"
SSTables 3.x format ('m') stores the size of previous row or RT marker
inside each row/marker. That potentially allows to traverse rows/markers
in reverse order.
The previous code calculating those sizes appeared to produce invalid
values for all rows except the first one. The problem with detecting
this bug was that neither Cassandra itself nor the sstabledump tool use
those values, they are simply rejected on reading.
From UnfilteredSerializer.deserializeRowBody() method,
https://github.com/apache/cassandra/blob/cassandra-3.11/src/java/org/apache/cassandra/db/rows/UnfilteredSerializer.java#L562
:
if (header.isForSSTable())
{
in.readUnsignedVInt(); // Skip row size
in.readUnsignedVInt(); // previous unfiltered size
}
So while the previous test files were technically correct in that they
contained valid data readable by Cassandra/sstabledump, they didn't
follow the format specification.
This patchset fixes the code to produce correct values and replaces
incorrect data files with correct ones. The newly generated data files
have been validated to be identical to files generated with Cassandra
using same data and timestamps as unit tests.
Tests: Unit {release}
"
* 'projects/sstables-30/fix-prev-row_size/v1' of https://github.com/argenet/scylla:
tests: Fix test files to use correct previous row sizes.
sstables: Fix calculation of previous row size for SSTables 3.x
sstables: Factor out code building promoted index blocks into separate helpers.
6f2d3b7f9f