vinodkc opened a new pull request, #53312:
URL: https://github.com/apache/spark/pull/53312
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### What changes were proposed in this pull request?
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This PR adds support for collecting column statistics for the TIME data type
to enable optimization for queries involving TIME columns.
### Why are the changes needed?
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Without statistics collection support for TIME columns, Spark cannot make
informed decisions for queries involving TIME predicates and join
### Does this PR introduce _any_ user-facing change?
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Yes, users can now collect statistics for TIME columns
Before this PR:
```
CREATE TABLE events (id INT, event_time TIME(6)) USING parquet;
ANALYZE TABLE events COMPUTE STATISTICS FOR COLUMNS event_time;
-- No statistics collected, optimizer cannot use TIME column info
```
After this PR:
```
CREATE TABLE events (id INT, event_time TIME(6)) USING parquet;
ANALYZE TABLE events COMPUTE STATISTICS FOR COLUMNS event_time;
-- Statistics collected: min, max, distinct count, null count
DESCRIBE EXTENDED events event_time;
-- Shows:
-- min: 08:00:00.000000
-- max: 18:00:00.000000
-- num_nulls: 5
-- distinct_count: 1000
-- avg_col_len: 8
-- max_col_len: 8
-- histogram: NULL
```
Note : `histogram: NULL` as TIME represents time-of-day, which is
fundamentally circular/periodic data, while histograms are designed for linear
data with a clear progression.
### How was this patch tested?
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Added tests in `StatisticsCollectionSuite, StatisticsCollectionTestBase,
StatisticsSuite `
Manual Testing:
```
-- Test various precisions
CREATE TABLE time_test (
t0 TIME(0), t1 TIME(1), t2 TIME(2),
t3 TIME(3), t4 TIME(4), t5 TIME(5), t6 TIME(6)
) USING parquet;
INSERT INTO time_test VALUES
(TIME '08:00:00', TIME '08:00:00.1', TIME '08:00:00.12',
TIME '08:00:00.123', TIME '08:00:00.1234',
TIME '08:00:00.12345', TIME '08:00:00.123456');
ANALYZE TABLE time_test COMPUTE STATISTICS FOR COLUMNS
t0, t1, t2, t3, t4, t5, t6;
-- Verify all columns have statistics
DESCRIBE EXTENDED time_test t0;
DESCRIBE EXTENDED time_test t6;
```
### Was this patch authored or co-authored using generative AI tooling?
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No.
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