db_stress sometimes generates keys close to SST file boundaries (#6037)

Summary:
Recently, a bug was found related to a seek key that is close to SST file boundary. However, it only occurs in a very small chance in db_stress, because the chance that a random key hits SST file boundaries is small. To boost the chance, with 1/16 chance, we pick keys that are close to SST file boundaries.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6037

Test Plan: Did some manual printing out, and hack to cover the key generation logic to be correct.

Differential Revision: D18598476

fbshipit-source-id: 13b76687d106c5be4e3e02a0c77fa5578105a071
main
sdong 5 years ago committed by Facebook Github Bot
parent 20b48c6478
commit 4e0dcd36df
  1. 77
      tools/db_stress_tool.cc

@ -2416,6 +2416,65 @@ class StressTest {
return column_families_[column_family_id];
}
#ifndef ROCKSDB_LITE
// Generated a list of keys that close to boundaries of SST keys.
// If there isn't any SST file in the DB, return empty list.
std::vector<std::string> GetWhiteBoxKeys(ThreadState* thread, DB* db,
ColumnFamilyHandle* cfh,
size_t num_keys) {
ColumnFamilyMetaData cfmd;
db->GetColumnFamilyMetaData(cfh, &cfmd);
std::vector<std::string> boundaries;
for (const LevelMetaData& lmd : cfmd.levels) {
for (const SstFileMetaData& sfmd : lmd.files) {
boundaries.push_back(sfmd.smallestkey);
boundaries.push_back(sfmd.largestkey);
}
}
if (boundaries.empty()) {
return {};
}
std::vector<std::string> ret;
for (size_t j = 0; j < num_keys; j++) {
std::string k =
boundaries[thread->rand.Uniform(static_cast<int>(boundaries.size()))];
if (thread->rand.OneIn(3)) {
// Reduce one byte from the string
for (int i = static_cast<int>(k.length()) - 1; i >= 0; i--) {
uint8_t cur = k[i];
if (cur > 0) {
k[i] = static_cast<char>(cur - 1);
break;
} else if (i > 0) {
k[i] = 0xFF;
}
}
} else if (thread->rand.OneIn(2)) {
// Add one byte to the string
for (int i = static_cast<int>(k.length()) - 1; i >= 0; i--) {
uint8_t cur = k[i];
if (cur < 255) {
k[i] = static_cast<char>(cur + 1);
break;
} else if (i > 0) {
k[i] = 0x00;
}
}
}
ret.push_back(k);
}
return ret;
}
#else // !ROCKSDB_LITE
std::vector<std::string> GetWhiteBoxKeys(ThreadState*, DB*,
ColumnFamilyHandle*,
size_t) {
// Not supported in LITE mode.
return {};
}
#endif // !ROCKSDB_LITE
// Given a key K, this creates an iterator which scans to K and then
// does a random sequence of Next/Prev operations.
virtual Status TestIterate(ThreadState* thread, const ReadOptions& read_opts,
@ -2457,9 +2516,21 @@ class StressTest {
auto cfh = column_families_[rand_column_families[0]];
std::unique_ptr<Iterator> iter(db_->NewIterator(readoptionscopy, cfh));
for (int64_t rkey : rand_keys) {
std::string key_str = Key(rkey);
Slice key = key_str;
std::vector<std::string> key_str;
if (thread->rand.OneIn(16)) {
// Generate keys close to lower or upper bound of SST files.
key_str = GetWhiteBoxKeys(thread, db_, cfh, rand_keys.size());
}
if (key_str.empty()) {
// If key string is not geneerated using white block keys,
// Use randomized key passe in.
for (int64_t rkey : rand_keys) {
key_str.push_back(Key(rkey));
}
}
for (const std::string& skey : key_str) {
Slice key = skey;
if (readoptionscopy.iterate_upper_bound != nullptr &&
thread->rand.OneIn(2)) {

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