Add a new dummy compression called NULL #7798
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Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #7798 +/- ##
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+ Coverage 80.06% 81.90% +1.83%
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Files 190 248 +58
Lines 37181 45531 +8350
Branches 9450 11393 +1943
==========================================
+ Hits 29770 37293 +7523
- Misses 2997 3749 +752
- Partials 4414 4489 +75 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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This fixes bug timescale#7714 where adding a column with a default value (jargon: missing value) and a compressed batch with all nulls created an ambiguity. In the all null cases the compressed block was stored as a NULL value. With this change, I introduce a new special compression type, the 'NULL' compression which is a single byte place holder for an 'all-null' compressed block. This allows us to distinguish between the missing value vs the all-null values. Please note that the wrong results impacted existing tests so I updated the expected results, as well as I added reference queries before compression to prove the updated values were wrong before. A new debug only GUC was added for testing a future upgrade script, which will arrive as a separate PR. Fixes timescale#7714
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This fixes bug #7714 where adding a column with a default value (jargon: missing value) and a compressed batch with all nulls created an ambiguity. In the all null cases the compressed block was stored as a NULL value.
With this change, I introduce a new special compression type, the 'NULL' compression which is a single byte place holder for an 'all-null' compressed block. This allows us to distinguish between the missing value vs the all-null values.
Please note that the wrong results impacted existing tests so I updated the expected results, as well as I added reference queries before compression to prove the updated values were wrong before.
A new debug only GUC was added for testing a future upgrade script, which will arrive as a separate PR.
Fixes #7714