Static analysis found an issue where we could dereference `NULL`, because
`CreateDummyPlacement` could return `NULL` when there were no workers. This
PR changes it so that it never returns `NULL`, which was intended by
@marcocitus when doing this change: https://github.com/citusdata/citus/pull/3887/files#r438136433
While adding tests for citus on a single node I also added some more basic
tests and it turns out we error out on repartition joins. This has been
present since `shouldhaveshards` was introduced and is not trivial to fix.
So I created a separate issue for this: https://github.com/citusdata/citus/issues/3996
* Not append empty task in ExtractLocalAndRemoteTasks
ExtractLocalAndRemoteTasks extracts the local and remote tasks. If we do
not have a local task the localTaskPlacementList will be NIL, in this
case we should not append anything to local tasks. Previously we would
first check if a task contains a single placement or not, now we first
check if there is any local task before doing anything.
* fix copy of node task
Task node has task query, which might contain a list of strings in its
fields. We were using postgres copyObject for these lists. Postgres
assumes that each element of list will be a node type. If it is not a
node type it will error.
As a solution to that, a new macro is introduced to copy a list of
strings.
In case we don't care about the tupleStoreState in
ExecuteLocalTaskListExtended, it could be passed as null. In that case
we will get a seg error. This changes it so that a dummy tuple store
will be created when it is null.
Do not use local execution in ExecuteTaskListOutsideTransaction.
As we are going to run the tasks outside transaction, we shouldn't use local execution.
However, there is some problem when using local execution related to
repartition joins, when we solve that problem, we can execute the tasks
coming to this path with local execution.
Also logging the local command is simplified.
normalize job id in worker_hash_partition_table in test outputs.
ExecuteTaskListExtended is the common method for different codepaths,
and instead of writing separate local execution logics in different
codepaths, it makes more sense to have the logic here. We still need to
do some refactoring, this is an initial step.
After this commit, we can run create shard commands locally. There is a
special case with shard creation commands. A create shard command might
have a concatenated query string, however local execution did not know
how to execute a task with multiple query strings. This is also
implemented in this commit. We go over each query in the concatenated
query string and plan/execute them one by one.
A more clean solution to this would be to make sure that each task has a
single query. We currently cannot do that because we need to ensure the
task dependencies. However, it would make sense to do that at some point
and it would simplify the code a lot.
Deparsing and parsing a query can be heavy on CPU. When locally executing
the query we don't need to do this in theory most of the time.
This PR is the first step in allowing to skip deparsing and parsing
the query in these cases, by lazily creating the query string and
storing the query in the task. Future commits will make use of this and
not deparse and parse the query anymore, but use the one from the task
directly.
Jelte Fennema
Marco Slot
SaitTalhaNisanci