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Rename ljbk to left_join and left_join_bookkeeping to left_join_maybe

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This commit is contained in:
jussisaurio
2024-07-27 16:38:40 +03:00
parent 700d9ee976
commit fee33cfcf0
1 changed files with 26 additions and 23 deletions
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49
core/translate/select.rs
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@@ -110,7 +110,7 @@ pub struct LoopInfo {
// The table or table alias that we are looping over
pub identifier: String,
// Metadata about a left join, if any
pub left_join_bookkeeping: Option<LeftJoinBookkeeping>,
pub left_join_maybe: Option<LeftJoinBookkeeping>,
// The label for the instruction that reads the next row for this table
pub next_row_label: BranchOffset,
// The label for the instruction that rewinds the cursor for this table
@@ -526,8 +526,8 @@ fn translate_tables_begin(
for loop_info in &select.loops {
// if there is a left join and there is a condition on the join that is always false,
// every row in the outer table will be emitted with nulls for the right table
let early_terminate_label = if let Some(ljbk) = &loop_info.left_join_bookkeeping {
ljbk.check_match_flag_label
let early_terminate_label = if let Some(left_join) = &loop_info.left_join_maybe {
left_join.check_match_flag_label
} else {
// if there is an inner join or a where (same thing) and the condition is always false,
// no rows will be emitted
@@ -559,8 +559,8 @@ fn translate_tables_end(program: &mut ProgramBuilder, select: &Select) {
table_loop.rewind_label,
);
if let Some(ljbk) = &table_loop.left_join_bookkeeping {
left_join_match_flag_check(program, ljbk, cursor_id);
if let Some(left_join) = &table_loop.left_join_maybe {
left_join_match_flag_check(program, left_join, cursor_id);
}
}
}
@@ -579,7 +579,7 @@ fn translate_table_open_cursor(program: &mut ProgramBuilder, table: &SrcTable) -
program.emit_insn(Insn::OpenReadAwait);
LoopInfo {
identifier: table.identifier.clone(),
left_join_bookkeeping: if table.is_outer_join() {
left_join_maybe: if table.is_outer_join() {
Some(LeftJoinBookkeeping {
match_flag_register: program.alloc_register(),
on_match_jump_to_label: program.allocate_label(),
@@ -600,21 +600,24 @@ fn translate_table_open_cursor(program: &mut ProgramBuilder, table: &SrcTable) -
* initialize left join match flag to false
* if condition checks pass, it will eventually be set to true
*/
fn left_join_match_flag_initialize(program: &mut ProgramBuilder, ljbk: &LeftJoinBookkeeping) {
fn left_join_match_flag_initialize(program: &mut ProgramBuilder, left_join: &LeftJoinBookkeeping) {
program.emit_insn(Insn::Integer {
value: 0,
dest: ljbk.match_flag_register,
dest: left_join.match_flag_register,
});
}
/**
* after the relevant conditional jumps have been emitted, set the left join match flag to true
*/
fn left_join_match_flag_set_true(program: &mut ProgramBuilder, ljbk: &LeftJoinBookkeeping) {
program.defer_label_resolution(ljbk.set_match_flag_true_label, program.offset() as usize);
fn left_join_match_flag_set_true(program: &mut ProgramBuilder, left_join: &LeftJoinBookkeeping) {
program.defer_label_resolution(
left_join.set_match_flag_true_label,
program.offset() as usize,
);
program.emit_insn(Insn::Integer {
value: 1,
dest: ljbk.match_flag_register,
dest: left_join.match_flag_register,
});
}
@@ -627,31 +630,31 @@ fn left_join_match_flag_set_true(program: &mut ProgramBuilder, ljbk: &LeftJoinBo
*/
fn left_join_match_flag_check(
program: &mut ProgramBuilder,
ljbk: &LeftJoinBookkeeping,
left_join: &LeftJoinBookkeeping,
cursor_id: usize,
) {
// If the left join match flag has been set to 1, we jump to the next row on the outer table (result row has been emitted already)
program.resolve_label(ljbk.check_match_flag_label, program.offset());
program.resolve_label(left_join.check_match_flag_label, program.offset());
program.emit_insn_with_label_dependency(
Insn::IfPos {
reg: ljbk.match_flag_register,
target_pc: ljbk.on_match_jump_to_label,
reg: left_join.match_flag_register,
target_pc: left_join.on_match_jump_to_label,
decrement_by: 0,
},
ljbk.on_match_jump_to_label,
left_join.on_match_jump_to_label,
);
// If not, we set the right table cursor's "pseudo null bit" on, which means any Insn::Column will return NULL
program.emit_insn(Insn::NullRow { cursor_id });
// Jump to setting the left join match flag to 1 again, but this time the right table cursor will set everything to null
program.emit_insn_with_label_dependency(
Insn::Goto {
target_pc: ljbk.set_match_flag_true_label,
target_pc: left_join.set_match_flag_true_label,
},
ljbk.set_match_flag_true_label,
left_join.set_match_flag_true_label,
);
// This points to the NextAsync instruction of the next table in the loop
// (i.e. the outer table, since we're iterating in reverse order)
program.resolve_label(ljbk.on_match_jump_to_label, program.offset());
program.resolve_label(left_join.on_match_jump_to_label, program.offset());
}
fn translate_table_open_loop(
@@ -661,8 +664,8 @@ fn translate_table_open_loop(
w: &ProcessedWhereClause,
early_terminate_label: BranchOffset,
) -> Result<()> {
if let Some(ljbk) = loop_info.left_join_bookkeeping.as_ref() {
left_join_match_flag_initialize(program, ljbk);
if let Some(left_join) = loop_info.left_join_maybe.as_ref() {
left_join_match_flag_initialize(program, left_join);
}
program.emit_insn(Insn::RewindAsync {
@@ -679,8 +682,8 @@ fn translate_table_open_loop(
translate_processed_where(program, select, loop_info, w, early_terminate_label, None)?;
if let Some(ljbk) = loop_info.left_join_bookkeeping.as_ref() {
left_join_match_flag_set_true(program, ljbk);
if let Some(left_join) = loop_info.left_join_maybe.as_ref() {
left_join_match_flag_set_true(program, left_join);
}
Ok(())