Add tuple info codec

systemxlabs · Feb 7, 2024 · e93bff7 · e93bff7
1 parent 2db2761
commit e93bff7
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Showing 3 changed files with 62 additions and 35 deletions.
diff --git a/bustubx/src/storage/codec/mod.rs b/bustubx/src/storage/codec/mod.rs
@@ -5,7 +5,7 @@ mod tuple;
 
 pub use common::CommonCodec;
 pub use scalar::ScalarValueCodec;
-pub use table_page::TablePageCodec;
+pub use table_page::{TablePageCodec, TablePageHeaderCodec, TablePageHeaderTupleInfoCodec};
 pub use tuple::TupleCodec;
 
 // data + consumed offset

diff --git a/bustubx/src/storage/codec/table_page.rs b/bustubx/src/storage/codec/table_page.rs
@@ -39,11 +39,7 @@ impl TablePageHeaderCodec {
         bytes.extend(CommonCodec::encode_u16(header.num_tuples));
         bytes.extend(CommonCodec::encode_u16(header.num_deleted_tuples));
         for tuple_info in header.tuple_infos.iter() {
-            bytes.extend(CommonCodec::encode_u16(tuple_info.offset));
-            bytes.extend(CommonCodec::encode_u16(tuple_info.size));
-            bytes.extend(CommonCodec::encode_u32(tuple_info.meta.insert_txn_id));
-            bytes.extend(CommonCodec::encode_u32(tuple_info.meta.delete_txn_id));
-            bytes.extend(CommonCodec::encode_bool(tuple_info.meta.is_deleted));
+            bytes.extend(TablePageHeaderTupleInfoCodec::encode(tuple_info));
         }
         bytes
     }
@@ -62,25 +58,9 @@ impl TablePageHeaderCodec {
 
         let mut tuple_infos = vec![];
         for _ in 0..num_tuples {
-            let (tuple_offset, offset) = CommonCodec::decode_u16(left_bytes)?;
+            let (tuple_info, offset) = TablePageHeaderTupleInfoCodec::decode(left_bytes)?;
             left_bytes = &left_bytes[offset..];
-            let (size, offset) = CommonCodec::decode_u16(left_bytes)?;
-            left_bytes = &left_bytes[offset..];
-            let (insert_txn_id, offset) = CommonCodec::decode_u32(left_bytes)?;
-            left_bytes = &left_bytes[offset..];
-            let (delete_txn_id, offset) = CommonCodec::decode_u32(left_bytes)?;
-            left_bytes = &left_bytes[offset..];
-            let (is_deleted, offset) = CommonCodec::decode_bool(left_bytes)?;
-            left_bytes = &left_bytes[offset..];
-            tuple_infos.push(TupleInfo {
-                offset: tuple_offset,
-                size,
-                meta: TupleMeta {
-                    insert_txn_id,
-                    delete_txn_id,
-                    is_deleted,
-                },
-            });
+            tuple_infos.push(tuple_info);
         }
         Ok((
             TablePageHeader {
@@ -94,6 +74,46 @@ impl TablePageHeaderCodec {
     }
 }
 
+pub struct TablePageHeaderTupleInfoCodec;
+
+impl TablePageHeaderTupleInfoCodec {
+    pub fn encode(tuple_info: &TupleInfo) -> Vec<u8> {
+        let mut bytes = Vec::new();
+        bytes.extend(CommonCodec::encode_u16(tuple_info.offset));
+        bytes.extend(CommonCodec::encode_u16(tuple_info.size));
+        bytes.extend(CommonCodec::encode_u32(tuple_info.meta.insert_txn_id));
+        bytes.extend(CommonCodec::encode_u32(tuple_info.meta.delete_txn_id));
+        bytes.extend(CommonCodec::encode_bool(tuple_info.meta.is_deleted));
+        bytes
+    }
+
+    pub fn decode(bytes: &[u8]) -> BustubxResult<DecodedData<TupleInfo>> {
+        let mut left_bytes = bytes;
+        let (tuple_offset, offset) = CommonCodec::decode_u16(left_bytes)?;
+        left_bytes = &left_bytes[offset..];
+        let (size, offset) = CommonCodec::decode_u16(left_bytes)?;
+        left_bytes = &left_bytes[offset..];
+        let (insert_txn_id, offset) = CommonCodec::decode_u32(left_bytes)?;
+        left_bytes = &left_bytes[offset..];
+        let (delete_txn_id, offset) = CommonCodec::decode_u32(left_bytes)?;
+        left_bytes = &left_bytes[offset..];
+        let (is_deleted, offset) = CommonCodec::decode_bool(left_bytes)?;
+        left_bytes = &left_bytes[offset..];
+        Ok((
+            TupleInfo {
+                offset: tuple_offset,
+                size,
+                meta: TupleMeta {
+                    insert_txn_id,
+                    delete_txn_id,
+                    is_deleted,
+                },
+            },
+            bytes.len() - left_bytes.len(),
+        ))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::buffer::INVALID_PAGE_ID;

diff --git a/bustubx/src/storage/table_page.rs b/bustubx/src/storage/table_page.rs
@@ -1,12 +1,21 @@
-use crate::buffer::{PageId, BUSTUBX_PAGE_SIZE, INVALID_PAGE_ID};
+use crate::buffer::{PageId, BUSTUBX_PAGE_SIZE};
 use crate::catalog::SchemaRef;
 use crate::common::rid::Rid;
-use crate::storage::codec::{CommonCodec, TupleCodec};
+use crate::storage::codec::{TablePageHeaderCodec, TablePageHeaderTupleInfoCodec, TupleCodec};
 
 use super::tuple::{Tuple, TupleMeta};
 
-pub const TABLE_PAGE_HEADER_SIZE: usize = 4 + 2 + 2;
-pub const TABLE_PAGE_TUPLE_INFO_SIZE: usize = 2 + 2 + (4 + 4 + 4);
+lazy_static::lazy_static! {
+    pub static ref EMPTY_TUPLE_INFO: TupleInfo = TupleInfo {
+        offset: 0,
+        size: 0,
+        meta: TupleMeta {
+            insert_txn_id: 0,
+            delete_txn_id: 0,
+            is_deleted: false,
+        }
+    };
+}
 
 /**
  * Slotted page format:
@@ -21,7 +30,7 @@ pub const TABLE_PAGE_TUPLE_INFO_SIZE: usize = 2 + 2 + (4 + 4 + 4);
  *  | NextPageId (4)| NumTuples(2) | NumDeletedTuples(2) |
  *  ----------------------------------------------------------------------------
  *  ----------------------------------------------------------------
- *  | Tuple_1 offset+size (4) + TupleMeta(12) | Tuple_2 offset+size (4) + TupleMeta(12)  | ... |
+ *  | Tuple_1 offset+size + TupleMeta | Tuple_2 offset+size + TupleMeta | ... |
  *  ----------------------------------------------------------------
  *
  */
@@ -42,7 +51,7 @@ impl TablePage {
                 next_page_id,
                 num_tuples: 0,
                 num_deleted_tuples: 0,
-                tuple_infos: Vec::with_capacity(BUSTUBX_PAGE_SIZE / TABLE_PAGE_TUPLE_INFO_SIZE),
+                tuple_infos: Vec::new(),
             },
             data: [0; BUSTUBX_PAGE_SIZE],
         }
@@ -69,9 +78,9 @@ impl TablePage {
 
         // Calculate the minimum valid tuple insertion offset, including the table page header size,
         // the total size of each tuple info (existing tuple infos and newly added tuple info).
-        let min_tuple_offset = TABLE_PAGE_HEADER_SIZE as u16
-            + (self.header.num_tuples as u16 + 1) * TABLE_PAGE_TUPLE_INFO_SIZE as u16;
-        if tuple_offset < min_tuple_offset {
+        let min_tuple_offset = TablePageHeaderCodec::encode(&self.header).len()
+            + TablePageHeaderTupleInfoCodec::encode(&EMPTY_TUPLE_INFO).len();
+        if (tuple_offset as usize) < min_tuple_offset {
             return None;
         }
 
@@ -173,9 +182,7 @@ pub struct TupleInfo {
 
 #[cfg(test)]
 mod tests {
-    use crate::buffer::BUSTUBX_PAGE_SIZE;
     use crate::catalog::{Column, DataType, Schema};
-    use crate::storage::codec::{TablePageCodec, TupleCodec};
     use crate::storage::Tuple;
     use std::sync::Arc;