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docs: more comment on accums internal

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discord9
2024-04-24 19:34:24 +08:00
parent 96b2871750
commit 843ef050d6
1 changed files with 7 additions and 2 deletions
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9
src/flow/src/compute/render/reduce.rs
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@@ -344,8 +344,13 @@ fn reduce_distinct_subgraph(
///
/// the data being send is just new rows that represent the new output after given input is processed
///
/// i.e: for example before new updates comes in, the output of query `SELECT sum(number) FROM table`
/// is 10, and after new updates comes in, the output is 15, then the new row being send is (15, now, 1)
/// i.e: for example before new updates comes in, the output of query `SELECT sum(number), count(number) FROM table`
/// is (10,2(), and after new updates comes in, the output is (15,3), then the new row being send is ((15, 3), now, 1)
///
/// while it will also update key -> accums's value, for example if it is empty before, it will become something like
/// |offset| accum for sum | accum for count |
/// where offset is a single value holding the end offset of each accumulator
/// and the rest is the actual accumulator values which could be multiple values
fn reduce_accum_subgraph(
arrange: &ArrangeHandler,
distinct_input: &Option<Vec<ArrangeHandler>>,