Database Refactor

combine service/users data w/ mod unit

split sliding sync related out of service/users

instrument database entry points

remove increment crap from database interface

de-wrap all database get() calls

de-wrap all database insert() calls

de-wrap all database remove() calls

refactor database interface for async streaming

add query key serializer for database

implement Debug for result handle

add query deserializer for database

add deserialization trait for option handle

start a stream utils suite

de-wrap/asyncify/type-query count_one_time_keys()

de-wrap/asyncify users count

add admin query users command suite

de-wrap/asyncify users exists

de-wrap/partially asyncify user filter related

asyncify/de-wrap users device/keys related

asyncify/de-wrap user auth/misc related

asyncify/de-wrap users blurhash

asyncify/de-wrap account_data get; merge Data into Service

partial asyncify/de-wrap uiaa; merge Data into Service

partially asyncify/de-wrap transaction_ids get; merge Data into Service

partially asyncify/de-wrap key_backups; merge Data into Service

asyncify/de-wrap pusher service getters; merge Data into Service

asyncify/de-wrap rooms alias getters/some iterators

asyncify/de-wrap rooms directory getters/iterator

partially asyncify/de-wrap rooms lazy-loading

partially asyncify/de-wrap rooms metadata

asyncify/dewrap rooms outlier

asyncify/dewrap rooms pdu_metadata

dewrap/partially asyncify rooms read receipt

de-wrap rooms search service

de-wrap/partially asyncify rooms user service

partial de-wrap rooms state_compressor

de-wrap rooms state_cache

de-wrap room state et al

de-wrap rooms timeline service

additional users device/keys related

de-wrap/asyncify sender

asyncify services

refactor database to TryFuture/TryStream

refactor services for TryFuture/TryStream

asyncify api handlers

additional asyncification for admin module

abstract stream related; support reverse streams

additional stream conversions

asyncify state-res related

Signed-off-by: Jason Volk <jason@zemos.net>

src/database/map/count.rs

@@ -0,0 +1,36 @@
+use std::{fmt::Debug, future::Future};
+
+use conduit::implement;
+use futures::stream::StreamExt;
+use serde::Serialize;
+
+use crate::de::Ignore;
+
+/// Count the total number of entries in the map.
+#[implement(super::Map)]
+#[inline]
+pub fn count(&self) -> impl Future<Output = usize> + Send + '_ { self.keys::<Ignore>().count() }
+
+/// Count the number of entries in the map starting from a lower-bound.
+///
+/// - From is a structured key
+#[implement(super::Map)]
+#[inline]
+pub fn count_from<'a, P>(&'a self, from: &P) -> impl Future<Output = usize> + Send + 'a
+where
+	P: Serialize + ?Sized + Debug + 'a,
+{
+	self.keys_from::<Ignore, P>(from).count()
+}
+
+/// Count the number of entries in the map matching a prefix.
+///
+/// - Prefix is structured key
+#[implement(super::Map)]
+#[inline]
+pub fn count_prefix<'a, P>(&'a self, prefix: &P) -> impl Future<Output = usize> + Send + 'a
+where
+	P: Serialize + ?Sized + Debug + 'a,
+{
+	self.keys_prefix::<Ignore, P>(prefix).count()
+}

src/database/map/keys.rs

@@ -0,0 +1,21 @@
+use conduit::{implement, Result};
+use futures::{Stream, StreamExt};
+use serde::Deserialize;
+
+use crate::{keyval, keyval::Key, stream};
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn keys<'a, K>(&'a self) -> impl Stream<Item = Result<Key<'_, K>>> + Send
+where
+	K: Deserialize<'a> + Send,
+{
+	self.raw_keys().map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn raw_keys(&self) -> impl Stream<Item = Result<Key<'_>>> + Send {
+	let opts = super::read_options_default();
+	stream::Keys::new(&self.db, &self.cf, opts, None)
+}

src/database/map/keys_from.rs

@@ -0,0 +1,49 @@
+use std::{convert::AsRef, fmt::Debug};
+
+use conduit::{implement, Result};
+use futures::{Stream, StreamExt};
+use serde::{Deserialize, Serialize};
+
+use crate::{keyval, keyval::Key, ser, stream};
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn keys_from<'a, K, P>(&'a self, from: &P) -> impl Stream<Item = Result<Key<'_, K>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+	K: Deserialize<'a> + Send,
+{
+	self.keys_raw_from(from)
+		.map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn keys_raw_from<P>(&self, from: &P) -> impl Stream<Item = Result<Key<'_>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+{
+	let key = ser::serialize_to_vec(from).expect("failed to serialize query key");
+	self.raw_keys_from(&key)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn keys_from_raw<'a, K, P>(&'a self, from: &P) -> impl Stream<Item = Result<Key<'_, K>>> + Send
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync,
+	K: Deserialize<'a> + Send,
+{
+	self.raw_keys_from(from)
+		.map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn raw_keys_from<P>(&self, from: &P) -> impl Stream<Item = Result<Key<'_>>> + Send
+where
+	P: AsRef<[u8]> + ?Sized + Debug,
+{
+	let opts = super::read_options_default();
+	stream::Keys::new(&self.db, &self.cf, opts, Some(from.as_ref()))
+}

src/database/map/keys_prefix.rs

@@ -0,0 +1,54 @@
+use std::{convert::AsRef, fmt::Debug};
+
+use conduit::{implement, Result};
+use futures::{
+	future,
+	stream::{Stream, StreamExt},
+	TryStreamExt,
+};
+use serde::{Deserialize, Serialize};
+
+use crate::{keyval, keyval::Key, ser};
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn keys_prefix<'a, K, P>(&'a self, prefix: &P) -> impl Stream<Item = Result<Key<'_, K>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+	K: Deserialize<'a> + Send,
+{
+	self.keys_raw_prefix(prefix)
+		.map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn keys_raw_prefix<P>(&self, prefix: &P) -> impl Stream<Item = Result<Key<'_>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+{
+	let key = ser::serialize_to_vec(prefix).expect("failed to serialize query key");
+	self.raw_keys_from(&key)
+		.try_take_while(move |k: &Key<'_>| future::ok(k.starts_with(&key)))
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn keys_prefix_raw<'a, K, P>(&'a self, prefix: &'a P) -> impl Stream<Item = Result<Key<'_, K>>> + Send + 'a
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
+	K: Deserialize<'a> + Send + 'a,
+{
+	self.raw_keys_prefix(prefix)
+		.map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn raw_keys_prefix<'a, P>(&'a self, prefix: &'a P) -> impl Stream<Item = Result<Key<'_>>> + Send + 'a
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
+{
+	self.raw_keys_from(prefix)
+		.try_take_while(|k: &Key<'_>| future::ok(k.starts_with(prefix.as_ref())))
+}

src/database/map/rev_keys.rs

@@ -0,0 +1,21 @@
+use conduit::{implement, Result};
+use futures::{Stream, StreamExt};
+use serde::Deserialize;
+
+use crate::{keyval, keyval::Key, stream};
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_keys<'a, K>(&'a self) -> impl Stream<Item = Result<Key<'_, K>>> + Send
+where
+	K: Deserialize<'a> + Send,
+{
+	self.rev_raw_keys().map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_raw_keys(&self) -> impl Stream<Item = Result<Key<'_>>> + Send {
+	let opts = super::read_options_default();
+	stream::KeysRev::new(&self.db, &self.cf, opts, None)
+}

src/database/map/rev_keys_from.rs

@@ -0,0 +1,49 @@
+use std::{convert::AsRef, fmt::Debug};
+
+use conduit::{implement, Result};
+use futures::{Stream, StreamExt};
+use serde::{Deserialize, Serialize};
+
+use crate::{keyval, keyval::Key, ser, stream};
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_keys_from<'a, K, P>(&'a self, from: &P) -> impl Stream<Item = Result<Key<'_, K>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+	K: Deserialize<'a> + Send,
+{
+	self.rev_keys_raw_from(from)
+		.map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_keys_raw_from<P>(&self, from: &P) -> impl Stream<Item = Result<Key<'_>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+{
+	let key = ser::serialize_to_vec(from).expect("failed to serialize query key");
+	self.rev_raw_keys_from(&key)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_keys_from_raw<'a, K, P>(&'a self, from: &P) -> impl Stream<Item = Result<Key<'_, K>>> + Send
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync,
+	K: Deserialize<'a> + Send,
+{
+	self.rev_raw_keys_from(from)
+		.map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_raw_keys_from<P>(&self, from: &P) -> impl Stream<Item = Result<Key<'_>>> + Send
+where
+	P: AsRef<[u8]> + ?Sized + Debug,
+{
+	let opts = super::read_options_default();
+	stream::KeysRev::new(&self.db, &self.cf, opts, Some(from.as_ref()))
+}

src/database/map/rev_keys_prefix.rs

@@ -0,0 +1,54 @@
+use std::{convert::AsRef, fmt::Debug};
+
+use conduit::{implement, Result};
+use futures::{
+	future,
+	stream::{Stream, StreamExt},
+	TryStreamExt,
+};
+use serde::{Deserialize, Serialize};
+
+use crate::{keyval, keyval::Key, ser};
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_keys_prefix<'a, K, P>(&'a self, prefix: &P) -> impl Stream<Item = Result<Key<'_, K>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+	K: Deserialize<'a> + Send,
+{
+	self.rev_keys_raw_prefix(prefix)
+		.map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_keys_raw_prefix<P>(&self, prefix: &P) -> impl Stream<Item = Result<Key<'_>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+{
+	let key = ser::serialize_to_vec(prefix).expect("failed to serialize query key");
+	self.rev_raw_keys_from(&key)
+		.try_take_while(move |k: &Key<'_>| future::ok(k.starts_with(&key)))
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_keys_prefix_raw<'a, K, P>(&'a self, prefix: &'a P) -> impl Stream<Item = Result<Key<'_, K>>> + Send + 'a
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
+	K: Deserialize<'a> + Send + 'a,
+{
+	self.rev_raw_keys_prefix(prefix)
+		.map(keyval::result_deserialize_key::<K>)
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_raw_keys_prefix<'a, P>(&'a self, prefix: &'a P) -> impl Stream<Item = Result<Key<'_>>> + Send + 'a
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
+{
+	self.rev_raw_keys_from(prefix)
+		.try_take_while(|k: &Key<'_>| future::ok(k.starts_with(prefix.as_ref())))
+}

src/database/map/rev_stream.rs

@@ -0,0 +1,29 @@
+use conduit::{implement, Result};
+use futures::stream::{Stream, StreamExt};
+use serde::Deserialize;
+
+use crate::{keyval, keyval::KeyVal, stream};
+
+/// Iterate key-value entries in the map from the end.
+///
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_stream<'a, K, V>(&'a self) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send
+where
+	K: Deserialize<'a> + Send,
+	V: Deserialize<'a> + Send,
+{
+	self.rev_raw_stream()
+		.map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map from the end.
+///
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_raw_stream(&self) -> impl Stream<Item = Result<KeyVal<'_>>> + Send {
+	let opts = super::read_options_default();
+	stream::ItemsRev::new(&self.db, &self.cf, opts, None)
+}

src/database/map/rev_stream_from.rs

@@ -0,0 +1,68 @@
+use std::{convert::AsRef, fmt::Debug};
+
+use conduit::{implement, Result};
+use futures::stream::{Stream, StreamExt};
+use serde::{Deserialize, Serialize};
+
+use crate::{keyval, keyval::KeyVal, ser, stream};
+
+/// Iterate key-value entries in the map starting from upper-bound.
+///
+/// - Query is serialized
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_stream_from<'a, K, V, P>(&'a self, from: &P) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+	K: Deserialize<'a> + Send,
+	V: Deserialize<'a> + Send,
+{
+	let key = ser::serialize_to_vec(from).expect("failed to serialize query key");
+	self.rev_stream_raw_from(&key)
+		.map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map starting from upper-bound.
+///
+/// - Query is serialized
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_stream_raw_from<P>(&self, from: &P) -> impl Stream<Item = Result<KeyVal<'_>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+{
+	let key = ser::serialize_to_vec(from).expect("failed to serialize query key");
+	self.rev_raw_stream_from(&key)
+}
+
+/// Iterate key-value entries in the map starting from upper-bound.
+///
+/// - Query is raw
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_stream_from_raw<'a, K, V, P>(&'a self, from: &P) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync,
+	K: Deserialize<'a> + Send,
+	V: Deserialize<'a> + Send,
+{
+	self.rev_raw_stream_from(from)
+		.map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map starting from upper-bound.
+///
+/// - Query is raw
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_raw_stream_from<P>(&self, from: &P) -> impl Stream<Item = Result<KeyVal<'_>>> + Send
+where
+	P: AsRef<[u8]> + ?Sized + Debug,
+{
+	let opts = super::read_options_default();
+	stream::ItemsRev::new(&self.db, &self.cf, opts, Some(from.as_ref()))
+}

src/database/map/rev_stream_prefix.rs

@@ -0,0 +1,74 @@
+use std::{convert::AsRef, fmt::Debug};
+
+use conduit::{implement, Result};
+use futures::{
+	future,
+	stream::{Stream, StreamExt},
+	TryStreamExt,
+};
+use serde::{Deserialize, Serialize};
+
+use crate::{keyval, keyval::KeyVal, ser};
+
+/// Iterate key-value entries in the map where the key matches a prefix.
+///
+/// - Query is serialized
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_stream_prefix<'a, K, V, P>(&'a self, prefix: &P) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+	K: Deserialize<'a> + Send,
+	V: Deserialize<'a> + Send,
+{
+	self.rev_stream_raw_prefix(prefix)
+		.map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map where the key matches a prefix.
+///
+/// - Query is serialized
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_stream_raw_prefix<P>(&self, prefix: &P) -> impl Stream<Item = Result<KeyVal<'_>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+{
+	let key = ser::serialize_to_vec(prefix).expect("failed to serialize query key");
+	self.rev_raw_stream_from(&key)
+		.try_take_while(move |(k, _): &KeyVal<'_>| future::ok(k.starts_with(&key)))
+}
+
+/// Iterate key-value entries in the map where the key matches a prefix.
+///
+/// - Query is raw
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_stream_prefix_raw<'a, K, V, P>(
+	&'a self, prefix: &'a P,
+) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send + 'a
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
+	K: Deserialize<'a> + Send + 'a,
+	V: Deserialize<'a> + Send + 'a,
+{
+	self.rev_raw_stream_prefix(prefix)
+		.map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map where the key matches a prefix.
+///
+/// - Query is raw
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn rev_raw_stream_prefix<'a, P>(&'a self, prefix: &'a P) -> impl Stream<Item = Result<KeyVal<'_>>> + Send + 'a
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
+{
+	self.rev_raw_stream_from(prefix)
+		.try_take_while(|(k, _): &KeyVal<'_>| future::ok(k.starts_with(prefix.as_ref())))
+}

src/database/map/stream.rs

@@ -0,0 +1,28 @@
+use conduit::{implement, Result};
+use futures::stream::{Stream, StreamExt};
+use serde::Deserialize;
+
+use crate::{keyval, keyval::KeyVal, stream};
+
+/// Iterate key-value entries in the map from the beginning.
+///
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn stream<'a, K, V>(&'a self) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send
+where
+	K: Deserialize<'a> + Send,
+	V: Deserialize<'a> + Send,
+{
+	self.raw_stream().map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map from the beginning.
+///
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn raw_stream(&self) -> impl Stream<Item = Result<KeyVal<'_>>> + Send {
+	let opts = super::read_options_default();
+	stream::Items::new(&self.db, &self.cf, opts, None)
+}

src/database/map/stream_from.rs

@@ -0,0 +1,68 @@
+use std::{convert::AsRef, fmt::Debug};
+
+use conduit::{implement, Result};
+use futures::stream::{Stream, StreamExt};
+use serde::{Deserialize, Serialize};
+
+use crate::{keyval, keyval::KeyVal, ser, stream};
+
+/// Iterate key-value entries in the map starting from lower-bound.
+///
+/// - Query is serialized
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn stream_from<'a, K, V, P>(&'a self, from: &P) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+	K: Deserialize<'a> + Send,
+	V: Deserialize<'a> + Send,
+{
+	let key = ser::serialize_to_vec(from).expect("failed to serialize query key");
+	self.stream_raw_from(&key)
+		.map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map starting from lower-bound.
+///
+/// - Query is serialized
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn stream_raw_from<P>(&self, from: &P) -> impl Stream<Item = Result<KeyVal<'_>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+{
+	let key = ser::serialize_to_vec(from).expect("failed to serialize query key");
+	self.raw_stream_from(&key)
+}
+
+/// Iterate key-value entries in the map starting from lower-bound.
+///
+/// - Query is raw
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn stream_from_raw<'a, K, V, P>(&'a self, from: &P) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync,
+	K: Deserialize<'a> + Send,
+	V: Deserialize<'a> + Send,
+{
+	self.raw_stream_from(from)
+		.map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map starting from lower-bound.
+///
+/// - Query is raw
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn raw_stream_from<P>(&self, from: &P) -> impl Stream<Item = Result<KeyVal<'_>>> + Send
+where
+	P: AsRef<[u8]> + ?Sized + Debug,
+{
+	let opts = super::read_options_default();
+	stream::Items::new(&self.db, &self.cf, opts, Some(from.as_ref()))
+}

src/database/map/stream_prefix.rs

@@ -0,0 +1,74 @@
+use std::{convert::AsRef, fmt::Debug};
+
+use conduit::{implement, Result};
+use futures::{
+	future,
+	stream::{Stream, StreamExt},
+	TryStreamExt,
+};
+use serde::{Deserialize, Serialize};
+
+use crate::{keyval, keyval::KeyVal, ser};
+
+/// Iterate key-value entries in the map where the key matches a prefix.
+///
+/// - Query is serialized
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn stream_prefix<'a, K, V, P>(&'a self, prefix: &P) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+	K: Deserialize<'a> + Send,
+	V: Deserialize<'a> + Send,
+{
+	self.stream_raw_prefix(prefix)
+		.map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map where the key matches a prefix.
+///
+/// - Query is serialized
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn stream_raw_prefix<P>(&self, prefix: &P) -> impl Stream<Item = Result<KeyVal<'_>>> + Send
+where
+	P: Serialize + ?Sized + Debug,
+{
+	let key = ser::serialize_to_vec(prefix).expect("failed to serialize query key");
+	self.raw_stream_from(&key)
+		.try_take_while(move |(k, _): &KeyVal<'_>| future::ok(k.starts_with(&key)))
+}
+
+/// Iterate key-value entries in the map where the key matches a prefix.
+///
+/// - Query is raw
+/// - Result is deserialized
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn stream_prefix_raw<'a, K, V, P>(
+	&'a self, prefix: &'a P,
+) -> impl Stream<Item = Result<KeyVal<'_, K, V>>> + Send + 'a
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
+	K: Deserialize<'a> + Send + 'a,
+	V: Deserialize<'a> + Send + 'a,
+{
+	self.raw_stream_prefix(prefix)
+		.map(keyval::result_deserialize::<K, V>)
+}
+
+/// Iterate key-value entries in the map where the key matches a prefix.
+///
+/// - Query is raw
+/// - Result is raw
+#[implement(super::Map)]
+#[tracing::instrument(skip(self), fields(%self), level = "trace")]
+pub fn raw_stream_prefix<'a, P>(&'a self, prefix: &'a P) -> impl Stream<Item = Result<KeyVal<'_>>> + Send + 'a
+where
+	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
+{
+	self.raw_stream_from(prefix)
+		.try_take_while(|(k, _): &KeyVal<'_>| future::ok(k.starts_with(prefix.as_ref())))
+}