Arseniy Volynets authored 5 months ago and Denis Smirnov committed 5 months ago

- When creating Values node in IR we didn't check
that all values rows have the same length.
- This led to panic on earlier pipeline stages:
syntax plan build
- Add a check that all values rows have the same
length

- When adding concat to plan, we had a check
that both concat children are expressions.
- This leads to error, when children are
parameters.
- Replace error with debug assert that checks
for expression | parameter children. Debug assert
is used because it is quiet unlikely that we will
mess up expression children, no need to check it
in release builds.

- Support simple queries that do not select
data from tables. This is similar to `values ..`,
but allows to add aliases for expressions.
- Such selects can also be used in subqueries
- Examples:
```
select 1;
select (select count(*) from t);
select 2 as foo, 3 as bar;

select a from t
where b in (select 100)
```

- We didn't traverse output during subtree
traversal when calculating hash. Some nodes
(Motion, Projection) store non-trivial
information, which allows to distinguish
different plans. We came across this by
collision between two different queries:
```
SELECT w.n FROM t JOIN w ON t.n = w.n
LIMIT 3

SELECT id, count(*) FROM t
GROUP BY id
HAVING id > 2
LIMIT 3
```
These plan happened to have subtrees that match
exactly except for output of projection, that
we didn't traverse.

- fix this by traversing subtree fully

- ValuesRow node have `data` and `output`
fields refer to the same stuff in query
`values (1)`. For except between global
and sharded table we applied special
transformation, in which we cloned
global subtree.
- Subtree cloner didn't respect DAG structure
of our plan: there maybe multiple references
to the same node. Instead it expected a tree.
Fix that

Dmitry Rodionov authored 8 months ago and Denis Smirnov committed 5 months ago

Previous version was using yaml-rust which is marked as unmaintained.
This gets reported by dependency scanner we use for certification.
Though worth noting that serde-yaml itself is now archived. There is a
promising replacement library but no need to hurry with that just yet.
But anyway, we don't need this library in the production build, only
for tests. So, moved it to development dependencies.

Co-authored-by: Denis Smirnov <sd@picodata.io>

- Support like operator with signature:

expr1 LIKE expr2 [ESCAPE expr3]

which returns TRUE only if expr1 matches the
string specified by expr2 (pattern). '_' in
pattern matches any single character, '%'
matches any character 0 or more times. All
other characters match itself according to
case.

- Optional escape clause specifies character
to use for escaping '_' and '%'

- to_params uses subtree iterator to create
parameters for cached query. But our plan
is a DAG, not a tree. We have multiple nodes
referring to the same node, this leads to
situation when we traverse the same subquery
node multiple times. This in term leads to
wrong number of parameters produces by
to_params
- fix this by keeping track of already traversed
parameter nodes in to_params

feat: support additional SubQuery children for any relational operator, interpret SubQuery with single output as expression