Page History

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• 0 for all integer types;
• 0.0 for floating point types;
• 00000000-0000-0000-0000-000000000000 for UUID;
• 00:00:00.000000 for time;
• Jan 1, 1970 00:00:00.000000 for timestamp;
  
• Jan 1, 1 BC for date (as 1 BC immediately precedes 1 AD in the Gregorian calendar).

Integer Field Compression

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Thus for integer values it is possible to keep only their significant bytes, omitting their high insignificant bytes. That is even if the original data type of a field is INTEGER and should occupy 4 bytes but the actual value is below 128 and above -129 then we can store it just as a single byte and reflect this in the offset table.

For signed integers the most significant bit is the sign bit. Thus a compressed signed integer must be sign-extended on decompression.

In SQL standard there are no unsigned integers. So support of unsigned integers may be omitted. But if for reason such support becomes needed then a compressed unsigned integer must be zero-extended.

Corollary

If the number of fields is N and t is an array that stores a binary tuple we can find the answers for the following:

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