Enable parallel iteration of records

lib/Cargo.toml

@@ -37,7 +37,7 @@ rand = "0.8.5"
 regex = "1.5.4"
 msgpack = { version = "1.0.0", package = "rmp-serde" }
 scrypt = "0.9.0"
-serde = { version = "1.0.136", features = ["derive"] }
+serde = { version = "1.0.136", features = ["derive", "rc"] }
 sha-1 = "0.10.0"
 sha2 = "0.10.2"
 slug = "0.1.4"

lib/src/cnf/mod.rs

@@ -1,3 +1,6 @@
+// Specifies how many concurrent jobs can be buffered in the worker channel.
+pub const MAX_CONCURRENT_TASKS: usize = 64;
+
 // Specifies how many subqueries will be processed recursively before the query fails.
 pub const MAX_RECURSIVE_QUERIES: usize = 16;
 

lib/src/dbs/channel.rs

@@ -11,7 +11,7 @@ use crate::sql::thing::Thing;
 use crate::sql::value::Value;
 use async_recursion::async_recursion;
 use nanoid::nanoid;
-use tokio::sync::mpsc::UnboundedSender;
+use tokio::sync::mpsc::Sender;
 
 impl Value {
 	pub async fn channel(
@@ -19,7 +19,7 @@ impl Value {
 		ctx: Runtime,
 		opt: Options,
 		txn: Transaction,
-		chn: UnboundedSender<(Option<Thing>, Value)>,
+		chn: Sender<(Option<Thing>, Value)>,
 	) -> Result<(), Error> {
 		if ctx.is_ok() {
 			match self {
@@ -27,7 +27,7 @@ impl Value {
 				Value::Model(v) => v.process(&ctx, &opt, &txn, &chn).await?,
 				Value::Thing(v) => v.process(&ctx, &opt, &txn, &chn).await?,
 				Value::Table(v) => v.process(&ctx, &opt, &txn, &chn).await?,
-				v => chn.send((None, v))?,
+				v => chn.send((None, v)).await?,
 			}
 		}
 		Ok(())
@@ -41,7 +41,7 @@ impl Array {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		chn: &UnboundedSender<(Option<Thing>, Value)>,
+		chn: &Sender<(Option<Thing>, Value)>,
 	) -> Result<(), Error> {
 		for v in self.value.into_iter() {
 			if ctx.is_ok() {
@@ -50,7 +50,7 @@ impl Array {
 					Value::Model(v) => v.process(ctx, opt, txn, chn).await?,
 					Value::Thing(v) => v.process(ctx, opt, txn, chn).await?,
 					Value::Table(v) => v.process(ctx, opt, txn, chn).await?,
-					v => chn.send((None, v))?,
+					v => chn.send((None, v)).await?,
 				}
 			}
 		}
@@ -64,7 +64,7 @@ impl Model {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		chn: &UnboundedSender<(Option<Thing>, Value)>,
+		chn: &Sender<(Option<Thing>, Value)>,
 	) -> Result<(), Error> {
 		if ctx.is_ok() {
 			if let Some(c) = self.count {
@@ -98,7 +98,7 @@ impl Thing {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		chn: &UnboundedSender<(Option<Thing>, Value)>,
+		chn: &Sender<(Option<Thing>, Value)>,
 	) -> Result<(), Error> {
 		Ok(())
 	}
@@ -110,7 +110,7 @@ impl Table {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		chn: &UnboundedSender<(Option<Thing>, Value)>,
+		chn: &Sender<(Option<Thing>, Value)>,
 	) -> Result<(), Error> {
 		Ok(())
 	}

lib/src/dbs/iterate.rs

@@ -21,7 +21,7 @@ impl Value {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		ite: &mut Iterator<'_>,
+		ite: &mut Iterator,
 	) -> Result<(), Error> {
 		if ctx.is_ok() {
 			match self {
@@ -44,7 +44,7 @@ impl Array {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		ite: &mut Iterator<'_>,
+		ite: &mut Iterator,
 	) -> Result<(), Error> {
 		for v in self.value.into_iter() {
 			if ctx.is_ok() {
@@ -67,7 +67,7 @@ impl Model {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		ite: &mut Iterator<'_>,
+		ite: &mut Iterator,
 	) -> Result<(), Error> {
 		if ctx.is_ok() {
 			if let Some(c) = self.count {
@@ -101,7 +101,7 @@ impl Thing {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		ite: &mut Iterator<'_>,
+		ite: &mut Iterator,
 	) -> Result<(), Error> {
 		Ok(())
 	}
@@ -113,7 +113,7 @@ impl Table {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		ite: &mut Iterator<'_>,
+		ite: &mut Iterator,
 	) -> Result<(), Error> {
 		Ok(())
 	}

lib/src/dbs/iterator.rs

@@ -1,4 +1,5 @@
 use crate::cnf::ID_CHARS;
+use crate::cnf::MAX_CONCURRENT_TASKS;
 use crate::ctx::Canceller;
 use crate::ctx::Context;
 use crate::dbs::Options;
@@ -7,11 +8,6 @@ use crate::dbs::Statement;
 use crate::dbs::Transaction;
 use crate::doc::Document;
 use crate::err::Error;
-use crate::sql::group::Groups;
-use crate::sql::limit::Limit;
-use crate::sql::order::Orders;
-use crate::sql::split::Splits;
-use crate::sql::start::Start;
 use crate::sql::statements::create::CreateStatement;
 use crate::sql::statements::delete::DeleteStatement;
 use crate::sql::statements::insert::InsertStatement;
@@ -21,99 +17,87 @@ use crate::sql::statements::update::UpdateStatement;
 use crate::sql::table::Table;
 use crate::sql::thing::Thing;
 use crate::sql::value::Value;
-use crate::sql::version::Version;
 use nanoid::nanoid;
 use std::mem;
+use std::sync::Arc;
 
 #[derive(Default)]
-pub struct Iterator<'a> {
+pub struct Iterator {
 	// Iterator status
 	run: Canceller,
+	// Iterator statement
+	stm: Statement,
+	// Iterator run option
+	parallel: bool,
 	// Iterator runtime error
 	error: Option<Error>,
 	// Iterator input values
 	readies: Vec<Value>,
 	// Iterator output results
 	results: Vec<Value>,
-	// Iterate options
-	pub parallel: bool,
-	// Underlying statement
-	pub stmt: Statement<'a>,
-	// Iterator options
-	pub split: Option<&'a Splits>,
-	pub group: Option<&'a Groups>,
-	pub order: Option<&'a Orders>,
-	pub limit: Option<&'a Limit>,
-	pub start: Option<&'a Start>,
-	pub version: Option<&'a Version>,
 }
 
-impl<'a> From<&'a SelectStatement> for Iterator<'a> {
-	fn from(v: &'a SelectStatement) -> Self {
+impl From<Arc<SelectStatement>> for Iterator {
+	fn from(v: Arc<SelectStatement>) -> Self {
 		Iterator {
-			stmt: Statement::from(v),
-			split: v.split.as_ref(),
-			group: v.group.as_ref(),
-			order: v.order.as_ref(),
-			limit: v.limit.as_ref(),
-			start: v.start.as_ref(),
 			parallel: v.parallel,
+			stm: Statement::from(v),
 			..Iterator::default()
 		}
 	}
 }
 
-impl<'a> From<&'a CreateStatement> for Iterator<'a> {
-	fn from(v: &'a CreateStatement) -> Self {
+impl From<Arc<CreateStatement>> for Iterator {
+	fn from(v: Arc<CreateStatement>) -> Self {
 		Iterator {
-			stmt: Statement::from(v),
 			parallel: v.parallel,
+			stm: Statement::from(v),
 			..Iterator::default()
 		}
 	}
 }
 
-impl<'a> From<&'a UpdateStatement> for Iterator<'a> {
-	fn from(v: &'a UpdateStatement) -> Self {
+impl From<Arc<UpdateStatement>> for Iterator {
+	fn from(v: Arc<UpdateStatement>) -> Self {
 		Iterator {
-			stmt: Statement::from(v),
 			parallel: v.parallel,
+			stm: Statement::from(v),
 			..Iterator::default()
 		}
 	}
 }
 
-impl<'a> From<&'a RelateStatement> for Iterator<'a> {
-	fn from(v: &'a RelateStatement) -> Self {
+impl From<Arc<RelateStatement>> for Iterator {
+	fn from(v: Arc<RelateStatement>) -> Self {
 		Iterator {
-			stmt: Statement::from(v),
 			parallel: v.parallel,
+			stm: Statement::from(v),
 			..Iterator::default()
 		}
 	}
 }
 
-impl<'a> From<&'a DeleteStatement> for Iterator<'a> {
-	fn from(v: &'a DeleteStatement) -> Self {
+impl From<Arc<DeleteStatement>> for Iterator {
+	fn from(v: Arc<DeleteStatement>) -> Self {
 		Iterator {
-			stmt: Statement::from(v),
 			parallel: v.parallel,
+			stm: Statement::from(v),
 			..Iterator::default()
 		}
 	}
 }
 
-impl<'a> From<&'a InsertStatement> for Iterator<'a> {
-	fn from(v: &'a InsertStatement) -> Self {
+impl From<Arc<InsertStatement>> for Iterator {
+	fn from(v: Arc<InsertStatement>) -> Self {
 		Iterator {
-			stmt: Statement::from(v),
 			parallel: v.parallel,
+			stm: Statement::from(v),
 			..Iterator::default()
 		}
 	}
 }
 
-impl<'a> Iterator<'a> {
+impl Iterator {
 	// Prepares a value for processing
 	pub fn prepare(&mut self, val: Value) {
 		self.readies.push(val)
@@ -135,7 +119,7 @@ impl<'a> Iterator<'a> {
 		txn: &Transaction,
 	) -> Result<Value, Error> {
 		// Log the statement
-		trace!("Iterating: {}", self.stmt);
+		trace!("Iterating: {}", self.stm);
 		// Enable context override
 		let mut ctx = Context::new(&ctx);
 		self.run = ctx.add_cancel();
@@ -162,35 +146,35 @@ impl<'a> Iterator<'a> {
 
 	#[inline]
 	fn output_split(&mut self, ctx: &Runtime, opt: &Options, txn: &Transaction) {
-		if self.split.is_some() {
+		if self.stm.split().is_some() {
 			// Ignore
 		}
 	}
 
 	#[inline]
 	fn output_group(&mut self, ctx: &Runtime, opt: &Options, txn: &Transaction) {
-		if self.group.is_some() {
+		if self.stm.group().is_some() {
 			// Ignore
 		}
 	}
 
 	#[inline]
 	fn output_order(&mut self, ctx: &Runtime, opt: &Options, txn: &Transaction) {
-		if self.order.is_some() {
+		if self.stm.order().is_some() {
 			// Ignore
 		}
 	}
 
 	#[inline]
 	fn output_start(&mut self, ctx: &Runtime, opt: &Options, txn: &Transaction) {
-		if let Some(v) = self.start {
+		if let Some(v) = self.stm.start() {
 			self.results = mem::take(&mut self.results).into_iter().skip(v.0).collect();
 		}
 	}
 
 	#[inline]
 	fn output_limit(&mut self, ctx: &Runtime, opt: &Options, txn: &Transaction) {
-		if let Some(v) = self.limit {
+		if let Some(v) = self.stm.limit() {
 			self.results = mem::take(&mut self.results).into_iter().take(v.0).collect();
 		}
 	}
@@ -230,20 +214,52 @@ impl<'a> Iterator<'a> {
 			// Run statements in parallel
 			true => {
 				let mut rcv = {
-					// Use multi producer channel
-					use tokio::sync::mpsc;
 					// Create an unbounded channel
-					let (chn, rcv) = mpsc::unbounded_channel();
+					let (chn, rx) = tokio::sync::mpsc::channel(MAX_CONCURRENT_TASKS);
 					// Process all prepared values
 					for v in mem::take(&mut self.readies) {
-						tokio::spawn(v.channel(ctx.clone(), opt.clone(), txn.clone(), chn.clone()));
+						if ctx.is_ok() {
+							tokio::spawn(v.channel(
+								ctx.clone(),
+								opt.clone(),
+								txn.clone(),
+								chn.clone(),
+							));
+						}
 					}
-					//
-					rcv
+					// Return the receiver
+					rx
+				};
+				let mut rcv = {
+					// Clone the send values
+					let ctx = ctx.clone();
+					let opt = opt.clone();
+					let txn = txn.clone();
+					let stm = self.stm.clone();
+					// Create an unbounded channel
+					let (chn, rx) = tokio::sync::mpsc::channel(MAX_CONCURRENT_TASKS);
+					// Process all received values
+					tokio::spawn(async move {
+						while let Some((k, v)) = rcv.recv().await {
+							if ctx.is_ok() {
+								tokio::spawn(Document::compute(
+									ctx.clone(),
+									opt.clone(),
+									txn.clone(),
+									chn.clone(),
+									stm.clone(),
+									k,
+									v,
+								));
+							}
+						}
+					});
+					// Return the receiver
+					rx
 				};
 				// Process all processed values
-				while let Some((k, v)) = rcv.recv().await {
-					self.process(&ctx, opt, txn, k, v).await;
+				while let Some(r) = rcv.recv().await {
+					self.result(r);
 				}
 				// Everything processed ok
 				Ok(())
@@ -267,13 +283,13 @@ impl<'a> Iterator<'a> {
 		// Setup a new document
 		let mut doc = Document::new(thg, &val);
 		// Process the document
-		let res = match self.stmt {
-			Statement::Select(_) => doc.select(ctx, opt, txn, &self.stmt).await,
-			Statement::Create(_) => doc.create(ctx, opt, txn, &self.stmt).await,
-			Statement::Update(_) => doc.update(ctx, opt, txn, &self.stmt).await,
-			Statement::Relate(_) => doc.relate(ctx, opt, txn, &self.stmt).await,
-			Statement::Delete(_) => doc.delete(ctx, opt, txn, &self.stmt).await,
-			Statement::Insert(_) => doc.insert(ctx, opt, txn, &self.stmt).await,
+		let res = match self.stm {
+			Statement::Select(_) => doc.select(ctx, opt, txn, &self.stm).await,
+			Statement::Create(_) => doc.create(ctx, opt, txn, &self.stm).await,
+			Statement::Update(_) => doc.update(ctx, opt, txn, &self.stm).await,
+			Statement::Relate(_) => doc.relate(ctx, opt, txn, &self.stm).await,
+			Statement::Delete(_) => doc.delete(ctx, opt, txn, &self.stm).await,
+			Statement::Insert(_) => doc.insert(ctx, opt, txn, &self.stm).await,
 			_ => unreachable!(),
 		};
 		// Process the result
@@ -295,10 +311,10 @@ impl<'a> Iterator<'a> {
 			Ok(v) => self.results.push(v),
 		}
 		// Check if we can exit
-		if self.group.is_none() {
-			if self.order.is_none() {
-				if let Some(l) = self.limit {
-					if let Some(s) = self.start {
+		if self.stm.group().is_none() {
+			if self.stm.order().is_none() {
+				if let Some(l) = self.stm.limit() {
+					if let Some(s) = self.stm.start() {
 						if self.results.len() == l.0 + s.0 {
 							self.run.cancel()
 						}

lib/src/dbs/statement.rs

@@ -1,65 +1,72 @@
+use crate::sql::group::Groups;
+use crate::sql::limit::Limit;
+use crate::sql::order::Orders;
+use crate::sql::split::Splits;
+use crate::sql::start::Start;
 use crate::sql::statements::create::CreateStatement;
 use crate::sql::statements::delete::DeleteStatement;
 use crate::sql::statements::insert::InsertStatement;
 use crate::sql::statements::relate::RelateStatement;
 use crate::sql::statements::select::SelectStatement;
 use crate::sql::statements::update::UpdateStatement;
+use crate::sql::version::Version;
 use std::fmt;
+use std::sync::Arc;
 
-#[derive(Debug)]
-pub enum Statement<'a> {
+#[derive(Clone, Debug)]
+pub enum Statement {
 	None,
-	Select(&'a SelectStatement),
-	Create(&'a CreateStatement),
-	Update(&'a UpdateStatement),
-	Relate(&'a RelateStatement),
-	Delete(&'a DeleteStatement),
-	Insert(&'a InsertStatement),
+	Select(Arc<SelectStatement>),
+	Create(Arc<CreateStatement>),
+	Update(Arc<UpdateStatement>),
+	Relate(Arc<RelateStatement>),
+	Delete(Arc<DeleteStatement>),
+	Insert(Arc<InsertStatement>),
 }
 
-impl Default for Statement<'_> {
+impl Default for Statement {
 	fn default() -> Self {
 		Statement::None
 	}
 }
 
-impl<'a> From<&'a SelectStatement> for Statement<'a> {
-	fn from(v: &'a SelectStatement) -> Self {
+impl From<Arc<SelectStatement>> for Statement {
+	fn from(v: Arc<SelectStatement>) -> Self {
 		Statement::Select(v)
 	}
 }
 
-impl<'a> From<&'a CreateStatement> for Statement<'a> {
-	fn from(v: &'a CreateStatement) -> Self {
+impl From<Arc<CreateStatement>> for Statement {
+	fn from(v: Arc<CreateStatement>) -> Self {
 		Statement::Create(v)
 	}
 }
 
-impl<'a> From<&'a UpdateStatement> for Statement<'a> {
-	fn from(v: &'a UpdateStatement) -> Self {
+impl From<Arc<UpdateStatement>> for Statement {
+	fn from(v: Arc<UpdateStatement>) -> Self {
 		Statement::Update(v)
 	}
 }
 
-impl<'a> From<&'a RelateStatement> for Statement<'a> {
-	fn from(v: &'a RelateStatement) -> Self {
+impl From<Arc<RelateStatement>> for Statement {
+	fn from(v: Arc<RelateStatement>) -> Self {
 		Statement::Relate(v)
 	}
 }
 
-impl<'a> From<&'a DeleteStatement> for Statement<'a> {
-	fn from(v: &'a DeleteStatement) -> Self {
+impl From<Arc<DeleteStatement>> for Statement {
+	fn from(v: Arc<DeleteStatement>) -> Self {
 		Statement::Delete(v)
 	}
 }
 
-impl<'a> From<&'a InsertStatement> for Statement<'a> {
-	fn from(v: &'a InsertStatement) -> Self {
+impl From<Arc<InsertStatement>> for Statement {
+	fn from(v: Arc<InsertStatement>) -> Self {
 		Statement::Insert(v)
 	}
 }
 
-impl<'a> fmt::Display for Statement<'a> {
+impl fmt::Display for Statement {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		match self {
 			Statement::Select(v) => write!(f, "{}", v),
@@ -72,3 +79,48 @@ impl<'a> fmt::Display for Statement<'a> {
 		}
 	}
 }
+
+impl Statement {
+	// Returns any SPLIT clause if specified
+	pub fn split<'a>(self: &'a Statement) -> Option<&'a Splits> {
+		match self {
+			Statement::Select(v) => v.split.as_ref(),
+			_ => None,
+		}
+	}
+	// Returns any GROUP clause if specified
+	pub fn group<'a>(self: &'a Statement) -> Option<&'a Groups> {
+		match self {
+			Statement::Select(v) => v.group.as_ref(),
+			_ => None,
+		}
+	}
+	// Returns any ORDER clause if specified
+	pub fn order<'a>(self: &'a Statement) -> Option<&'a Orders> {
+		match self {
+			Statement::Select(v) => v.order.as_ref(),
+			_ => None,
+		}
+	}
+	// Returns any START clause if specified
+	pub fn start<'a>(self: &'a Statement) -> Option<&'a Start> {
+		match self {
+			Statement::Select(v) => v.start.as_ref(),
+			_ => None,
+		}
+	}
+	// Returns any LIMIT clause if specified
+	pub fn limit<'a>(self: &'a Statement) -> Option<&'a Limit> {
+		match self {
+			Statement::Select(v) => v.limit.as_ref(),
+			_ => None,
+		}
+	}
+	// Returns any VERSION clause if specified
+	pub fn version<'a>(self: &'a Statement) -> Option<&'a Version> {
+		match self {
+			Statement::Select(v) => v.version.as_ref(),
+			_ => None,
+		}
+	}
+}

lib/src/doc/admit.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		_ctx: &Runtime,
 		_opt: &Options,
 		_txn: &Transaction,
-		stm: &Statement<'_>,
+		stm: &Statement,
 	) -> Result<(), Error> {
 		match self.id {
 			Some(_) => Ok(()),

lib/src/doc/allow.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		_ctx: &Runtime,
 		_opt: &Options,
 		_txn: &Transaction,
-		_stm: &Statement<'_>,
+		_stm: &Statement,
 	) -> Result<(), Error> {
 		Ok(())
 	}

lib/src/doc/check.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		stm: &Statement<'_>,
+		stm: &Statement,
 	) -> Result<(), Error> {
 		// Extract statement clause
 		let cond = match stm {

lib/src/doc/compute.rs

@@ -6,20 +6,22 @@ use crate::doc::Document;
 use crate::err::Error;
 use crate::sql::thing::Thing;
 use crate::sql::value::Value;
+use tokio::sync::mpsc::Sender;
 
 impl<'a> Document<'a> {
 	pub async fn compute(
 		ctx: Runtime,
 		opt: Options,
 		txn: Transaction,
-		stm: Statement<'_>,
+		chn: Sender<Result<Value, Error>>,
+		stm: Statement,
 		thg: Option<Thing>,
 		val: Value,
-	) -> Result<Value, Error> {
+	) -> Result<(), Error> {
 		// Setup a new document
 		let mut doc = Document::new(thg, &val);
 		// Process the statement
-		match stm {
+		let res = match stm {
 			Statement::Select(_) => doc.select(&ctx, &opt, &txn, &stm).await,
 			Statement::Create(_) => doc.create(&ctx, &opt, &txn, &stm).await,
 			Statement::Update(_) => doc.update(&ctx, &opt, &txn, &stm).await,
@@ -27,6 +29,10 @@ impl<'a> Document<'a> {
 			Statement::Delete(_) => doc.delete(&ctx, &opt, &txn, &stm).await,
 			Statement::Insert(_) => doc.insert(&ctx, &opt, &txn, &stm).await,
 			_ => unreachable!(),
-		}
+		};
+		// Send back the result
+		let _ = chn.send(res).await;
+		// Everything went ok
+		Ok(())
 	}
 }

lib/src/doc/create.rs

@@ -12,7 +12,7 @@ impl<'a> Document<'a> {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		stm: &Statement<'_>,
+		stm: &Statement,
 	) -> Result<Value, Error> {
 		// Check value type
 		self.admit(ctx, opt, txn, stm).await?;

lib/src/doc/delete.rs

@@ -12,7 +12,7 @@ impl<'a> Document<'a> {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		stm: &Statement<'_>,
+		stm: &Statement,
 	) -> Result<Value, Error> {
 		// Check value type
 		self.admit(ctx, opt, txn, stm).await?;

lib/src/doc/empty.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		_ctx: &Runtime,
 		_opt: &Options,
 		_txn: &Transaction,
-		_stm: &Statement<'_>,
+		_stm: &Statement,
 	) -> Result<(), Error> {
 		match self.id.is_some() && self.current.is_none() {
 			true => Err(Error::IgnoreError),

lib/src/doc/erase.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		_stm: &Statement<'_>,
+		_stm: &Statement,
 	) -> Result<(), Error> {
 		self.current.to_mut().clear(ctx, opt, txn).await
 	}

lib/src/doc/event.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		_ctx: &Runtime,
 		_opt: &Options,
 		_txn: &Transaction,
-		_stm: &Statement<'_>,
+		_stm: &Statement,
 	) -> Result<(), Error> {
 		Ok(())
 	}

lib/src/doc/index.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		_ctx: &Runtime,
 		_opt: &Options,
 		_txn: &Transaction,
-		_stm: &Statement<'_>,
+		_stm: &Statement,
 	) -> Result<(), Error> {
 		Ok(())
 	}

lib/src/doc/insert.rs

@@ -12,7 +12,7 @@ impl<'a> Document<'a> {
 		_ctx: &Runtime,
 		_opt: &Options,
 		_txn: &Transaction,
-		_stm: &Statement<'_>,
+		_stm: &Statement,
 	) -> Result<Value, Error> {
 		todo!()
 	}

lib/src/doc/lives.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		_ctx: &Runtime,
 		_opt: &Options,
 		_txn: &Transaction,
-		_stm: &Statement<'_>,
+		_stm: &Statement,
 	) -> Result<(), Error> {
 		Ok(())
 	}

lib/src/doc/merge.rs

@@ -14,7 +14,7 @@ impl<'a> Document<'a> {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		stm: &Statement<'_>,
+		stm: &Statement,
 	) -> Result<(), Error> {
 		// Get the ID reference
 		let id = self.id.as_ref();

lib/src/doc/pluck.rs

@@ -15,7 +15,7 @@ impl<'a> Document<'a> {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		stm: &Statement<'_>,
+		stm: &Statement,
 	) -> Result<Value, Error> {
 		// Extract statement clause
 		let expr = match stm {

lib/src/doc/relate.rs

@@ -12,7 +12,7 @@ impl<'a> Document<'a> {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		stm: &Statement<'_>,
+		stm: &Statement,
 	) -> Result<Value, Error> {
 		// Check value type
 		self.admit(ctx, opt, txn, stm).await?;

lib/src/doc/select.rs

@@ -12,7 +12,7 @@ impl<'a> Document<'a> {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		stm: &Statement<'_>,
+		stm: &Statement,
 	) -> Result<Value, Error> {
 		// Check if record exists
 		self.empty(ctx, opt, txn, stm).await?;

lib/src/doc/store.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		_ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		_stm: &Statement<'_>,
+		_stm: &Statement,
 	) -> Result<(), Error> {
 		Ok(())
 	}

lib/src/doc/table.rs

@@ -11,7 +11,7 @@ impl<'a> Document<'a> {
 		_ctx: &Runtime,
 		_opt: &Options,
 		_txn: &Transaction,
-		_stm: &Statement<'_>,
+		_stm: &Statement,
 	) -> Result<(), Error> {
 		Ok(())
 	}

lib/src/doc/update.rs

@@ -12,7 +12,7 @@ impl<'a> Document<'a> {
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
-		stm: &Statement<'_>,
+		stm: &Statement,
 	) -> Result<Value, Error> {
 		// Check value type
 		self.admit(ctx, opt, txn, stm).await?;

lib/src/sql/statement.rs

@@ -32,6 +32,7 @@ use nom::multi::separated_list1;
 use nom::sequence::delimited;
 use serde::{Deserialize, Serialize};
 use std::fmt;
+use std::sync::Arc;
 use std::time::Duration;
 
 #[derive(Clone, Debug, Default, Eq, PartialEq, Serialize, Deserialize)]
@@ -51,25 +52,25 @@ pub fn statements(i: &str) -> IResult<&str, Statements> {
 
 #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
 pub enum Statement {
-	Set(SetStatement),
-	Use(UseStatement),
-	Info(InfoStatement),
-	Live(LiveStatement),
-	Kill(KillStatement),
-	Begin(BeginStatement),
-	Cancel(CancelStatement),
-	Commit(CommitStatement),
-	Output(OutputStatement),
-	Ifelse(IfelseStatement),
-	Select(SelectStatement),
-	Create(CreateStatement),
-	Update(UpdateStatement),
-	Relate(RelateStatement),
-	Delete(DeleteStatement),
-	Insert(InsertStatement),
-	Define(DefineStatement),
-	Remove(RemoveStatement),
-	Option(OptionStatement),
+	Set(Arc<SetStatement>),
+	Use(Arc<UseStatement>),
+	Info(Arc<InfoStatement>),
+	Live(Arc<LiveStatement>),
+	Kill(Arc<KillStatement>),
+	Begin(Arc<BeginStatement>),
+	Cancel(Arc<CancelStatement>),
+	Commit(Arc<CommitStatement>),
+	Output(Arc<OutputStatement>),
+	Ifelse(Arc<IfelseStatement>),
+	Select(Arc<SelectStatement>),
+	Create(Arc<CreateStatement>),
+	Update(Arc<UpdateStatement>),
+	Relate(Arc<RelateStatement>),
+	Delete(Arc<DeleteStatement>),
+	Insert(Arc<InsertStatement>),
+	Define(Arc<DefineStatement>),
+	Remove(Arc<RemoveStatement>),
+	Option(Arc<OptionStatement>),
 }
 
 impl Statement {
@@ -162,25 +163,25 @@ pub fn statement(i: &str) -> IResult<&str, Statement> {
 	delimited(
 		mightbespace,
 		alt((
-			map(set, |v| Statement::Set(v)),
-			map(yuse, |v| Statement::Use(v)),
-			map(info, |v| Statement::Info(v)),
-			map(live, |v| Statement::Live(v)),
-			map(kill, |v| Statement::Kill(v)),
-			map(begin, |v| Statement::Begin(v)),
-			map(cancel, |v| Statement::Cancel(v)),
-			map(commit, |v| Statement::Commit(v)),
-			map(output, |v| Statement::Output(v)),
-			map(ifelse, |v| Statement::Ifelse(v)),
-			map(select, |v| Statement::Select(v)),
-			map(create, |v| Statement::Create(v)),
-			map(update, |v| Statement::Update(v)),
-			map(relate, |v| Statement::Relate(v)),
-			map(delete, |v| Statement::Delete(v)),
-			map(insert, |v| Statement::Insert(v)),
-			map(define, |v| Statement::Define(v)),
-			map(remove, |v| Statement::Remove(v)),
-			map(option, |v| Statement::Option(v)),
+			map(set, |v| Statement::Set(Arc::new(v))),
+			map(yuse, |v| Statement::Use(Arc::new(v))),
+			map(info, |v| Statement::Info(Arc::new(v))),
+			map(live, |v| Statement::Live(Arc::new(v))),
+			map(kill, |v| Statement::Kill(Arc::new(v))),
+			map(begin, |v| Statement::Begin(Arc::new(v))),
+			map(cancel, |v| Statement::Cancel(Arc::new(v))),
+			map(commit, |v| Statement::Commit(Arc::new(v))),
+			map(output, |v| Statement::Output(Arc::new(v))),
+			map(ifelse, |v| Statement::Ifelse(Arc::new(v))),
+			map(select, |v| Statement::Select(Arc::new(v))),
+			map(create, |v| Statement::Create(Arc::new(v))),
+			map(update, |v| Statement::Update(Arc::new(v))),
+			map(relate, |v| Statement::Relate(Arc::new(v))),
+			map(delete, |v| Statement::Delete(Arc::new(v))),
+			map(insert, |v| Statement::Insert(Arc::new(v))),
+			map(define, |v| Statement::Define(Arc::new(v))),
+			map(remove, |v| Statement::Remove(Arc::new(v))),
+			map(option, |v| Statement::Option(Arc::new(v))),
 		)),
 		mightbespace,
 	)(i)

lib/src/sql/statements/create.rs

@@ -16,6 +16,7 @@ use nom::combinator::opt;
 use nom::sequence::preceded;
 use serde::{Deserialize, Serialize};
 use std::fmt;
+use std::sync::Arc;
 
 #[derive(Clone, Debug, Default, Eq, PartialEq, Serialize, Deserialize, Store)]
 pub struct CreateStatement {
@@ -28,7 +29,7 @@ pub struct CreateStatement {
 
 impl CreateStatement {
 	pub async fn compute(
-		&self,
+		self: &Arc<Self>,
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
@@ -36,8 +37,10 @@ impl CreateStatement {
 	) -> Result<Value, Error> {
 		// Allowed to run?
 		opt.check(Level::No)?;
+		// Clone the statement
+		let s = Arc::clone(self);
 		// Create a new iterator
-		let mut i = Iterator::from(self);
+		let mut i = Iterator::from(s);
 		// Ensure futures are stored
 		let opt = &opt.futures(false);
 		// Loop over the create targets

lib/src/sql/statements/delete.rs

@@ -17,6 +17,7 @@ use nom::sequence::preceded;
 use nom::sequence::tuple;
 use serde::{Deserialize, Serialize};
 use std::fmt;
+use std::sync::Arc;
 
 #[derive(Clone, Debug, Default, Eq, PartialEq, Serialize, Deserialize, Store)]
 pub struct DeleteStatement {
@@ -29,7 +30,7 @@ pub struct DeleteStatement {
 
 impl DeleteStatement {
 	pub async fn compute(
-		&self,
+		self: &Arc<Self>,
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
@@ -37,8 +38,10 @@ impl DeleteStatement {
 	) -> Result<Value, Error> {
 		// Allowed to run?
 		opt.check(Level::No)?;
+		// Clone the statement
+		let s = Arc::clone(self);
 		// Create a new iterator
-		let mut i = Iterator::from(self);
+		let mut i = Iterator::from(s);
 		// Ensure futures are stored
 		let opt = &opt.futures(false);
 		// Loop over the delete targets

lib/src/sql/statements/insert.rs

@@ -18,6 +18,7 @@ use nom::combinator::opt;
 use nom::sequence::preceded;
 use serde::{Deserialize, Serialize};
 use std::fmt;
+use std::sync::Arc;
 
 #[derive(Clone, Debug, Default, Eq, PartialEq, Serialize, Deserialize, Store)]
 pub struct InsertStatement {
@@ -32,7 +33,7 @@ pub struct InsertStatement {
 
 impl InsertStatement {
 	pub async fn compute(
-		&self,
+		self: &Arc<Self>,
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
@@ -40,8 +41,10 @@ impl InsertStatement {
 	) -> Result<Value, Error> {
 		// Allowed to run?
 		opt.check(Level::No)?;
+		// Clone the statement
+		let s = Arc::clone(self);
 		// Create a new iterator
-		let mut i = Iterator::from(self);
+		let mut i = Iterator::from(s);
 		// Ensure futures are stored
 		let opt = &opt.futures(false);
 		// Parse the expression

lib/src/sql/statements/relate.rs

@@ -20,6 +20,7 @@ use nom::combinator::opt;
 use nom::sequence::preceded;
 use serde::{Deserialize, Serialize};
 use std::fmt;
+use std::sync::Arc;
 
 #[derive(Clone, Debug, Default, Eq, PartialEq, Serialize, Deserialize, Store)]
 pub struct RelateStatement {
@@ -35,7 +36,7 @@ pub struct RelateStatement {
 
 impl RelateStatement {
 	pub async fn compute(
-		&self,
+		self: &Arc<Self>,
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
@@ -43,8 +44,10 @@ impl RelateStatement {
 	) -> Result<Value, Error> {
 		// Allowed to run?
 		opt.check(Level::No)?;
+		// Clone the statement
+		let s = Arc::clone(self);
 		// Create a new iterator
-		let mut i = Iterator::from(self);
+		let mut i = Iterator::from(s);
 		// Ensure futures are stored
 		let opt = &opt.futures(false);
 		// Loop over the select targets

lib/src/sql/statements/select.rs

@@ -23,6 +23,7 @@ use nom::combinator::opt;
 use nom::sequence::preceded;
 use serde::{Deserialize, Serialize};
 use std::fmt;
+use std::sync::Arc;
 
 #[derive(Clone, Debug, Default, Eq, PartialEq, Serialize, Deserialize, Store)]
 pub struct SelectStatement {
@@ -57,7 +58,7 @@ impl SelectStatement {
 
 impl SelectStatement {
 	pub async fn compute(
-		&self,
+		self: &Arc<Self>,
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
@@ -65,8 +66,10 @@ impl SelectStatement {
 	) -> Result<Value, Error> {
 		// Allowed to run?
 		opt.check(Level::No)?;
+		// Clone the statement
+		let s = Arc::clone(self);
 		// Create a new iterator
-		let mut i = Iterator::from(self);
+		let mut i = Iterator::from(s);
 		// Ensure futures are processed
 		let opt = &opt.futures(true);
 		// Loop over the select targets

lib/src/sql/statements/update.rs

@@ -17,6 +17,7 @@ use nom::combinator::opt;
 use nom::sequence::preceded;
 use serde::{Deserialize, Serialize};
 use std::fmt;
+use std::sync::Arc;
 
 #[derive(Clone, Debug, Default, Eq, PartialEq, Serialize, Deserialize, Store)]
 pub struct UpdateStatement {
@@ -30,7 +31,7 @@ pub struct UpdateStatement {
 
 impl UpdateStatement {
 	pub async fn compute(
-		&self,
+		self: &Arc<Self>,
 		ctx: &Runtime,
 		opt: &Options,
 		txn: &Transaction,
@@ -38,8 +39,10 @@ impl UpdateStatement {
 	) -> Result<Value, Error> {
 		// Allowed to run?
 		opt.check(Level::No)?;
+		// Clone the statement
+		let s = Arc::clone(self);
 		// Create a new iterator
-		let mut i = Iterator::from(self);
+		let mut i = Iterator::from(s);
 		// Ensure futures are stored
 		let opt = &opt.futures(false);
 		// Loop over the update targets

lib/src/sql/subquery.rs

@@ -18,17 +18,18 @@ use nom::combinator::map;
 use serde::{Deserialize, Serialize};
 use std::cmp::Ordering;
 use std::fmt;
+use std::sync::Arc;
 
 #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
 pub enum Subquery {
 	Value(Value),
-	Select(SelectStatement),
-	Create(CreateStatement),
-	Update(UpdateStatement),
-	Delete(DeleteStatement),
-	Relate(RelateStatement),
-	Insert(InsertStatement),
 	Ifelse(IfelseStatement),
+	Select(Arc<SelectStatement>),
+	Create(Arc<CreateStatement>),
+	Update(Arc<UpdateStatement>),
+	Delete(Arc<DeleteStatement>),
+	Relate(Arc<RelateStatement>),
+	Insert(Arc<InsertStatement>),
 }
 
 impl PartialOrd for Subquery {
@@ -62,7 +63,7 @@ impl Subquery {
 				// Prepare context
 				let ctx = ctx.freeze();
 				// Process subquery
-				let res = v.compute(&ctx, &opt, txn, doc).await?;
+				let res = Arc::clone(v).compute(&ctx, &opt, txn, doc).await?;
 				// Process result
 				match v.limit() {
 					1 => match v.expr.single() {
@@ -88,7 +89,7 @@ impl Subquery {
 				// Prepare context
 				let ctx = ctx.freeze();
 				// Process subquery
-				match v.compute(&ctx, &opt, txn, doc).await? {
+				match Arc::clone(v).compute(&ctx, &opt, txn, doc).await? {
 					Value::Array(mut v) => match v.len() {
 						1 => Ok(v.value.remove(0)),
 						_ => Ok(v.into()),
@@ -109,7 +110,7 @@ impl Subquery {
 				// Prepare context
 				let ctx = ctx.freeze();
 				// Process subquery
-				match v.compute(&ctx, &opt, txn, doc).await? {
+				match Arc::clone(v).compute(&ctx, &opt, txn, doc).await? {
 					Value::Array(mut v) => match v.len() {
 						1 => Ok(v.value.remove(0)),
 						_ => Ok(v.into()),
@@ -130,7 +131,7 @@ impl Subquery {
 				// Prepare context
 				let ctx = ctx.freeze();
 				// Process subquery
-				match v.compute(&ctx, &opt, txn, doc).await? {
+				match Arc::clone(v).compute(&ctx, &opt, txn, doc).await? {
 					Value::Array(mut v) => match v.len() {
 						1 => Ok(v.value.remove(0)),
 						_ => Ok(v.into()),
@@ -151,7 +152,7 @@ impl Subquery {
 				// Prepare context
 				let ctx = ctx.freeze();
 				// Process subquery
-				match v.compute(&ctx, &opt, txn, doc).await? {
+				match Arc::clone(v).compute(&ctx, &opt, txn, doc).await? {
 					Value::Array(mut v) => match v.len() {
 						1 => Ok(v.value.remove(0)),
 						_ => Ok(v.into()),
@@ -172,7 +173,7 @@ impl Subquery {
 				// Prepare context
 				let ctx = ctx.freeze();
 				// Process subquery
-				match v.compute(&ctx, &opt, txn, doc).await? {
+				match Arc::clone(v).compute(&ctx, &opt, txn, doc).await? {
 					Value::Array(mut v) => match v.len() {
 						1 => Ok(v.value.remove(0)),
 						_ => Ok(v.into()),
@@ -211,12 +212,12 @@ fn subquery_ifelse(i: &str) -> IResult<&str, Subquery> {
 fn subquery_others(i: &str) -> IResult<&str, Subquery> {
 	let (i, _) = tag("(")(i)?;
 	let (i, v) = alt((
-		map(select, |v| Subquery::Select(v)),
-		map(create, |v| Subquery::Create(v)),
-		map(update, |v| Subquery::Update(v)),
-		map(delete, |v| Subquery::Delete(v)),
-		map(relate, |v| Subquery::Relate(v)),
-		map(insert, |v| Subquery::Insert(v)),
+		map(select, |v| Subquery::Select(Arc::new(v))),
+		map(create, |v| Subquery::Create(Arc::new(v))),
+		map(update, |v| Subquery::Update(Arc::new(v))),
+		map(delete, |v| Subquery::Delete(Arc::new(v))),
+		map(relate, |v| Subquery::Relate(Arc::new(v))),
+		map(insert, |v| Subquery::Insert(Arc::new(v))),
 		map(value, |v| Subquery::Value(v)),
 	))(i)?;
 	let (i, _) = tag(")")(i)?;

lib/src/sql/value/get.rs

@@ -9,6 +9,7 @@ use crate::sql::statements::select::SelectStatement;
 use crate::sql::value::{Value, Values};
 use async_recursion::async_recursion;
 use futures::future::try_join_all;
+use std::sync::Arc;
 
 impl Value {
 	#[cfg_attr(feature = "parallel", async_recursion)]
@@ -76,7 +77,8 @@ impl Value {
 							what: Values(vec![Value::Thing(v.clone())]),
 							..SelectStatement::default()
 						};
-						stm.compute(ctx, opt, txn, None)
+						Arc::new(stm)
+							.compute(ctx, opt, txn, None)
 							.await?
 							.first(ctx, opt, txn)
 							.await?