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.
This fairly long commit implements persistence for materialized view.
It is hard to split because of all the interdependencies between components,
so it is a one big thing. This commit message will at least try to go into
details about the basic architecture.
Materialized Views as tables
============================
Materialized views are now a normal table - whereas before they were a virtual
table. By making a materialized view a table, we can reuse all the
infrastructure for dealing with tables (cursors, etc).
One of the advantages of doing this is that we can create indexes on view
columns. Later, we should also be able to write those views to separate files
with ATTACH write.
Materialized Views as Zsets
===========================
The contents of the table are a ZSet: rowid, values, weight. Readers will
notice that because of this, the usage of the ZSet data structure dwindles
throughout the codebase. The main difference between our materialized ZSet and
the standard DBSP ZSet, is that obviously ours is backed by a BTree, not a Hash
(since SQLite tables are BTrees)
Aggregator State
================
In DBSP, the aggregator nodes also have state. To store that state, there is a
second table. The table holds all aggregators in the view, and there is one
table per view. That is __turso_internal_dbsp_state_{view_name}. The format of
that table is similar to a ZSet: rowid, serialized_values, weight. We serialize
the values because there will be many aggregators in the table. We can't rely
on a particular format for the values.
The Materialized View Cursor
============================
Reading from a Materialized View essentially means reading from the persisted
ZSet, and enhancing that with data that exists within the transaction.
Transaction data is ephemeral, so we do not materialize this anywhere: we have
a carefully crafted implementation of seek that takes care of merging weights
and stitching the two sets together.
This PR unifies the logic for resolving aggregate functions. Previously,
bare aggregates (e.g. `SELECT max(a) FROM t1`) and aggregates wrapped in
expressions (e.g. `SELECT max(a) + 1 FROM t1`) were handled differently,
which led to duplicated code. Now both cases are resolved consistently.
The added benchmark shows a small improvement:
```
Prepare `SELECT first_name, last_name, state, city, age + 10, LENGTH(email), UPPER(first_name), LOWE...
time: [59.791 µs 59.898 µs 60.006 µs]
change: [-7.7090% -7.2760% -6.8242%] (p = 0.00 < 0.05)
Performance has improved.
Found 10 outliers among 100 measurements (10.00%)
8 (8.00%) high mild
2 (2.00%) high severe
```
For an existing benchmark, no change:
```
Prepare `SELECT first_name, count(1) FROM users GROUP BY first_name HAVING count(1) > 1 ORDER BY cou...
time: [11.895 µs 11.913 µs 11.931 µs]
change: [-0.2545% +0.2426% +0.6960%] (p = 0.34 > 0.05)
No change in performance detected.
Found 8 outliers among 100 measurements (8.00%)
1 (1.00%) low severe
2 (2.00%) high mild
5 (5.00%) high severe
```
Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com>
Reviewed-by: Preston Thorpe <preston@turso.tech>
Closes#2884
Aggregate functions cannot be nested, and this is validated during the
translation of aggregate function arguments. Therefore, traversing their
child expressions is unnecessary.
Handled in the same way as in `prepare_one_select_plan` for bare
function calls. In `prepare_one_select_plan`, however, resolving
external scalar functions is performed unnecessarily twice.
This commit consolidates the creation of the Aggregate struct, which was
previously handled differently in `prepare_one_select_plan` and
`resolve_aggregates`. That discrepancy caused inconsistent handling of
zero-argument aggregates.
The queries added in the new tests would previously trigger a panic.
A lot of the structures we have - like the ones under Schema, are
specific for materialized views. In preparation to adding normal views,
rename them, so things are less confusing.
I'm not sure how much this will clash with @TcMits's parser rewrite,
hopefully not too much. If it does and we eventually have to remove it,
at least we'll have two new regression tests.
Closes https://github.com/tursodatabase/turso/issues/2484Closes#2499
This is just the bare minimum that I needed to convince myself that this
approach will work. The only views that we support are slices of the
main table: no aggregations, no joins, no projections.
drop view is implemented.
view population is implemented.
deletes, inserts and updates are implemented.
much like indexes before, a flag must be passed to enable views.
This change extends table-valued function support by allowing arguments
to be column references, not only literals.
Virtual tables can now reject a plan by returning an error from
best_index (e.g., when a TVF argument references a table that appears
later in the join order). The planner using this information excludes
invalid plans during join order search.
Different scan parameters are required for different table types.
Currently, index and iteration direction are only used by B-tree tables,
while the remaining table types don’t require any parameters. Planning
access to virtual tables, however, will require passing additional
information from the planner, such as the virtual table index (distinct
from a B-tree index) and the constraints that must be forwarded to the
`filter` method.
Closes: #1947
This PR replaces the `Name(pub String)` struct with a `Name` enum that
explicitly models how the name appeared in the source either as an
unquoted identifier (`Ident`) or a quoted string (`Quoted`).
In the process, the separate `Id` wrapper type has been coalesced into
the `Name` enum, simplifying the AST and reducing duplication in
identifier handling logic.
While this increases the size of some AST nodes (notably
`yyStackEntry`).
cc: @levydsa
Reviewed-by: Levy A. (@levydsa)
Reviewed-by: Preston Thorpe (@PThorpe92)
Closes#2251
Support for attaching databases. The main difference from SQLite is that
we support an arbitrary number of attached databases, and we are not
bound to just 100ish.
We for now only support read-only databases. We open them as read-only,
but also, to keep things simple, we don't patch any of the insert
machinery to resolve foreign tables. So if an insert is tried on an
attached database, it will just fail with a "no such table" error - this
is perfect for now.
The code in core/translate/attach.rs is written by Claude, who also
played a key part in the boilerplate for stuff like the .databases
command and extending the pragma database_list, and also aided me in
the test cases.
This commit replaces the `Name(pub String)` struct with a `Name` enum that
explicitly models how the name appeared in the source either as an
unquoted identifier (`Ident`) or a quoted string (`Quoted`).
In the process, the separate `Id` wrapper type has been coalesced into the
`Name` enum, simplifying the AST and reducing duplication in identifier
handling logic.
While this increases the size of some AST nodes (notably `yyStackEntry`),
it improves correctness and makes source structure more explicit for
later phases.
I ended up hitting #1974 today and wanted to fix it. I worked with
Claude to generate a more comprehensive set of queries that could fail
aside from just the insert query described in the issue. He got most of
them right - lots of cases were indeed failing. The ones that were
gibberish, he told me I was absolutely right for pointing out they were
bad.
But alas. With the test cases generated, we can work on fixing it. The
place where the assertion was hit, all we need to do there is return
true (but we assert that this is indeed a string literal, it shouldn't
be anything else at this point).
There are then just a couple of places where we need to make sure we
handle double quotes correctly. We already tested for single quotes in a
couple of places, but never for double quotes.
There is one funny corner case where you can just select "col" from tbl,
and if there is no column "col" on the table, that is treated as a
string literal. We handle that too.
Fixes#1974
With this change, the following two queries are considered equivalent:
```sql
SELECT value FROM generate_series(5, 50);
SELECT value FROM generate_series WHERE start = 5 AND stop = 50;
```
Arguments passed in parentheses to the virtual table name are now
matched to hidden columns.
Column references are still not supported as table-valued function
arguments. The only difference is that previously, a query like:
```sql
SELECT one.value, series.value
FROM (SELECT 1 AS value) one, generate_series(one.value, 3) series;
```
would cause a panic. Now, it returns a proper error message instead.
Adding support for column references is more nuanced for two main
reasons:
- We need to ensure that in joins where a TVF depends on other tables,
those other tables are processed first. For example, in:
```sql
SELECT one.value, series.value
FROM generate_series(one.value, 3) series, (SELECT 1 AS value) one;
```
the one table must be processed by the top-level loop, and series must
be nested.
- For outer joins involving TVFs, the arguments must be treated as ON
predicates, not WHERE predicates.
We're now mixing different error messages, which makes compatibility
testing pretty hard. Unify on a single, SQLite compatible error message
"no such table".
Makes it easier to test the feature:
```
$ cargo run -- --experimental-indexes
Limbo v0.0.22
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database
limbo> CREATE TABLE t(x);
limbo> CREATE INDEX t_idx ON t(x);
limbo> DROP INDEX t_idx;
```
Previously, queries like:
```
SELECT
CASE WHEN c0 != 'x' THEN group_concat(c1, ',') ELSE 'x' END
FROM t0
GROUP BY c0;
```
would return incorrect results because c0 was not copied during the
aggregation loop into a register accessible to the logic processing the
grouped results (e.g., the CASE WHEN expression in this example).
The same issue applied to expressions in the HAVING and ORDER BY clauses.
