113 lines
4.0 KiB
Markdown
113 lines
4.0 KiB
Markdown
========================
|
|
CODE SNIPPETS
|
|
========================
|
|
TITLE: Basic Database Operations with sled in Rust
|
|
DESCRIPTION: This snippet demonstrates fundamental operations using the `sled` embedded database in Rust. It covers opening a database tree, inserting and retrieving key-value pairs, performing range queries, deleting entries, and executing an atomic compare-and-swap operation. It also shows how to flush changes to disk for durability.
|
|
|
|
SOURCE: https://github.com/spacejam/sled/blob/main/README.md#_snippet_0
|
|
|
|
LANGUAGE: Rust
|
|
CODE:
|
|
```
|
|
let tree = sled::open("/tmp/welcome-to-sled")?;
|
|
|
|
// insert and get, similar to std's BTreeMap
|
|
let old_value = tree.insert("key", "value")?;
|
|
|
|
assert_eq!(
|
|
tree.get(&"key")?,
|
|
Some(sled::IVec::from("value")),
|
|
);
|
|
|
|
// range queries
|
|
for kv_result in tree.range("key_1".."key_9") {}
|
|
|
|
// deletion
|
|
let old_value = tree.remove(&"key")?;
|
|
|
|
// atomic compare and swap
|
|
tree.compare_and_swap(
|
|
"key",
|
|
Some("current_value"),
|
|
Some("new_value"),
|
|
)?;
|
|
|
|
// block until all operations are stable on disk
|
|
// (flush_async also available to get a Future)
|
|
tree.flush()?;
|
|
```
|
|
|
|
----------------------------------------
|
|
|
|
TITLE: Subscribing to sled Events Asynchronously (Rust)
|
|
DESCRIPTION: This snippet demonstrates how to asynchronously subscribe to events on key prefixes in a `sled` database. It initializes a `sled` database, creates a `Subscriber` for all key prefixes, inserts a key-value pair to trigger an event, and then uses `extreme::run` to await and process incoming events. The `Subscriber` struct implements `Future<Output=Option<Event>>`, allowing it to be awaited in an async context.
|
|
|
|
SOURCE: https://github.com/spacejam/sled/blob/main/README.md#_snippet_1
|
|
|
|
LANGUAGE: Rust
|
|
CODE:
|
|
```
|
|
let sled = sled::open("my_db").unwrap();
|
|
|
|
let mut sub = sled.watch_prefix("");
|
|
|
|
sled.insert(b"a", b"a").unwrap();
|
|
|
|
extreme::run(async move {
|
|
while let Some(event) = (&mut sub).await {
|
|
println!("got event {:?}", event);
|
|
}
|
|
});
|
|
```
|
|
|
|
----------------------------------------
|
|
|
|
TITLE: Iterating Subscriber Events with Async/Await in Rust
|
|
DESCRIPTION: This snippet demonstrates how to asynchronously iterate over events from a `Subscriber` instance in Rust. Since `Subscriber` now implements `Future`, it can be awaited in a loop to process incoming events, enabling efficient prefix watching. The loop continues as long as new events are available.
|
|
|
|
SOURCE: https://github.com/spacejam/sled/blob/main/CHANGELOG.md#_snippet_0
|
|
|
|
LANGUAGE: Rust
|
|
CODE:
|
|
```
|
|
while let Some(event) = (&mut subscriber).await {}
|
|
```
|
|
|
|
----------------------------------------
|
|
|
|
TITLE: Suppressing TSAN Race on Arc::drop in Rust
|
|
DESCRIPTION: This suppression addresses a false positive race detection by ThreadSanitizer in Rust's `Arc::drop` implementation. TSAN fails to correctly reason about the raw atomic `Acquire` fence used after the strong-count atomic subtraction with a `Release` fence in the `Drop` implementation, leading to an erroneous race report.
|
|
|
|
SOURCE: https://github.com/spacejam/sled/blob/main/tsan_suppressions.txt#_snippet_0
|
|
|
|
LANGUAGE: TSAN Suppression
|
|
CODE:
|
|
```
|
|
race:Arc*drop
|
|
```
|
|
|
|
----------------------------------------
|
|
|
|
TITLE: Suppressing TSAN Race on std::thread::local in Rust
|
|
DESCRIPTION: This suppression addresses ThreadSanitizer false positives when using Rust's `std::thread::local`. Similar to `lazy_static`, `std::thread::local` utilizes implicit barriers that TSAN fails to recognize, leading to incorrect race condition reports.
|
|
|
|
SOURCE: https://github.com/spacejam/sled/blob/main/tsan_suppressions.txt#_snippet_2
|
|
|
|
LANGUAGE: TSAN Suppression
|
|
CODE:
|
|
```
|
|
race:std::thread::local
|
|
```
|
|
|
|
----------------------------------------
|
|
|
|
TITLE: Suppressing TSAN Race on lazy_static in Rust
|
|
DESCRIPTION: This suppression targets ThreadSanitizer false positives related to the `lazy_static` crate in Rust. `lazy_static` relies on implicit memory barriers that TSAN does not correctly detect, causing it to report races where none exist.
|
|
|
|
SOURCE: https://github.com/spacejam/sled/blob/main/tsan_suppressions.txt#_snippet_1
|
|
|
|
LANGUAGE: TSAN Suppression
|
|
CODE:
|
|
```
|
|
race:lazy_static
|
|
``` |