Reject FOR TIMESTAMP AS OF ... with future temporal value #12720
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findepi
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martint,
losipiuk,
alexjo2144,
hashhar and
jacob-stein
|
Currently, based on #12719 |
findepi
commented
Jun 7, 2022
| @@ -4578,6 +4582,14 @@ private void validateVersionPointer(QualifiedObjectName tableName, QueryPeriod q | |||
| if (pointer == null) { | |||
| throw semanticException(INVALID_ARGUMENTS, queryPeriod, "Pointer value cannot be NULL"); | |||
| } | |||
| long pointerTimestampMillis = unpackMillisUtc((long) coerce(type, pointer, createTimestampWithTimeZoneType(3))); | |||
| if (pointerTimestampMillis >= System.currentTimeMillis()) { | |||
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Compare with session start time.
This will make AS OF now() queries fail deterministically. (Otherwise they will work sometimes, but not always)
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Addressed.
However, i decided to do the math with maximum precision. The AS OF now() has millisecond precision and thus may be rounded to a milli that's sub-milli before the session start, thus may or may not be rejected.
The AS OF now(9) (or higher precision) will deterministically be rejected, since session start time is measured with nano precision (Instant).
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rebasing after #12719 merged. |
`StatementAnalyzer` sporadically needs to coerce a value to a desired type. Extract the existing code into a utility method.
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The time travel `FOR ... AS OF ...` syntax is meant to return consistent state of a table. The future state isn't known, so it cannot be consistently queried. Reject such queries on the engine side so that connectors do not have to deal with this complexity.
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losipiuk
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Jun 9, 2022
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The time travel
FOR ... AS OF ...syntax is meant to return consistentstate of a table. The future state isn't known, so it cannot be
consistently queried. Reject such queries on the engine side so that
connectors do not have to deal with this complexity.