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feat: Add the in-commit timestamp field to CommitInfo #581

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Merged
merged 13 commits into from
Jan 15, 2025
Merged

feat: Add the in-commit timestamp field to CommitInfo #581

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a513a09
Add ict and tests
OussamaSaoudi-db Dec 9, 2024
bc3ff0c
Update docs for ICT
OussamaSaoudi-db Dec 9, 2024
db5e301
Assert selection vector
OussamaSaoudi-db Dec 9, 2024
c57c645
wip ict impl
OussamaSaoudi-db Dec 10, 2024
64efb75
add tmp ict fixup for writes
OussamaSaoudi-db Dec 11, 2024
e2f44b9
remove non_ict schema
OussamaSaoudi-db Dec 11, 2024
acac33c
fix commit
OussamaSaoudi-db Dec 30, 2024
f52b5fc
Remove cdf changes for ict
OussamaSaoudi-db Dec 30, 2024
ae2b7d1
remove unused imports
OussamaSaoudi-db Dec 30, 2024
f8909ba
Add clarifying comment for inCommitTimestamp
OussamaSaoudi-db Dec 30, 2024
fb1ff2f
Add documentation for ICT
OussamaSaoudi-db Jan 10, 2025
7258611
Merge branch 'main' into cdf_ict
OussamaSaoudi-db Jan 14, 2025
d37a191
Merge branch 'main' into cdf_ict
OussamaSaoudi Jan 15, 2025
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6 changes: 5 additions & 1 deletion kernel/src/actions/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -331,8 +331,11 @@ where
struct CommitInfo {
/// The time this logical file was created, as milliseconds since the epoch.
/// Read: optional, write: required (that is, kernel always writes).
/// If in-commit timestamps are enabled, this is always required.
pub(crate) timestamp: Option<i64>,
/// The time this logical file was created, as milliseconds since the epoch. Unlike
/// `timestamp`, this field is guaranteed to be monotonically increase with each commit.
/// If in-commit timestamps are enabled, this is always required.
pub(crate) in_commit_timestamp: Option<i64>,
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maybe also note that (when enabled) it requires that commitInfo be the first action in the commit?

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While that's technically what the protocol says, delta-spark doesn't check that this is true. It simply extracts the CommitInfo if present.

I think the error handling would be more code and let us capture fewer tables than delta spark, and commitInfo being the first action doesn't seem to impact us much in this scenario.

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@scovich scovich Jan 9, 2025 •
edited
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Delta-spark doesn't check, but it also does stop looking after the first line of json. So if the commit info is not first it will appear to not exist at all. Sometimes that causes an error downstream, and sometimes it would cause a silent wrong behavior.

I would prefer to check strictly unless/until we see a need to do otherwise.

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@scovich Do you recommend that we error, or just ignore the ICT

/// An arbitrary string that identifies the operation associated with this commit. This is
/// specified by the engine. Read: optional, write: required (that is, kernel alwarys writes).
pub(crate) operation: Option<String>,
Expand Down Expand Up @@ -694,6 +697,7 @@ mod tests {
"commitInfo",
StructType::new(vec![
StructField::new("timestamp", DataType::LONG, true),
StructField::new("inCommitTimestamp", DataType::LONG, true),
StructField::new("operation", DataType::STRING, true),
StructField::new(
"operationParameters",
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6 changes: 6 additions & 0 deletions kernel/src/transaction.rs
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Expand Up @@ -315,6 +315,12 @@ fn generate_commit_info(
.get_mut("operationParameters")
.ok_or_else(|| Error::missing_column("operationParameters"))?
.data_type = hack_data_type;

// Since writing in-commit timestamps is not supported, we remove the field so it is not
// written to the log
commit_info_data_type
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@zachschuermann just flagging this comment and approach to writing ICT.

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seems fine :) can we add an issue link/todo so we are tracking this?

.fields
.shift_remove("inCommitTimestamp");
commit_info_field.data_type = DataType::Struct(commit_info_data_type);

let commit_info_evaluator = engine.get_expression_handler().get_evaluator(
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