Hi hackers, restore_tuple() in repack.c uses SET_VARSIZE() to reconstruct the varlena header when reading back external attributes from the spill file. In this process, looks like the flag SET_VARSIZE_COMPRESSED is silently lost. Because of this, when REPACK CONCURRENTLY run any concurrently updated column whose value was TOAST-compressed ends up with raw compressed bytes behind an "uncompressed" header returning garbled data on subsequent reads. It appears that existing tests are using random chars which are uncompressable.
Please find the attached 0001-Fix-restore_tuple-losing-varlena-compression-flag.patch to fix this. Additionally I updated the existing repack_toast test to include the scenario I was talking about. Thanks, Satya
0001-Fix-restore_tuple-losing-varlena-compression-flag.patch
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0002-Add-compressed-TOAST-test-to-repack_toast.patch
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