Handle Date Underflow

[kamuli4]

Attempting to resolve #595

Takes in a date (MM-DD-YYYY) and formats it to ISO 8601 (YYYY-MM-DD), then compares if it is below the lowest PostgreSQL date (4713 BC or -4712-01-01 in ISO 8601). Truncates the entered date to the lowest Postgres if it is further in the past than Postgres allows. Similar logic is applied if the date is further in the future than Postgres allows. Returns the user-entered date in ISO 8601 format if it is a valid date

[JelteF]

I'm a bit confused. How is this supposed to work? These functions are not being called afaict.

[kamuli4]

I should've asked in the original issue, but I did a quick look and didn't see any files that looked like they control date formatting and verification, could you point me to the file(s) that handle that feature? Would it be the original file referenced in #595 or src/pgduckdb_types by any chance?

[JelteF]

I updated the original issue to include this query that triggers these underflowing dates:

SELECT * FROM duckdb.query($$
    select
        '5877642-06-25 (BC)'::date as date,
        '290309-12-22 (BC) 00:00:00'::timestamp as timestamp,
        '290309-12-22 (BC) 00:00:00'::timestamp_s as timestamp_s,
        '290309-12-22 (BC) 00:00:00'::timestamp_ms as timestamp_ms,
        '290309-12-22 (BC) 00:17:30+00:17'::timestamptz as timestamptz,
$$);
     date      │          timestamp           │         timestamp_s          │         timestamp_ms         │           timestamptz
───────────────┼──────────────────────────────┼──────────────────────────────┼──────────────────────────────┼─────────────────────────────────
 5881580-07-14 │ 294247-01-10 08:01:49.551616 │ 294247-01-10 08:01:49.551616 │ 294247-01-10 08:01:49.551616 │ 294247-01-10 09:02:19.551616+01
(1 row)

And yes this conversion between PG and DuckDB date format is being done in the pgduckdb_types.cpp file.

[JelteF]

The conversion is done in these functions to be specific:

pg_duckdb/src/pgduckdb_types.cpp

Lines 215 to 255 in 82d3a0f

	inline Datum
	ConvertDateDatum(const duckdb::Value &value) {
	duckdb::date_t date = value.GetValue<duckdb::date_t>();
	return date.days - pgduckdb::PGDUCKDB_DUCK_DATE_OFFSET;
	}
	static Datum
	ConvertIntervalDatum(const duckdb::Value &value) {
	duckdb::interval_t duckdb_interval = value.GetValue<duckdb::interval_t>();
	Interval *pg_interval = static_cast<Interval *>(palloc(sizeof(Interval)));
	pg_interval->month = duckdb_interval.months;
	pg_interval->day = duckdb_interval.days;
	pg_interval->time = duckdb_interval.micros;
	return IntervalPGetDatum(pg_interval);
	}
	inline Datum
	ConvertTimestampDatum(const duckdb::Value &value) {
	// Extract raw int64_t value of timestamp
	int64_t rawValue = value.GetValue<int64_t>();
	// Handle specific Timestamp unit(sec, ms, ns) types
	switch (value.type().id()) {
	case duckdb::LogicalType::TIMESTAMP_MS:
	// 1 ms = 10^3 micro-sec
	rawValue *= 1000;
	break;
	case duckdb::LogicalType::TIMESTAMP_NS:
	// 1 ns = 10^-3 micro-sec
	rawValue /= 1000;
	break;
	case duckdb::LogicalType::TIMESTAMP_S:
	// 1 s = 10^6 micro-sec
	rawValue *= 1000000;
	break;
	default:
	// Since we don't want to handle anything here
	break;
	}
	return rawValue - pgduckdb::PGDUCKDB_DUCK_TIMESTAMP_OFFSET;
	}