The first rule of writing fast programs: don't use dynamic memory
allocation!
Brings back some performance for the `SELECT 1` micro-benchmark,
although we're still not where we need to be.
This is a purely syntactic PR. It doesn't change behavior, just rewrites
some loops and removes unneeded parts, like lifetime annotations and
references. Mainly because the Clippy and IDE warnings get annoying.
Don't worry about the number of commits, I just separated based on type
of change.
Closes#732
cli: add a new argument to select I/O backend (more than one option only for Linux with io_uring feature).
cli: make both Limbo::new() and Limbo::open_db() use get_io(), unifying parsing of database path and eliminating duplicated code.
The database object is a way to represent state that's shared across
multiple connections. We don't want to release that object until all
connections are closed.
The name "row result" is confusing because it really *is* a result from
a step() call. The only difference is how a row is represented as we
return from VDBE or from a statement.
Therefore, rename RowResult to StepResult.
This adds an interrupt() method to Statement that allows apps to
interrupt a running statement. Please note that this is different from
`sqlite3_interrupt()` which interrupts all ongoing operations in a
database. Although we want to support that too, per statement interrupt
is much more useful to apps.
Since page cache is now shared by default, we need to cache pages by
page number and something else. I chose to go with max_frame of
connection, because this connection will have a max_frame set until from
the start of a transaction until the end of it.
With key pairs of (pgno, max_frame) we make sure each connection is
caching based on the snapshot it is at as two different connections
might have the same pageno being using but a different frame. If both
have same max_frame then they will share same page.
Closes#468
