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fixes and comments

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This commit is contained in:
pedrocarlo 2025-05-12 11:29:24 -03:00
parent b2615d7739
commit 72cc0fcdcb
2 changed files with 80 additions and 74 deletions
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18
core/storage/btree.rs
View file

@ -339,6 +339,8 @@ enum OverflowState {
Done,
}
/// Holds a Record or RowId, so that these can be transformed into a SeekKey to restore
/// cursor position to its previous location.
enum CursorContext {
TableRowId(u64),
@ -347,9 +349,11 @@ enum CursorContext {
IndexKeyRowId(ImmutableRecord),
}
// In the future, we may expand these general validity states
/// In the future, we may expand these general validity states
enum CursorValidState {
/// Cursor is pointing a to an existing location/cell in the Btree
Valid,
/// Cursor may be pointing to a non-existent location/cell. This can happen after balancing operations
RequireSeek,
}
@ -381,9 +385,9 @@ pub struct BTreeCursor {
pub index_key_sort_order: IndexKeySortOrder,
/// Maintain count of the number of records in the btree. Used for the `Count` opcode
count: usize,
/// Stores the last record that was seen.
/// Stores the cursor context before rebalancing so that a seek can be done later
context: Option<CursorContext>,
/// Store whether the Cursor is in a valid state
/// Store whether the Cursor is in a valid state. Meaning if it is pointing to a valid cell index or not
valid_state: CursorValidState,
}
@ -4385,12 +4389,12 @@ impl BTreeCursor {
}
/// If context is defined, restore it and set it None on success
fn restore_context(&mut self) -> Result<CursorResult<bool>> {
fn restore_context(&mut self) -> Result<CursorResult<()>> {
if self.context.is_none() || !matches!(self.valid_state, CursorValidState::RequireSeek) {
return Ok(CursorResult::Ok(false));
return Ok(CursorResult::Ok(()));
}
let ctx = self.context.as_ref().unwrap();
let res = match ctx {
let _ = match ctx {
CursorContext::TableRowId(rowid) => self.seek(SeekKey::TableRowId(*rowid), SeekOp::EQ),
CursorContext::IndexKeyRowId(record) => {
// TODO: see how to avoid clone here
@ -4400,7 +4404,7 @@ impl BTreeCursor {
}?;
self.context = None;
self.valid_state = CursorValidState::Valid;
Ok(res)
Ok(CursorResult::Ok(()))
}
}

136
core/translate/emitter.rs
View file

@ -848,80 +848,82 @@ fn emit_update_insns(
}
for (index, (idx_cursor_id, record_reg)) in plan.indexes_to_update.iter().zip(&index_cursors) {
if index.unique {
let num_cols = index.columns.len();
// allocate scratch registers for the index columns plus rowid
let idx_start_reg = program.alloc_registers(num_cols + 1);
if !index.unique {
continue;
}
let rowid_reg = beg;
let idx_cols_start_reg = beg + 1;
let num_cols = index.columns.len();
// allocate scratch registers for the index columns plus rowid
let idx_start_reg = program.alloc_registers(num_cols + 1);
// copy each index column from the table's column registers into these scratch regs
for (i, col) in index.columns.iter().enumerate() {
// copy from the table's column register over to the index's scratch register
let rowid_reg = beg;
let idx_cols_start_reg = beg + 1;
// copy each index column from the table's column registers into these scratch regs
for (i, col) in index.columns.iter().enumerate() {
// copy from the table's column register over to the index's scratch register
program.emit_insn(Insn::Copy {
src_reg: idx_cols_start_reg + col.pos_in_table,
dst_reg: idx_start_reg + i,
amount: 0,
});
}
// last register is the rowid
program.emit_insn(Insn::Copy {
src_reg: rowid_reg,
dst_reg: idx_start_reg + num_cols,
src_reg: idx_cols_start_reg + col.pos_in_table,
dst_reg: idx_start_reg + i,
amount: 0,
});
program.emit_insn(Insn::MakeRecord {
start_reg: idx_start_reg,
count: num_cols + 1,
dest_reg: *record_reg,
index_name: Some(index.name.clone()),
});
let constraint_check = program.allocate_label();
program.emit_insn(Insn::NoConflict {
cursor_id: *idx_cursor_id,
target_pc: constraint_check,
record_reg: idx_start_reg,
num_regs: num_cols,
});
let column_names = index.columns.iter().enumerate().fold(
String::with_capacity(50),
|mut accum, (idx, col)| {
if idx > 0 {
accum.push_str(", ");
}
accum.push_str(&table_ref.table.get_name());
accum.push('.');
accum.push_str(&col.name);
accum
},
);
let idx_rowid_reg = program.alloc_register();
program.emit_insn(Insn::IdxRowId {
cursor_id: *idx_cursor_id,
dest: idx_rowid_reg,
});
program.emit_insn(Insn::Eq {
lhs: rowid_reg,
rhs: idx_rowid_reg,
target_pc: constraint_check,
flags: CmpInsFlags::default(), // TODO: not sure what type of comparison flag is needed
});
program.emit_insn(Insn::Halt {
err_code: SQLITE_CONSTRAINT_PRIMARYKEY, // TODO: distinct between primary key and unique index for error code
description: column_names,
});
program.preassign_label_to_next_insn(constraint_check);
}
// last register is the rowid
program.emit_insn(Insn::Copy {
src_reg: rowid_reg,
dst_reg: idx_start_reg + num_cols,
amount: 0,
});
program.emit_insn(Insn::MakeRecord {
start_reg: idx_start_reg,
count: num_cols + 1,
dest_reg: *record_reg,
index_name: Some(index.name.clone()),
});
let constraint_check = program.allocate_label();
program.emit_insn(Insn::NoConflict {
cursor_id: *idx_cursor_id,
target_pc: constraint_check,
record_reg: idx_start_reg,
num_regs: num_cols,
});
let column_names = index.columns.iter().enumerate().fold(
String::with_capacity(50),
|mut accum, (idx, col)| {
if idx > 0 {
accum.push_str(", ");
}
accum.push_str(&table_ref.table.get_name());
accum.push('.');
accum.push_str(&col.name);
accum
},
);
let idx_rowid_reg = program.alloc_register();
program.emit_insn(Insn::IdxRowId {
cursor_id: *idx_cursor_id,
dest: idx_rowid_reg,
});
program.emit_insn(Insn::Eq {
lhs: rowid_reg,
rhs: idx_rowid_reg,
target_pc: constraint_check,
flags: CmpInsFlags::default(), // TODO: not sure what type of comparison flag is needed
});
program.emit_insn(Insn::Halt {
err_code: SQLITE_CONSTRAINT_PRIMARYKEY, // TODO: distinct between primary key and unique index for error code
description: column_names,
});
program.preassign_label_to_next_insn(constraint_check);
}
if let Some(btree_table) = table_ref.btree() {