prepare for merge

columnar/src/column/mod.rs

@@ -22,6 +22,9 @@ pub struct Column<T> {
 }
 
 impl<T: PartialOrd> Column<T> {
+    pub fn get_cardinality(&self) -> Cardinality {
+        self.idx.get_cardinality()
+    }
     pub fn num_rows(&self) -> RowId {
         match &self.idx {
             ColumnIndex::Full => self.values.num_vals() as u32,

columnar/src/columnar/merge.rs

@@ -1,9 +1,10 @@
 use std::collections::HashMap;
 use std::io;
 
+use super::writer::ColumnarSerializer;
 use crate::columnar::ColumnarReader;
 use crate::dynamic_column::DynamicColumn;
-use crate::ColumnType;
+use crate::{Cardinality, ColumnType};
 
 pub enum MergeDocOrder {
     /// Columnar tables are simply stacked one above the other.
@@ -19,20 +20,30 @@ pub enum MergeDocOrder {
 }
 
 pub fn merge_columnar(
-    _columnar_readers: &[ColumnarReader],
+    columnar_readers: &[ColumnarReader],
     mapping: MergeDocOrder,
-    _output: &mut impl io::Write,
+    output: &mut impl io::Write,
 ) -> io::Result<()> {
-    match mapping {
-        MergeDocOrder::Stack => {
-            // implement me :)
-            todo!();
-        }
-        MergeDocOrder::Complex(_) => {
-            // for later
-            todo!();
+    let mut serializer = ColumnarSerializer::new(output);
+
+    // TODO handle dictionary merge for Str/Bytes column
+    let field_name_to_group = group_columns_for_merge(columnar_readers)?;
+    for (column_name, category_to_columns) in field_name_to_group {
+        for (_category, columns_to_merge) in category_to_columns {
+            let column_type = columns_to_merge[0].column_type();
+            let mut column_serialzier =
+                serializer.serialize_column(column_name.as_bytes(), column_type);
+            merge_columns(
+                column_type,
+                &columns_to_merge,
+                &mapping,
+                &mut column_serialzier,
+            )?;
         }
     }
+    serializer.finalize()?;
+
+    Ok(())
 }
 
 /// Column types are grouped into different categories.
@@ -44,7 +55,7 @@ pub fn merge_columnar(
 /// See also [README.md].
 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
 #[repr(u8)]
-enum ColumnTypeCategory {
+pub enum ColumnTypeCategory {
     Bool,
     Str,
     Numerical,
@@ -68,8 +79,41 @@ impl From<ColumnType> for ColumnTypeCategory {
     }
 }
 
-fn collect_columns(
-    columnar_readers: &[&ColumnarReader],
+pub fn detect_cardinality(columns: &[DynamicColumn]) -> Cardinality {
+    if columns
+        .iter()
+        .any(|column| column.get_cardinality().is_multivalue())
+    {
+        return Cardinality::Multivalued;
+    }
+    if columns
+        .iter()
+        .any(|column| column.get_cardinality().is_optional())
+    {
+        return Cardinality::Optional;
+    }
+    Cardinality::Full
+}
+
+pub fn compute_num_docs(columns: &[DynamicColumn], mapping: &MergeDocOrder) -> usize {
+    // TODO handle deletes
+
+    0
+}
+
+pub fn merge_columns(
+    column_type: ColumnType,
+    columns: &[DynamicColumn],
+    mapping: &MergeDocOrder,
+    column_serializer: &mut impl io::Write,
+) -> io::Result<()> {
+    let cardinality = detect_cardinality(columns);
+
+    Ok(())
+}
+
+pub fn group_columns_for_merge(
+    columnar_readers: &[ColumnarReader],
 ) -> io::Result<HashMap<String, HashMap<ColumnTypeCategory, Vec<DynamicColumn>>>> {
     // Each column name may have multiple types of column associated.
     // For merging we are interested in the same column type category since they can be merged.
@@ -117,26 +161,20 @@ fn cast_to_common_numerical_column(columns: &[DynamicColumn]) -> Vec<DynamicColu
         .all(|column| column.column_type().numerical_type().is_some()));
     let coerce_to_i64: Vec<_> = columns
         .iter()
-        .map(|column| column.clone().coerce_to_i64())
+        .filter_map(|column| column.clone().coerce_to_i64())
         .collect();
 
-    if coerce_to_i64.iter().all(|column| column.is_some()) {
-        return coerce_to_i64
-            .into_iter()
-            .map(|column| column.unwrap())
-            .collect();
+    if coerce_to_i64.len() == columns.len() {
+        return coerce_to_i64;
     }
 
     let coerce_to_u64: Vec<_> = columns
         .iter()
-        .map(|column| column.clone().coerce_to_u64())
+        .filter_map(|column| column.clone().coerce_to_u64())
         .collect();
 
-    if coerce_to_u64.iter().all(|column| column.is_some()) {
-        return coerce_to_u64
-            .into_iter()
-            .map(|column| column.unwrap())
-            .collect();
+    if coerce_to_u64.len() == columns.len() {
+        return coerce_to_u64;
     }
 
     columns
@@ -183,7 +221,9 @@ mod tests {
             ColumnarReader::open(buffer).unwrap()
         };
 
-        let column_map = collect_columns(&[&columnar1, &columnar2, &columnar3]).unwrap();
+        let column_map =
+            group_columns_for_merge(&[columnar1.clone(), columnar2.clone(), columnar3.clone()])
+                .unwrap();
         assert_eq!(column_map.len(), 1);
         let cat_to_columns = column_map.get("numbers").unwrap();
         assert_eq!(cat_to_columns.len(), 1);
@@ -191,14 +231,14 @@ mod tests {
         let numerical = cat_to_columns.get(&ColumnTypeCategory::Numerical).unwrap();
         assert!(numerical.iter().all(|column| column.is_f64()));
 
-        let column_map = collect_columns(&[&columnar1, &columnar1]).unwrap();
+        let column_map = group_columns_for_merge(&[columnar1.clone(), columnar1.clone()]).unwrap();
         assert_eq!(column_map.len(), 1);
         let cat_to_columns = column_map.get("numbers").unwrap();
         assert_eq!(cat_to_columns.len(), 1);
         let numerical = cat_to_columns.get(&ColumnTypeCategory::Numerical).unwrap();
         assert!(numerical.iter().all(|column| column.is_i64()));
 
-        let column_map = collect_columns(&[&columnar2, &columnar2]).unwrap();
+        let column_map = group_columns_for_merge(&[columnar2.clone(), columnar2.clone()]).unwrap();
         assert_eq!(column_map.len(), 1);
         let cat_to_columns = column_map.get("numbers").unwrap();
         assert_eq!(cat_to_columns.len(), 1);

columnar/src/columnar/merge_index.rs

@@ -0,0 +1 @@
+

columnar/src/columnar/mod.rs

@@ -1,6 +1,7 @@
 mod column_type;
 mod format_version;
 mod merge;
+mod merge_index;
 mod reader;
 mod writer;
 

columnar/src/columnar/reader/mod.rs

@@ -13,6 +13,7 @@ fn io_invalid_data(msg: String) -> io::Error {
 
 /// The ColumnarReader makes it possible to access a set of columns
 /// associated to field names.
+#[derive(Clone)]
 pub struct ColumnarReader {
     column_dictionary: Dictionary<RangeSSTable>,
     column_data: FileSlice,

columnar/src/columnar/writer/mod.rs

@@ -8,7 +8,7 @@ use std::net::Ipv6Addr;
 
 use column_operation::ColumnOperation;
 use common::CountingWriter;
-use serializer::ColumnarSerializer;
+pub(crate) use serializer::ColumnarSerializer;
 use stacker::{Addr, ArenaHashMap, MemoryArena};
 
 use crate::column_index::SerializableColumnIndex;

columnar/src/dynamic_column.rs

@@ -8,7 +8,7 @@ use common::{HasLen, OwnedBytes};
 use crate::column::{BytesColumn, Column, StrColumn};
 use crate::column_values::{monotonic_map_column, StrictlyMonotonicFn};
 use crate::columnar::ColumnType;
-use crate::{DateTime, NumericalType};
+use crate::{Cardinality, DateTime, NumericalType};
 
 #[derive(Clone)]
 pub enum DynamicColumn {
@@ -23,6 +23,18 @@ pub enum DynamicColumn {
 }
 
 impl DynamicColumn {
+    pub fn get_cardinality(&self) -> Cardinality {
+        match self {
+            DynamicColumn::Bool(c) => c.get_cardinality(),
+            DynamicColumn::I64(c) => c.get_cardinality(),
+            DynamicColumn::U64(c) => c.get_cardinality(),
+            DynamicColumn::F64(c) => c.get_cardinality(),
+            DynamicColumn::IpAddr(c) => c.get_cardinality(),
+            DynamicColumn::DateTime(c) => c.get_cardinality(),
+            DynamicColumn::Bytes(c) => c.ords().get_cardinality(),
+            DynamicColumn::Str(c) => c.ords().get_cardinality(),
+        }
+    }
     pub fn column_type(&self) -> ColumnType {
         match self {
             DynamicColumn::Bool(_) => ColumnType::Bool,

columnar/src/lib.rs

@@ -62,6 +62,12 @@ pub enum Cardinality {
 }
 
 impl Cardinality {
+    pub fn is_optional(&self) -> bool {
+        matches!(self, Cardinality::Optional)
+    }
+    pub fn is_multivalue(&self) -> bool {
+        matches!(self, Cardinality::Multivalued)
+    }
     pub(crate) fn to_code(self) -> u8 {
         self as u8
     }

sstable/src/dictionary.rs

@@ -30,6 +30,7 @@ use crate::{BlockAddr, DeltaReader, Reader, SSTable, SSTableIndex, TermOrdinal};
 /// block boundary.
 ///
 /// (See also README.md)
+#[derive(Debug, Clone)]
 pub struct Dictionary<TSSTable: SSTable> {
     pub sstable_slice: FileSlice,
     pub sstable_index: SSTableIndex,

sstable/src/lib.rs

@@ -117,6 +117,7 @@ impl SSTable for MonotonicU64SSTable {
 /// `range_sstable[k1].end == range_sstable[k2].start`.
 ///
 /// The first range is not required to start at `0`.
+#[derive(Clone, Copy, Debug)]
 pub struct RangeSSTable;
 
 impl SSTable for RangeSSTable {

sstable/src/sstable_index.rs

@@ -5,7 +5,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::{common_prefix_len, SSTableDataCorruption, TermOrdinal};
 
-#[derive(Default, Debug, Serialize, Deserialize)]
+#[derive(Default, Debug, Clone, Serialize, Deserialize)]
 pub struct SSTableIndex {
     blocks: Vec<BlockMeta>,
 }
@@ -75,7 +75,7 @@ pub struct BlockAddr {
     pub first_ordinal: u64,
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub(crate) struct BlockMeta {
     /// Any byte string that is lexicographically greater or equal to
     /// the last key in the block,