mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-18 05:32:52 +00:00
53 lines
2.1 KiB
C++
53 lines
2.1 KiB
C++
#include <city.h>
|
|
#include <iostream>
|
|
#include <IO/ReadBufferFromFileDescriptor.h>
|
|
#include <IO/ReadHelpers.h>
|
|
#include <Common/hex.h>
|
|
|
|
|
|
/** A tool to easily prove if "Checksum doesn't match: corrupted data"
|
|
* errors are caused by random bit flips due to hardware issues.
|
|
* It frequently happens due to bad memory on network switches
|
|
* (at least about a few times a year in a fleet of ~1200 ClickHouse servers).
|
|
*
|
|
* These hardware errors don't cause any data corruption issues in ClickHouse,
|
|
* because ClickHouse always validate it's own 128 bit checksums
|
|
* and report errors if checksum doesn't match.
|
|
*
|
|
* Client can simply retry the query.
|
|
* But ops engineers want to validate if the issue is real hardware error or not.
|
|
* If checksum difference is caused by single bit flip,
|
|
* we can be sure that this is hardware error, because random bit flips
|
|
* have low probability to happen due to software bugs.
|
|
*
|
|
* Usage:
|
|
|
|
echo -ne "\x82\x6b\x00\x00\x00\x62\x00\x00\x00\xf2\x3b\x01\x00\x02\xff\xff\xff\xff\x00\x01\x01\x2c\x75\x6e\x69\x71\x49\x66\x28\x44\x65\x76\x69\x63\x65\x49\x44\x48\x61\x73\x68\x2c\x20\x65\x71\x75\x61\x6c\x73\x28\x53\x65\x73\x73\x69\x6f\x6e\x54\x79\x70\x65\x2c\x20\x30\x29\x29\x28\x41\x67\x67\x72\x65\x67\x61\x74\x65\x46\x75\x6e\x63\x74\x69\x6f\x6e\x28\x3f\x00\xf0\x03\x2c\x20\x55\x49\x6e\x74\x36\x34\x2c\x20\x55\x49\x6e\x74\x38\x29\x00\x00" | ./checksum-for-compressed-block-find-bit-flips | grep 8b40502d2ffe5b712b52e03c505ca49f
|
|
8b40502d2ffe5b712b52e03c505ca49f 32, 6
|
|
*/
|
|
|
|
|
|
std::string flipBit(std::string s, size_t pos)
|
|
{
|
|
s[pos / 8] ^= 1 << pos % 8;
|
|
return s;
|
|
}
|
|
|
|
|
|
int main(int, char **)
|
|
{
|
|
using namespace DB;
|
|
ReadBufferFromFileDescriptor in(STDIN_FILENO);
|
|
std::string str;
|
|
readStringUntilEOF(str, in);
|
|
|
|
for (size_t pos = 0; pos < str.size() * 8; ++pos)
|
|
{
|
|
auto flipped = flipBit(str, pos);
|
|
auto checksum = CityHash_v1_0_2::CityHash128(flipped.data(), flipped.size());
|
|
std::cout << getHexUIntLowercase(checksum.first) << getHexUIntLowercase(checksum.second) << "\t" << pos / 8 << ", " << pos % 8 << "\n";
|
|
}
|
|
|
|
return 0;
|
|
}
|