This PR improves the DBSP circuit so that it handles the JOIN operator.
The JOIN operator exposes a weakness of our current model: we usually
pass a list of columns between operators, and find the right column by
name when needed.
But with JOINs, many tables can have the same columns. The operators
will then find the wrong column (same name, different table), and
produce incorrect results.
To fix this, we must do two things:
1) Change the Logical Plan. It needs to track table provenance.
2) Fix the aggregators: it needs to operate on indexes, not names.
For the aggregators, note that table provenance is the wrong
abstraction. The aggregator is likely working with a logical table that
is the result of previous nodes in the circuit. So we just need to be
able to tell it which index in the column array it should use.
This is a collection of fixes for materialized views ahead of adding
support for JOINs.
It is mostly issues with how we assume there is a single table, with a
single delta, but we have to send more than one.
Those are things that are just objectively wrong, so I am sending it
separately to make the JOIN PR smaller.
Reviewed-by: Preston Thorpe <preston@turso.tech>
Closes#3009
We have been ignoring the alias in the logical plan, but we have to keep
it. Implementing joins in particular is made hard without it, because it
is common that one has the same column name in different tables, just
differentiated by the alias
indexes with the naming scheme "sqlite_autoindex_<tblname>_<number>"
are automatically created when a table is created with UNIQUE or
PRIMARY KEY definitions.
these indexes must map to the table definition SQL in definition order,
i.e. sqlite_autoindex_foo_1 must be the first instance of UNIQUE or
PRIMARY KEY and so on.
this commit fixes our autoindex creation / parsing so that this invariant
is upheld.
hell yeah
concurrency tests passing now woosh
finally write tests passed
Most of the cdc tests are passing yay
autoincremeent draft
remove shared schema code that broke transactions
sequnce table should reset if table is drop
fmt
fmt
fmt
This is a first pass on logical plans. The idea is that the DBSP
compiler will have an easier time operating on a logical plan, that
exposes linear algebra operators, than on SQL expr.
To keep this simple, we only support filters, aggregates and projections
for now, and will add more later as we agree on the core of the
implementation.
To make sure that the implementations is reasonable, I tried my best to
generate a couple of logical plans using Datafusion and seeing if we
were generating something similar.
Our plans are not the same as Datafusion's, though. There are two
important differences:
* SQLite is weird, and it allows columns that are not part of the group
by statement to appear in aggregated statements. For example:
select a, count(b) from table group by c; <== that "a" is usually not
permitted and datafusion will reject it. SQLite will be happy to
accept it
* Datafusion will not generate a projection on queries like this:
select sum(hex(a)) from table, and just keep the complex expression
hex(a) inside the aggregation. For DBSP to work well, we'll need an
explicit aggregation there.
Because there are no users yet, I am marking this as [cfg(test)], but
I wanted to put this out there ASAP.
