Row-level rpair hashes the mutation fragment and wraps this into a
private fragment_hasher class. For some reason it takes ~20 minutes
for clang to compile the row_level.o with -O3 level (release mode).
Putting the whole fragment_hasher into a dedicated file reduces the
compilation times ~9 times.
However, it seems more natural not to move the fragment_hasher around
but to specialize the appending_hash<> for mutation_fragment and make
row_level.cc code just call feed_hash().
Compilation times (release mode):
before after
row_level.o 19m34s 2m4s
mutation_fragment.o 13s 17s
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Next patch is going to change the way row-level repair code hashes
mutation_fragment objects. This patch prepares the sanity check for
the hash values not be accidentally changed by hashing some simple
fragments and comparing them against known expected values.
The hash_mutation_fragment_for_test helper is added for this patch
only and will be removed really soon.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
This test is a sanity check. It verifies that our wrappers over well known
hashes (xxhash, md5, sha256) actually calculate exactly those hashes.
It also checks that the `update()` methods of used hashers are linear with
respect to concatenation: that is, `update(a + b)` must be equivalent to
`update(a); update(b)`. This wasn't relied on before, but now we need to
confirm that hashing fragmented keys without linearizing them won't break
backward compatibility.
