Better error: Print checksums if they mismatch

dbms/src/IO/CompressedReadBufferBase.cpp

@@ -9,6 +9,7 @@
 #include <Common/PODArray.h>
 #include <Common/ProfileEvents.h>
 #include <Common/Exception.h>
+#include <Common/hex.h>
 #include <common/unaligned.h>
 #include <IO/ReadBuffer.h>
 #include <IO/BufferWithOwnMemory.h>
@@ -63,7 +64,7 @@ size_t CompressedReadBufferBase::readCompressedData(size_t & size_decompressed,
         throw Exception("Unknown compression method: " + toString(method), ErrorCodes::UNKNOWN_COMPRESSION_METHOD);
 
     if (size_compressed > DBMS_MAX_COMPRESSED_SIZE)
-        throw Exception("Too large size_compressed. Most likely corrupted data.", ErrorCodes::TOO_LARGE_SIZE_COMPRESSED);
+        throw Exception("Too large size_compressed=" + toString(size_compressed) + ". Most likely corrupted data.", ErrorCodes::TOO_LARGE_SIZE_COMPRESSED);
 
     ProfileEvents::increment(ProfileEvents::ReadCompressedBytes, size_compressed + sizeof(checksum));
 
@@ -82,8 +83,15 @@ size_t CompressedReadBufferBase::readCompressedData(size_t & size_decompressed,
         compressed_in->readStrict(compressed_buffer + COMPRESSED_BLOCK_HEADER_SIZE, size_compressed - COMPRESSED_BLOCK_HEADER_SIZE);
     }
 
-    if (!disable_checksum && checksum != CityHash_v1_0_2::CityHash128(compressed_buffer, size_compressed))
-        throw Exception("Checksum doesn't match: corrupted data.", ErrorCodes::CHECKSUM_DOESNT_MATCH);
+    if (!disable_checksum) {
+        auto checksum_calculated = CityHash_v1_0_2::CityHash128(compressed_buffer, size_compressed);
+        if (checksum != checksum_calculated)
+            throw Exception("Checksum doesn't match: corrupted data."
+                " received=" + getHexUIntLowercase(checksum.first) + getHexUIntLowercase(checksum.second)
+                + ", calculated=" + getHexUIntLowercase(checksum_calculated.first) + getHexUIntLowercase(checksum_calculated.second)
+                + ", size=" + toString(size_compressed),
+                ErrorCodes::CHECKSUM_DOESNT_MATCH);
+    }
 
     return size_compressed + sizeof(checksum);
 }