Test fix Round 2
* Fixing bug and modifying test appropriately
* Fully qualify copy udf name. Run Reindent
* Address PR comments
* Fix null handling when creating AuxiliaryStructures
* Ensure local copy is triggered in tests
* Limit max shards that can be created with split
* Test failure fix
* Remove split_mode and use shard_transfer_mode instead'
* Fix test failure
* Fix test failure
* Fixing permission issue when splitting non-superuser owned tables
* Fix test expected output
* Remove extra space
* Fix test
* attempt to fix test
* Addressing Marco's PR comment
* Only clean shards created by workflow
* Remove from merge
* Update test
This PR makes all of the features open source that were previously only
available in Citus Enterprise.
Features that this adds:
1. Non blocking shard moves/shard rebalancer
(`citus.logical_replication_timeout`)
2. Propagation of CREATE/DROP/ALTER ROLE statements
3. Propagation of GRANT statements
4. Propagation of CLUSTER statements
5. Propagation of ALTER DATABASE ... OWNER TO ...
6. Optimization for COPY when loading JSON to avoid double parsing of
the JSON object (`citus.skip_jsonb_validation_in_copy`)
7. Support for row level security
8. Support for `pg_dist_authinfo`, which allows storing different
authentication options for different users, e.g. you can store
passwords or certificates here.
9. Support for `pg_dist_poolinfo`, which allows using connection poolers
in between coordinator and workers
10. Tracking distributed query execution times using
citus_stat_statements (`citus.stat_statements_max`,
`citus.stat_statements_purge_interval`,
`citus.stat_statements_track`). This is disabled by default.
11. Blocking tenant_isolation
12. Support for `sslkey` and `sslcert` in `citus.node_conninfo`
We do not use comments starting with # in spec files because it creates
errors from C preprocessor that expects directives after this character.
Instead use C style comments, i.e:
// single line comment
You can also use multiline comments as well
/*
* multi line comment
*/
This PR is fixing 2 separate issues related to the local run of citus upgrade tests.
d3e7c825ab fixes the issue that, with our new testing infrastructure, we moved/renamed some of existing folders. This created a problem for local runs of citus upgrade tests since some paths were sensitive to such changes. This commit tries to make it more generic so that this issue is less likely to happen in the future, while also fixing the current issue.
93de6b60c3 we are fixing an issue that a new environment variable was added for citus upgrade tests, which is defined in the CI. 0cb51f8c37/.circleci/config.yml (L294)
This environment variable wasn't set in our local runs hence it would create problems. Instead of defining this environment variable in the local run, we change the citus_upgrade run command to use an existing env variable, which is now also set in the CI.
There is a vulnerability in mitmproxy with the version we are using.
It would be hard to exploit anything with regards to the artifacts we ship as its only used in our test suite. Still its good hygiene to _not_ use software with known vulnerabilities.
This PR updates the version of python, mitmproxy and the crypto libraries used.
The latest version of mitmproxy for python 3.6 is not patched, hence the upgrade of python.
For our CI images this cascades into upgrading debian as well :)
For CI we bake these versions in our images so we need to update them as well.
Changes to the CI images: https://github.com/citusdata/the-process/pull/65
To run tests in parallel use:
```bash
make check-arbitrary-configs parallel=4
```
To run tests sequentially use:
```bash
make check-arbitrary-configs parallel=1
```
To run only some configs:
```bash
make check-arbitrary-base CONFIGS=CitusSingleNodeClusterConfig,CitusSmallSharedPoolSizeConfig
```
To run only some test files with some config:
```bash
make check-arbitrary-base CONFIGS=CitusSingleNodeClusterConfig EXTRA_TESTS=dropped_columns_1
```
To get a deterministic run, you can give the random's seed:
```bash
make check-arbitrary-configs parallel=4 seed=12312
```
The `seed` will be in the output of the run.
In our regular regression tests, we can see all the details about either planning or execution but this means
we need to run the same query under different configs/cluster setups again and again, which is not really maintanable.
When we don't care about the internals of how planning/execution is done but the correctness, especially with different configs
this infrastructure can be used.
With `check-arbitrary-configs` target, the following happens:
- a bunch of configs are loaded, which are defined in `config.py`. These configs have different settings such as different shard count, different citus settings, postgres settings, worker amount, or different metadata.
- For each config, a separate data directory is created for tests in `tmp_citus_test` with the config's name.
- For each config, `create_schedule` is run on the coordinator to setup the necessary tables.
- For each config, `sql_schedule` is run. `sql_schedule` is run on the coordinator if it is a non-mx cluster. And if it is mx, it is either run on the coordinator or a random worker.
- Tests results are checked if they match with the expected.
When tests results don't match, you can see the regression diffs in a config's datadir, such as `tmp_citus_tests/dataCitusSingleNodeClusterConfig`.
We also have a PostgresConfig which runs all the test suite with Postgres.
By default configs use regular user, but we have a config to run as a superuser as well.
So the infrastructure tests:
- Postgres vs Citus
- Mx vs Non-Mx
- Superuser vs regular user
- Arbitrary Citus configs
When you want to add a new test, you can add the create statements to `create_schedule` and add the sql queries to `sql_schedule`.
If you are adding Citus UDFs that should be a NO-OP for Postgres, make sure to override the UDFs in `postgres.sql`.
You can add your new config to `config.py`. Make sure to extend either `CitusDefaultClusterConfig` or `CitusMXBaseClusterConfig`.
On the CI, upon a failure, all logfiles will be uploaded as artifacts, so you can check the artifacts tab.
All the regressions will be shown as part of the job on CI.
In your local, you can check the regression diffs in config's datadirs as in `tmp_citus_tests/dataCitusSingleNodeClusterConfig`.