start chain join

src/db/iterator.rs

@@ -25,6 +25,16 @@ impl<'a> Debug for IteratorSlot<'a> {
     }
 }
 
+pub enum TableRowGetter {
+    Dummy,
+}
+
+impl Debug for TableRowGetter {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self { TableRowGetter::Dummy => write!(f, "DummyRowGetter") }
+    }
+}
+
 impl<'a> From<IteratorPtr<'a>> for IteratorSlot<'a> {
     fn from(it: IteratorPtr<'a>) -> Self {
         Self::Reified(it)
@@ -40,23 +50,45 @@ impl<'a> IteratorSlot<'a> {
     }
 }
 
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub enum ChainJoinKind {
+    NodeToFwdEdge,
+    NodeToBwdEdge,
+    FwdEdgeToNode,
+    BwdEdgeToNode
+}
+
 #[derive(Debug)]
 pub enum ExecPlan<'a> {
     NodeItPlan {
         it: IteratorSlot<'a>,
         info: TableInfo,
-        binding: String,
+        binding: Option<String>,
     },
     EdgeItPlan {
         it: IteratorSlot<'a>,
         info: TableInfo,
-        binding: String,
+        binding: Option<String>,
     },
     EdgeKeyOnlyBwdItPlan {
         it: IteratorSlot<'a>,
         info: TableInfo,
+        binding: Option<String>,
+    },
+    EdgeBwdItPlan {
+        it: IteratorSlot<'a>,
+        info: TableInfo,
+        binding: Option<String>,
+        getter: TableRowGetter,
+    },
+    ChainJoinItPlan {
+        left: Box<ExecPlan<'a>>,
+        right: TableRowGetter,
+        right_info: TableInfo,
+        kind: ChainJoinKind,
+        left_outer: bool,
+        right_outer: bool
     },
-    // EdgeBwdIt { it: IteratorPtr<'a>, sess: &'a Session<'a>, tid: u32 },
     // IndexIt {it: ..}
     KeySortedWithAssocItPlan {
         main: Box<ExecPlan<'a>>,
@@ -144,6 +176,12 @@ impl<'a> ExecPlan<'a> {
                     bags.get(0).unwrap().tuple_widths()
                 }
             }
+            ExecPlan::EdgeBwdItPlan { .. } => {
+                todo!()
+            }
+            ExecPlan::ChainJoinItPlan { .. } => {
+                todo!()
+            }
         }
     }
 }
@@ -181,7 +219,7 @@ impl<'a> ExecPlan<'a> {
 
                 Ok(Box::new(EdgeIterator { it, started: false, src_table_id: info.src_table_id.id }))
             }
-            ExecPlan::EdgeKeyOnlyBwdItPlan { it, info } => {
+            ExecPlan::EdgeKeyOnlyBwdItPlan { it, info, .. } => {
                 let it = it.try_get()?;
                 let mut prefix_tuple = OwnTuple::with_prefix(info.table_id.id as u32);
                 prefix_tuple.push_int(info.dst_table_id.id);
@@ -275,6 +313,12 @@ impl<'a> ExecPlan<'a> {
                 let bags = bags.iter().map(|i| i.iter()).collect::<Result<Vec<_>>>()?;
                 Ok(Box::new(BagsUnionIterator { bags, current: 0 }))
             }
+            ExecPlan::EdgeBwdItPlan { .. } => {
+                todo!()
+            }
+            ExecPlan::ChainJoinItPlan { .. } => {
+                todo!()
+            }
         }
     }
 }
@@ -1166,6 +1210,20 @@ mod tests {
 
             let duration = start.elapsed();
             println!("Time elapsed {:?}", duration);
+
+
+            let s = r##"from (e:Employee)-[hj:HasJob]->(j:Job)
+            where e.id == 110
+            select { fname: e.first_name, salary: hj.salary, job: j.title }"##;
+
+            let parsed = Parser::parse(Rule::relational_query, s)?.next().unwrap();
+            let plan = sess.query_to_plan(parsed)?;
+            println!("{:?}", plan);
+            let plan = sess.reify_output_plan(plan)?;
+            println!("{:?}", plan);
+            for val in plan.iter()? {
+                println!("{}", val?)
+            }
         }
         drop(engine);
         let _ = fs::remove_dir_all(db_path);

src/db/plan.rs

@@ -1,7 +1,7 @@
 use std::collections::btree_map::Entry;
 use crate::db::engine::Session;
-use crate::db::iterator::{ExecPlan, IteratorSlot, OutputItPlan};
-use crate::db::query::{FromEl, Selection};
+use crate::db::iterator::{ChainJoinKind, ExecPlan, IteratorSlot, OutputItPlan, TableRowGetter};
+use crate::db::query::{EdgeOrNodeEl, EdgeOrNodeKind, FromEl, Selection};
 use crate::db::table::{ColId, TableId, TableInfo};
 use crate::error::Result;
 use crate::parser::Rule;
@@ -67,8 +67,13 @@ impl<'a> Session<'a> {
     fn do_reify_intermediate_plan(&'a self, plan: ExecPlan<'a>) -> Result<(ExecPlan<'a>, AccessorMap)> {
         let res = match plan {
             ExecPlan::NodeItPlan { info, binding, .. } => {
-                let amap = self.node_accessor_map(&binding, &info);
-                let amap = convert_to_relative_accessor_map(amap);
+                let amap = match &binding {
+                    None => Default::default(),
+                    Some(binding) => {
+                        let amap = self.node_accessor_map(binding, &info);
+                        convert_to_relative_accessor_map(amap)
+                    }
+                };
                 let it = if info.table_id.in_root {
                     self.txn.iterator(true, &self.perm_cf)
                 } else {
@@ -83,8 +88,13 @@ impl<'a> Session<'a> {
                 (plan, amap)
             }
             ExecPlan::EdgeItPlan { info, binding, .. } => {
-                let amap = self.edge_accessor_map(&binding, &info);
-                let amap = convert_to_relative_accessor_map(amap);
+                let amap = match &binding {
+                    None => Default::default(),
+                    Some(binding) => {
+                        let amap = self.edge_accessor_map(&binding, &info);
+                        convert_to_relative_accessor_map(amap)
+                    }
+                };
                 let it = if info.table_id.in_root {
                     self.txn.iterator(true, &self.perm_cf)
                 } else {
@@ -98,6 +108,9 @@ impl<'a> Session<'a> {
                 };
                 (plan, amap)
             }
+            ExecPlan::EdgeBwdItPlan { .. } => {
+                todo!()
+            }
             ExecPlan::EdgeKeyOnlyBwdItPlan { .. } => todo!(),
             ExecPlan::KeySortedWithAssocItPlan { .. } => todo!(),
             ExecPlan::CartesianProdItPlan { left, right } => {
@@ -106,7 +119,7 @@ impl<'a> Session<'a> {
                 let r_map = shift_accessor_map(r_map, l_plan.tuple_widths());
                 let plan = ExecPlan::CartesianProdItPlan {
                     left: l_plan.into(),
-                    right: r_plan.into()
+                    right: r_plan.into(),
                 };
                 (plan, merge_accessor_map(l_map, r_map))
             }
@@ -141,6 +154,9 @@ impl<'a> Session<'a> {
                 (plan, amap)
             }
             ExecPlan::BagsUnionIt { .. } => todo!(),
+            ExecPlan::ChainJoinItPlan { .. } => {
+                todo!()
+            }
         };
         Ok(res)
     }
@@ -187,20 +203,70 @@ impl<'a> Session<'a> {
                             Ok(ExecPlan::NodeItPlan {
                                 it: IteratorSlot::Dummy,
                                 info: el.info,
-                                binding: el.binding,
+                                binding: Some(el.binding),
                             })
                         }
                         DataKind::Edge => {
                             Ok(ExecPlan::EdgeItPlan {
                                 it: IteratorSlot::Dummy,
                                 info: el.info,
-                                binding: el.binding,
+                                binding: Some(el.binding),
                             })
                         }
                         _ => Err(LogicError("Wrong type for table binding".to_string()))
                     }
                 }
-                FromEl::Chain(_) => todo!(),
+                FromEl::Chain(ch) => {
+                    let mut it = ch.into_iter();
+                    let nxt = it.next().ok_or_else(|| LogicError("Empty chain not allowed".to_string()))?;
+                    let mut prev_kind = nxt.kind;
+                    let mut prev_left_outer = nxt.left_outer_marker;
+                    let mut plan = match prev_kind {
+                        EdgeOrNodeKind::Node => {
+                            ExecPlan::NodeItPlan {
+                                it: IteratorSlot::Dummy,
+                                info: nxt.info,
+                                binding: nxt.binding,
+                            }
+                        }
+                        EdgeOrNodeKind::FwdEdge => {
+                            ExecPlan::EdgeItPlan {
+                                it: IteratorSlot::Dummy,
+                                info: nxt.info,
+                                binding: nxt.binding,
+                            }
+                        }
+                        EdgeOrNodeKind::BwdEdge => {
+                            ExecPlan::EdgeBwdItPlan {
+                                it: IteratorSlot::Dummy,
+                                info: nxt.info,
+                                binding: nxt.binding,
+                                getter: TableRowGetter::Dummy
+                            }
+                        }
+                    };
+                    for el in it {
+                        plan = ExecPlan::ChainJoinItPlan {
+                            left: plan.into(),
+                            right: TableRowGetter::Dummy,
+                            right_info: el.info,
+                            kind: match (prev_kind, el.kind) {
+                                (EdgeOrNodeKind::Node, EdgeOrNodeKind::FwdEdge) => ChainJoinKind::NodeToFwdEdge,
+                                (EdgeOrNodeKind::Node, EdgeOrNodeKind::BwdEdge) => ChainJoinKind::NodeToBwdEdge,
+                                (EdgeOrNodeKind::FwdEdge, EdgeOrNodeKind::Node) => ChainJoinKind::FwdEdgeToNode,
+                                (EdgeOrNodeKind::BwdEdge, EdgeOrNodeKind::Node) => ChainJoinKind::BwdEdgeToNode,
+                                _ => unreachable!()
+                            },
+                            left_outer: prev_left_outer,
+                            right_outer: el.right_outer_marker
+                        };
+
+                        prev_kind = el.kind;
+                        prev_left_outer = el.left_outer_marker;
+                    }
+                    println!("{:#?}", plan);
+                    Ok(plan)
+                }
             };
         let mut from_data = from_data.into_iter();
         let fst = from_data.next().ok_or_else(||
@@ -210,7 +276,7 @@ impl<'a> Session<'a> {
             let nxt = convert_el(nxt)?;
             res = ExecPlan::CartesianProdItPlan {
                 left: res.into(),
-                right: nxt.into()
+                right: nxt.into(),
             };
         }
         Ok(res)
@@ -321,7 +387,7 @@ impl<'a> Session<'a> {
                 dst_key_typing: vec![],
                 associates: vec![],
             },
-            binding: "".to_string(),
+            binding: None,
         }
     }
 }

src/db/query.rs

@@ -22,7 +22,7 @@ pub struct SimpleFromEl {
     pub info: TableInfo,
 }
 
-#[derive(Debug, Eq, PartialEq, Clone)]
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum EdgeOrNodeKind {
     FwdEdge,
     BwdEdge,