split get_batch from get.rs; add aqry_batch

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

src/database/map/get_batch.rs

@@ -0,0 +1,57 @@
+use std::{convert::AsRef, fmt::Debug, sync::Arc};
+
+use conduit::{err, implement, utils::IterStream, Result};
+use futures::{Stream, StreamExt};
+use serde::Serialize;
+
+use crate::{util::map_err, Handle};
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self, keys), level = "trace")]
+pub fn aqry_batch<'b, 'a: 'b, const MAX: usize, I, K>(
+	self: &'a Arc<Self>, keys: I,
+) -> impl Stream<Item = Result<Handle<'b>>> + Send + 'a
+where
+	I: Iterator<Item = &'b K> + Send + 'a,
+	K: Serialize + ?Sized + Debug + 'b,
+{
+	keys.stream()
+		.map(move |key| self.aqry::<MAX, _>(&key))
+		.buffered(self.db.server.config.db_pool_workers.saturating_mul(2))
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self, keys), level = "trace")]
+pub fn get_batch<'a, I, K>(self: &'a Arc<Self>, keys: I) -> impl Stream<Item = Result<Handle<'_>>> + Send + 'a
+where
+	I: Iterator<Item = &'a K> + Debug + Send + 'a,
+	K: AsRef<[u8]> + Debug + Send + ?Sized + Sync + 'a,
+{
+	keys.stream()
+		.map(move |key| self.get(key))
+		.buffered(self.db.server.config.db_pool_workers.saturating_mul(2))
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self, keys), name = "batch_blocking", level = "trace")]
+pub(crate) fn get_batch_blocking<'a, I, K>(&self, keys: I) -> impl Iterator<Item = Result<Handle<'_>>> + Send
+where
+	I: Iterator<Item = &'a K> + ExactSizeIterator + Debug + Send,
+	K: AsRef<[u8]> + Debug + Send + ?Sized + Sync + 'a,
+{
+	// Optimization can be `true` if key vector is pre-sorted **by the column
+	// comparator**.
+	const SORTED: bool = false;
+
+	let read_options = &self.read_options;
+	self.db
+		.db
+		.batched_multi_get_cf_opt(&self.cf(), keys, SORTED, read_options)
+		.into_iter()
+		.map(|result| {
+			result
+				.map_err(map_err)?
+				.map(Handle::from)
+				.ok_or(err!(Request(NotFound("Not found in database"))))
+		})
+}