Files
turso/core/translate/update.rs
Jussi Saurio bc80ac1754 require &mut ProgramBuilder argument in optimize_plan()
this will be used for ephemeral plan construction for UPDATE in
a later commit.
2025-10-14 12:18:13 +03:00

410 lines
16 KiB
Rust

use std::collections::{HashMap, HashSet};
use std::sync::Arc;
use crate::schema::ROWID_SENTINEL;
use crate::translate::emitter::Resolver;
use crate::translate::expr::{
bind_and_rewrite_expr, walk_expr, BindingBehavior, ParamState, WalkControl,
};
use crate::translate::plan::{Operation, Scan};
use crate::translate::planner::{parse_limit, ROWID_STRS};
use crate::{
bail_parse_error,
schema::{Schema, Table},
util::normalize_ident,
vdbe::builder::{ProgramBuilder, ProgramBuilderOpts},
};
use turso_parser::ast::{self, Expr, Indexed, SortOrder};
use super::emitter::emit_program;
use super::expr::process_returning_clause;
use super::optimizer::optimize_plan;
use super::plan::{
ColumnUsedMask, IterationDirection, JoinedTable, Plan, TableReferences, UpdatePlan,
};
use super::planner::parse_where;
/*
* Update is simple. By default we scan the table, and for each row, we check the WHERE
* clause. If it evaluates to true, we build the new record with the updated value and insert.
*
* EXAMPLE:
*
sqlite> explain update t set a = 100 where b = 5;
addr opcode p1 p2 p3 p4 p5 comment
---- ------------- ---- ---- ---- ------------- -- -------------
0 Init 0 16 0 0 Start at 16
1 Null 0 1 2 0 r[1..2]=NULL
2 Noop 1 0 1 0
3 OpenWrite 0 2 0 3 0 root=2 iDb=0; t
4 Rewind 0 15 0 0
5 Column 0 1 6 0 r[6]= cursor 0 column 1
6 Ne 7 14 6 BINARY-8 81 if r[6]!=r[7] goto 14
7 Rowid 0 2 0 0 r[2]= rowid of 0
8 IsNull 2 15 0 0 if r[2]==NULL goto 15
9 Integer 100 3 0 0 r[3]=100
10 Column 0 1 4 0 r[4]= cursor 0 column 1
11 Column 0 2 5 0 r[5]= cursor 0 column 2
12 MakeRecord 3 3 1 0 r[1]=mkrec(r[3..5])
13 Insert 0 1 2 t 7 intkey=r[2] data=r[1]
14 Next 0 5 0 1
15 Halt 0 0 0 0
16 Transaction 0 1 1 0 1 usesStmtJournal=0
17 Integer 5 7 0 0 r[7]=5
18 Goto 0 1 0 0
*/
pub fn translate_update(
body: &mut ast::Update,
resolver: &Resolver,
mut program: ProgramBuilder,
connection: &Arc<crate::Connection>,
) -> crate::Result<ProgramBuilder> {
let mut plan = prepare_update_plan(&mut program, resolver.schema, body, connection, false)?;
optimize_plan(&mut program, &mut plan, resolver.schema)?;
let opts = ProgramBuilderOpts {
num_cursors: 1,
approx_num_insns: 20,
approx_num_labels: 4,
};
program.extend(&opts);
emit_program(connection, resolver, &mut program, plan, |_| {})?;
Ok(program)
}
pub fn translate_update_for_schema_change(
body: &mut ast::Update,
resolver: &Resolver,
mut program: ProgramBuilder,
connection: &Arc<crate::Connection>,
ddl_query: &str,
after: impl FnOnce(&mut ProgramBuilder),
) -> crate::Result<ProgramBuilder> {
let mut plan = prepare_update_plan(&mut program, resolver.schema, body, connection, true)?;
if let Plan::Update(plan) = &mut plan {
if program.capture_data_changes_mode().has_updates() {
plan.cdc_update_alter_statement = Some(ddl_query.to_string());
}
}
optimize_plan(&mut program, &mut plan, resolver.schema)?;
let opts = ProgramBuilderOpts {
num_cursors: 1,
approx_num_insns: 20,
approx_num_labels: 4,
};
program.extend(&opts);
emit_program(connection, resolver, &mut program, plan, after)?;
Ok(program)
}
pub fn prepare_update_plan(
program: &mut ProgramBuilder,
schema: &Schema,
body: &mut ast::Update,
connection: &Arc<crate::Connection>,
is_internal_schema_change: bool,
) -> crate::Result<Plan> {
if body.with.is_some() {
bail_parse_error!("WITH clause is not supported in UPDATE");
}
if body.or_conflict.is_some() {
bail_parse_error!("ON CONFLICT clause is not supported in UPDATE");
}
if body.from.is_some() {
bail_parse_error!("FROM clause is not supported in UPDATE");
}
if body
.indexed
.as_ref()
.is_some_and(|i| matches!(i, Indexed::IndexedBy(_)))
{
bail_parse_error!("INDEXED BY clause is not supported in UPDATE");
}
if !body.order_by.is_empty() {
bail_parse_error!("ORDER BY is not supported in UPDATE");
}
let table_name = &body.tbl_name.name;
// Check if this is a system table that should be protected from direct writes
// Skip this check for internal schema change operations (like ALTER TABLE)
if !is_internal_schema_change && crate::schema::is_system_table(table_name.as_str()) {
bail_parse_error!("table {} may not be modified", table_name);
}
if schema.table_has_indexes(&table_name.to_string()) && !schema.indexes_enabled() {
// Let's disable altering a table with indices altogether instead of checking column by
// column to be extra safe.
bail_parse_error!(
"UPDATE table disabled for table with indexes is disabled. Omit the `--experimental-indexes=false` flag to enable this feature."
);
}
let table = match schema.get_table(table_name.as_str()) {
Some(table) => table,
None => bail_parse_error!("Parse error: no such table: {}", table_name),
};
// Check if this is a materialized view
if schema.is_materialized_view(table_name.as_str()) {
bail_parse_error!("cannot modify materialized view {}", table_name);
}
// Check if this table has any incompatible dependent views
let incompatible_views = schema.has_incompatible_dependent_views(table_name.as_str());
if !incompatible_views.is_empty() {
use crate::incremental::compiler::DBSP_CIRCUIT_VERSION;
bail_parse_error!(
"Cannot UPDATE table '{}' because it has incompatible dependent materialized view(s): {}. \n\
These views were created with a different DBSP version than the current version ({}). \n\
Please DROP and recreate the view(s) before modifying this table.",
table_name,
incompatible_views.join(", "),
DBSP_CIRCUIT_VERSION
);
}
let table_name = table.get_name();
let iter_dir = body
.order_by
.first()
.and_then(|ob| {
ob.order.map(|o| match o {
SortOrder::Asc => IterationDirection::Forwards,
SortOrder::Desc => IterationDirection::Backwards,
})
})
.unwrap_or(IterationDirection::Forwards);
let joined_tables = vec![JoinedTable {
table: match table.as_ref() {
Table::Virtual(vtab) => Table::Virtual(vtab.clone()),
Table::BTree(btree_table) => Table::BTree(btree_table.clone()),
_ => unreachable!(),
},
identifier: body.tbl_name.alias.as_ref().map_or_else(
|| table_name.to_string(),
|alias| alias.as_str().to_string(),
),
internal_id: program.table_reference_counter.next(),
op: build_scan_op(&table, iter_dir),
join_info: None,
col_used_mask: ColumnUsedMask::default(),
database_id: 0,
}];
let mut table_references = TableReferences::new(joined_tables, vec![]);
let column_lookup: HashMap<String, usize> = table
.columns()
.iter()
.enumerate()
.filter_map(|(i, col)| col.name.as_ref().map(|name| (name.to_lowercase(), i)))
.collect();
let mut set_clauses = Vec::with_capacity(body.sets.len());
// Process each SET assignment and map column names to expressions
// e.g the statement `SET x = 1, y = 2, z = 3` has 3 set assigments
for set in &mut body.sets {
bind_and_rewrite_expr(
&mut set.expr,
Some(&mut table_references),
None,
connection,
&mut program.param_ctx,
BindingBehavior::ResultColumnsNotAllowed,
)?;
let values = match set.expr.as_ref() {
Expr::Parenthesized(vals) => vals.clone(),
expr => vec![expr.clone().into()],
};
if set.col_names.len() != values.len() {
bail_parse_error!(
"{} columns assigned {} values",
set.col_names.len(),
values.len()
);
}
for (col_name, expr) in set.col_names.iter().zip(values.iter()) {
let ident = normalize_ident(col_name.as_str());
let col_index = match column_lookup.get(&ident) {
Some(idx) => *idx,
None => {
// Check if this is the 'rowid' keyword
if ROWID_STRS.iter().any(|s| s.eq_ignore_ascii_case(&ident)) {
// Find the rowid alias column if it exists
if let Some((idx, _col)) = table
.columns()
.iter()
.enumerate()
.find(|(_i, c)| c.is_rowid_alias)
{
// Use the rowid alias column index
match set_clauses.iter_mut().find(|(i, _)| i == &idx) {
Some((_, existing_expr)) => *existing_expr = expr.clone(),
None => set_clauses.push((idx, expr.clone())),
}
idx
} else {
// No rowid alias, use sentinel value for actual rowid
match set_clauses.iter_mut().find(|(i, _)| *i == ROWID_SENTINEL) {
Some((_, existing_expr)) => *existing_expr = expr.clone(),
None => set_clauses.push((ROWID_SENTINEL, expr.clone())),
}
ROWID_SENTINEL
}
} else {
crate::bail_parse_error!("no such column: {}.{}", table_name, col_name);
}
}
};
match set_clauses.iter_mut().find(|(idx, _)| *idx == col_index) {
Some((_, existing_expr)) => *existing_expr = expr.clone(),
None => set_clauses.push((col_index, expr.clone())),
}
}
}
let (result_columns, _table_references) = process_returning_clause(
&mut body.returning,
&table,
body.tbl_name.name.as_str(),
program,
connection,
)?;
let order_by = body
.order_by
.iter_mut()
.map(|o| {
let _ = bind_and_rewrite_expr(
&mut o.expr,
Some(&mut table_references),
Some(&result_columns),
connection,
&mut program.param_ctx,
BindingBehavior::ResultColumnsNotAllowed,
);
(o.expr.clone(), o.order.unwrap_or(SortOrder::Asc))
})
.collect();
// Sqlite determines we should create an ephemeral table if we do not have a FROM clause
// Difficult to say what items from the plan can be checked for this so currently just checking if a RowId Alias is referenced
// https://github.com/sqlite/sqlite/blob/master/src/update.c#L395
// https://github.com/sqlite/sqlite/blob/master/src/update.c#L670
let columns = table.columns();
let mut where_clause = vec![];
// Parse the WHERE clause
parse_where(
body.where_clause.as_deref(),
&mut table_references,
Some(&result_columns),
&mut where_clause,
connection,
&mut program.param_ctx,
)?;
// Parse the LIMIT/OFFSET clause
let (limit, offset) = body.limit.as_mut().map_or(Ok((None, None)), |l| {
parse_limit(l, connection, &mut program.param_ctx)
})?;
// Check what indexes will need to be updated by checking set_clauses and see
// if a column is contained in an index.
let indexes = schema.get_indices(table_name);
let updated_cols: HashSet<usize> = set_clauses.iter().map(|(i, _)| *i).collect();
let rowid_alias_used = set_clauses
.iter()
.any(|(idx, _)| *idx == ROWID_SENTINEL || columns[*idx].is_rowid_alias);
let indexes_to_update = if rowid_alias_used {
// If the rowid alias is used in the SET clause, we need to update all indexes
indexes.cloned().collect()
} else {
// otherwise we need to update the indexes whose columns are set in the SET clause,
// or if the colunns used in the partial index WHERE clause are being updated
indexes
.filter_map(|idx| {
let mut needs = idx
.columns
.iter()
.any(|c| updated_cols.contains(&c.pos_in_table));
if !needs {
if let Some(w) = &idx.where_clause {
let mut where_copy = w.as_ref().clone();
let mut param = ParamState::disallow();
let mut tr =
TableReferences::new(table_references.joined_tables().to_vec(), vec![]);
bind_and_rewrite_expr(
&mut where_copy,
Some(&mut tr),
None,
connection,
&mut param,
BindingBehavior::ResultColumnsNotAllowed,
)
.ok()?;
let cols_used = collect_cols_used_in_expr(&where_copy);
// if any of the columns used in the partial index WHERE clause is being
// updated, we need to update this index
needs = cols_used.iter().any(|c| updated_cols.contains(c));
}
}
if needs {
Some(idx.clone())
} else {
None
}
})
.collect()
};
Ok(Plan::Update(UpdatePlan {
table_references,
set_clauses,
where_clause,
returning: if result_columns.is_empty() {
None
} else {
Some(result_columns)
},
order_by,
limit,
offset,
contains_constant_false_condition: false,
indexes_to_update,
ephemeral_plan: None,
cdc_update_alter_statement: None,
}))
}
fn build_scan_op(table: &Table, iter_dir: IterationDirection) -> Operation {
match table {
Table::BTree(_) => Operation::Scan(Scan::BTreeTable {
iter_dir,
index: None,
}),
Table::Virtual(_) => Operation::default_scan_for(table),
_ => unreachable!(),
}
}
/// Returns a set of column indices used in the expression.
/// *Must* be used on an Expr already processed by `bind_and_rewrite_expr`
fn collect_cols_used_in_expr(expr: &Expr) -> HashSet<usize> {
let mut acc = HashSet::new();
let _ = walk_expr(expr, &mut |expr| match expr {
Expr::Column { column, .. } => {
acc.insert(*column);
Ok(WalkControl::Continue)
}
_ => Ok(WalkControl::Continue),
});
acc
}