sql: fix bug with needed column families and nulls #41212
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When doing point lookups, we have logic to only scan column families which are needed for the requested columns. However, this logic had a bug concerning NULL values. Column families other than the one with ID 0 do not store a row if all their columns are NULL. This means that if you only scan those families, you can't distinguish between the absence of a row and all NULL values. Since we didn't account for this, some queries which should have returned an all NULL row were instead returning no row. See the referenced issue for specific examples. For now I have fixed this by always including column family 0 in the needed column families. There are some special cases where we could omit it, but we'll save those for the 20.1 release. Fixes cockroachdb#41007 Release note: None Release justification: Correctness bug fix
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41212: sql: fix bug with needed column families and nulls r=solongordon a=solongordon When doing point lookups, we have logic to only scan column families which are needed for the requested columns. However, this logic had a bug concerning NULL values. Column families other than the one with ID 0 do not store a row if all their columns are NULL. This means that if you only scan those families, you can't distinguish between the absence of a row and all NULL values. Since we didn't account for this, some queries which should have returned an all NULL row were instead returning no row. See the referenced issue for specific examples. For now I have fixed this by always including column family 0 in the needed column families. There are some special cases where we could omit it, but we'll save those for the 20.1 release. Fixes #41007 Release note: None Release justification: Correctness bug fix Co-authored-by: Solon Gordon <[email protected]>
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When doing point lookups, we have logic to only scan column families
which are needed for the requested columns. However, this logic had a
bug concerning NULL values. Column families other than the one with ID 0
do not store a row if all their columns are NULL. This means that if you
only scan those families, you can't distinguish between the absence of a
row and all NULL values. Since we didn't account for this, some queries
which should have returned an all NULL row were instead returning no
row. See the referenced issue for specific examples.
For now I have fixed this by always including column family 0 in the
needed column families. There are some special cases where we could omit
it, but we'll save those for the 20.1 release.
Fixes #41007
Release note: None
Release justification: Correctness bug fix