## Problem
There are several problems with our current statically allocated
`BufferPool`.
1. You cannot open two databases in the same process with different page
sizes, because the `BufferPool`'s `Arena`s will be locked forever into
the page size of the first database. This is the case regardless of
whether the two `Database`s are open at the same time, or if the first
is closed before the second is opened.
2. It is impossible to even write Rust tests for different page sizes
because of this, assuming the test uses a single process.
## Solution
Make `Database` own `BufferPool` instead of it being statically
allocated, so this problem goes away.
Note that I didn't touch the still statically-allocated
`TEMP_BUFFER_CACHE`, because it should continue to work regardless of
this change. It should only be a problem if the user has two or more
databases with different page sizes open simultaneously, because
`TEMP_BUFFER_CACHE` will only support one pool of a given page size at a
time, so the rest of the allocations will go through the global
allocator instead.
## Notes
I extracted this change out from #2569, because I didn't want it to be
smuggled in without being reviewed as an individual piece.
Reviewed-by: Avinash Sajjanshetty (@avinassh)
Closes#2596
Problem
There are several problems with our current statically allocated
`BufferPool`.
1. You cannot open two databases in the same process with different
page sizes, because the `BufferPool`'s `Arena`s will be locked forever
into the page size of the first database. This is the case regardless
of whether the two `Database`s are open at the same time, or if the first
is closed before the second is opened.
2. It is impossible to even write Rust tests for different page sizes because
of this, assuming the test uses a single process.
Solution
Make `Database` own `BufferPool` instead of it being statically allocated, so this
problem goes away.
Note that I didn't touch the still statically-allocated `TEMP_BUFFER_CACHE`, because
it should continue to work regardless of this change. It should only be a problem if
the user has two or more databases with different page sizes open simultaneously, because
`TEMP_BUFFER_CACHE` will only support one pool of a given page size at a time, so the rest
of the allocations will go through the global allocator instead.
Notes
I extracted this change out from #2569, because I didn't want it to be smuggled in without
being reviewed as an individual piece.
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.
- sync engine create pair of databases and they must be isolated but live in the same MemoryIO
- the problem can happen if there will be 2 sync engines with MemoryIO storage layer - as they all will create :memory:-draft and :memory:-synced DBs
- otherwise, in case of schema change, connection will constantly get Database schema is changed error as reprepare logic is implemented in the statement event loop
We have to update the Transaction State before checking for the Schema
Cookie so that we can rollback the transaction later on correctly.
Closes#2535Closes#2549
This PR adds new `updates` column to the CDC table. This column holds
updated fields of the row in the following format:
```
[C boolean values where true set for changed columns]
[C values with updates where NULL is set for not-changed columns]
```
For example:
```
turso> UPDATE t SET y = 'turso', q = 'db' WHERE rowid = 1;
turso> SELECT bin_record_json_object('["x","y","z","q","x","y","z","q"]', updates) as updates FROM turso_cdc;
┌──────────────────────────────────────────────────────────────────┐
│ updates │
├──────────────────────────────────────────────────────────────────┤
│ {"x":0,"y":1,"z":0,"q":1,"x":null,"y":"turso","z":null,"q":"db"} │
└──────────────────────────────────────────────────────────────────┘
```
Also, this column works differently for `ALTER TABLE` statements where
update value for `sql` will be equal to the original `ALTER TABLE`:
```
turso> ALTER TABLE t ADD COLUMN t;
turso> SELECT bin_record_json_object('["type","name","tbl_name","rootpage","sql","type","name","tbl_name","rootpage","sql"]', updates) as updates FROM turso_cdc WHERE rowid = 2;
┌───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ updates │
├───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ {"type":0,"name":0,"tbl_name":0,"rootpage":0,"sql":1,"type":null,"name":null,"tbl_name":null,"rootpage":null,"sql":"ALTER TABLE t ADD COLUMN t;"} │
└───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
```
This will help turso-db to implement logical replication which supports
both column-level updates and schema changes
Closes#2538
Implement very basic views using DBSP
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.
Closes#2530
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.
We should be allocator-agnostic. It is pretty limiting for us to force a
user to use a particular allocator. This is specially restricting for
`no_std` in the future.
Reviewed-by: bit-aloo (@Shourya742)
Reviewed-by: Preston Thorpe <preston@turso.tech>
Closes#2481
