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plan_satisfies_order_target(): simplify

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This commit is contained in:
Jussi Saurio
2025-05-12 11:45:24 +03:00
parent 4dde356d97
commit fe628e221a
2 changed files with 51 additions and 78 deletions
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15
core/translate/optimizer/access_method.rs
View File

@@ -23,6 +23,21 @@ pub struct AccessMethod<'a> {
pub kind: AccessMethodKind<'a>,
}
impl<'a> AccessMethod<'a> {
pub fn index(&self) -> Option<&Index> {
match &self.kind {
AccessMethodKind::Scan { index, .. } => index.as_ref().map(|i| i.as_ref()),
AccessMethodKind::Search { index, .. } => index.as_ref().map(|i| i.as_ref()),
}
}
pub fn iter_dir(&self) -> IterationDirection {
match &self.kind {
AccessMethodKind::Scan { iter_dir, .. } => *iter_dir,
AccessMethodKind::Search { iter_dir, .. } => *iter_dir,
}
}
}
#[derive(Debug, Clone)]
/// Represents the kind of access method.
pub enum AccessMethodKind<'a> {

114
core/translate/optimizer/order.rs
View File

@@ -7,10 +7,7 @@ use crate::{
util::exprs_are_equivalent,
};
use super::{
access_method::{AccessMethod, AccessMethodKind},
join::JoinN,
};
use super::{access_method::AccessMethod, join::JoinN};
#[derive(Debug, PartialEq, Clone)]
/// A convenience struct for representing a (table_no, column_no, [SortOrder]) tuple.
@@ -138,7 +135,8 @@ pub fn compute_order_target(
}
}
/// Check if the plan's row iteration order matches the [OrderTarget]'s column order
/// Check if the plan's row iteration order matches the [OrderTarget]'s column order.
/// If yes, and this plan is selected, then a sort operation can be eliminated.
pub fn plan_satisfies_order_target(
plan: &JoinN,
access_methods_arena: &RefCell<Vec<AccessMethod>>,
@@ -146,15 +144,22 @@ pub fn plan_satisfies_order_target(
order_target: &OrderTarget,
) -> bool {
let mut target_col_idx = 0;
let num_cols_in_order_target = order_target.0.len();
for (i, table_no) in plan.table_numbers.iter().enumerate() {
let target_col = &order_target.0[target_col_idx];
let table_ref = &table_references[*table_no];
// Check if this table has an access method that provides ordering
let correct_table = target_col.table_no == *table_no;
if !correct_table {
return false;
}
// Check if this table has an access method that provides the right ordering.
let access_method = &access_methods_arena.borrow()[plan.best_access_methods[i]];
match &access_method.kind {
AccessMethodKind::Scan {
index: None,
iter_dir,
} => {
let iter_dir = access_method.iter_dir();
let index = access_method.index();
match index {
None => {
// No index, so the next required column must be the rowid alias column.
let rowid_alias_col = table_ref
.table
.columns()
@@ -163,92 +168,45 @@ pub fn plan_satisfies_order_target(
let Some(rowid_alias_col) = rowid_alias_col else {
return false;
};
let target_col = &order_target.0[target_col_idx];
let order_matches = if *iter_dir == IterationDirection::Forwards {
let correct_column = target_col.column_no == rowid_alias_col;
if !correct_column {
return false;
}
// Btree table rows are always in ascending order of rowid.
let correct_order = if iter_dir == IterationDirection::Forwards {
target_col.order == SortOrder::Asc
} else {
target_col.order == SortOrder::Desc
};
if target_col.table_no != *table_no
|| target_col.column_no != rowid_alias_col
|| !order_matches
{
if !correct_order {
return false;
}
target_col_idx += 1;
if target_col_idx == order_target.0.len() {
// All order columns matched.
if target_col_idx == num_cols_in_order_target {
return true;
}
}
AccessMethodKind::Scan {
index: Some(index),
iter_dir,
} => {
// The index columns must match the order target columns for this table
Some(index) => {
// All of the index columns must match the next required columns in the order target.
for index_col in index.columns.iter() {
let target_col = &order_target.0[target_col_idx];
let order_matches = if *iter_dir == IterationDirection::Forwards {
let correct_column = target_col.column_no == index_col.pos_in_table;
if !correct_column {
return false;
}
let correct_order = if iter_dir == IterationDirection::Forwards {
target_col.order == index_col.order
} else {
target_col.order != index_col.order
};
if target_col.table_no != *table_no
|| target_col.column_no != index_col.pos_in_table
|| !order_matches
{
if !correct_order {
return false;
}
target_col_idx += 1;
if target_col_idx == order_target.0.len() {
return true;
}
}
}
AccessMethodKind::Search {
index, iter_dir, ..
} => {
if let Some(index) = index {
for index_col in index.columns.iter() {
let target_col = &order_target.0[target_col_idx];
let order_matches = if *iter_dir == IterationDirection::Forwards {
target_col.order == index_col.order
} else {
target_col.order != index_col.order
};
if target_col.table_no != *table_no
|| target_col.column_no != index_col.pos_in_table
|| !order_matches
{
return false;
}
target_col_idx += 1;
if target_col_idx == order_target.0.len() {
return true;
}
}
} else {
let rowid_alias_col = table_ref
.table
.columns()
.iter()
.position(|c| c.is_rowid_alias);
let Some(rowid_alias_col) = rowid_alias_col else {
return false;
};
let target_col = &order_target.0[target_col_idx];
let order_matches = if *iter_dir == IterationDirection::Forwards {
target_col.order == SortOrder::Asc
} else {
target_col.order == SortOrder::Desc
};
if target_col.table_no != *table_no
|| target_col.column_no != rowid_alias_col
|| !order_matches
{
return false;
}
target_col_idx += 1;
if target_col_idx == order_target.0.len() {
// All order columns matched.
if target_col_idx == num_cols_in_order_target {
return true;
}
}