ConnParams(AuthInfo and PoolInfo) gets a snapshot, which will block the
remote connectinos to localhost. And the release of snapshot will be
blocked by the snapshot. This leads to a deadlock.
We warm up the conn params hash before starting a new transaction so
that the entries will already be there when we start a new transaction.
Hence GetConnParams will not get a snapshot.
* Columnar: use clause Vars for chunk group filtering.
This solves #4780 and also provides a cleaner separation between chunk
group filtering and projection pushdown.
* Columnar: sort and deduplicate Vars pulled from clauses.
* Columnar: cleanup variable names.
* Columnar: remove alternate test output.
* Columnar: do not recurse when looking for whereClauseVars.
Co-authored-by: Jeff Davis <jefdavi@microsoft.com>
comparable to https://github.com/citusdata/tools/pull/88
this patch adds checks to the perl script running the testing harness of citus to start the postgres instances via the fixopen binary when present to work around `Interrupted System` call errors on OSX Big Sur.
Earlier versions of Citus (pre 9.0) had a bug where a user was able to get in a situation where a foreign key between two non-colocated tables was allowed. This was caused by the wrongful scoping together with only setting to on of a boolean variable in a loop, causing the `true` from an earlier iteration to leak into a new iteration.
This was 'by accident' solved in a refactor that was executed in the preparation of the 9.0 release. Only recently we had a user running into this and it was tracked down to this behaviour.
Given the dire situation a user could get them self into when running into this bug we have backported a fix to the latest 8.3 release branch.
To make sure this regression does not happen anymore in the future I propose we add the tests from the backport to our mainline.
For reference: https://github.com/citusdata/citus/pull/4840
With https://github.com/citusdata/citus/pull/4806 we enabled
2PC for any non-read-only local task. However, if the execution
is a single task, enabling 2PC (CoordinatedTransactionShouldUse2PC)
hits an assertion as we are not in a coordinated transaction.
There is no downside of using a coordinated transaction for single
task local queries.
* Columnar: fix misnamed file.
* Columnar: make compression not dependent on columnar.h.
* Columnar: rename columnar_metadata_tables.c to columnar_metadata.c.
* Columnar: make customscan not depend on columnar.h.
Co-authored-by: Jeff Davis <jefdavi@microsoft.com>
Because setting the flag doesn't necessarily mean that we'll
use 2PC. If connections are read-only, we will not use 2PC.
In other words, we'll use 2PC only for connections that modified
any placements.
Before this commit, Citus used 2PC no matter what kind of
local query execution happens.
For example, if the coordinator has shards (and the workers as well),
even a simple SELECT query could start 2PC:
```SQL
WITH cte_1 AS (SELECT * FROM test LIMIT 10) SELECT count(*) FROM cte_1;
```
In this query, the local execution of the shards (and also intermediate
result reads) triggers the 2PC.
To prevent that, Citus now distinguishes local reads and local writes.
And, Citus switches to 2PC only if a modification happens. This may
still lead to unnecessary 2PCs when there is a local modification
and remote SELECTs only. Though, we handle that separately
via #4587.
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