feat: export persist_period_sec option and background_threads

[developerfred]

exported functions:

• set_low_priority_background_threads
• set_bottom_priority_background_threads
• env_default feat: export Env::default() facebook/rocksdb#7207
• set_stats_persist_period_sec

close #447

Export PR on RocksDB
facebook/rocksdb#7168

[aleksuss]

Thanks for the contributing. Overall looks good. But could you add some tests ?

[developerfred]

@aleksuss Yes! I'll add now. thanks for the quick feedback

[ailisp]

@developerfred expose set_stats_persist_period_sec looks good, but disable background threads isn't done. Env::Default()->SetBackgroundThreads(0, Env::Priority::BOTTOM); // **need export** is a different function than max_background_jobs. Which you can tested by:

1. launch program with lldb, place a break point before:

             assert_eq!(k.as_ref(), format!("{:0>4}", expected).as_bytes());

2. run thread list

Without Env::Default()->SetBackgroundThreads you'll see 3+ threads. (set_stats_persist_period_sec will turn off one thread, but there's still two other background threads). Expected only 1 thread with Env::Default()->SetBackgroundThreads, for example, run lldb with this: https://github.com/nearprotocol/rocksdb/blob/no-thread-test/examples/compact_files_example.cc

[developerfred]

@ailisp I will open a new pull request to export the Env::Default()->SetBackgroundThreads(0, Env::Priority::BOTTOM);

[developerfred]

@ailisp I exported how rocksdb_env_set_background_threads_disable

[ailisp]

@ailisp I exported how rocksdb_env_set_background_threads_disable

It might be good idea to follow their naming (lines before your change)

void rocksdb_env_set_high_priority_background_threads(rocksdb_env_t* env, int n) {
  env->rep->SetBackgroundThreads(n, Env::HIGH);
}

Also please also export Env::Default()->SetBackgroundThreads(0, Env::Priority::LOW)? Thanks!

[developerfred]

@ailisp done 👍🏾 - rocksdb_env_set_bottom_priority_background_threads and rocksdb_env_set_low_priority_background_threads

facebook/rocksdb@19180d5

[developerfred]

@ailisp Bump done

2c3d7d7

[ailisp]

@developerfred My bad in test, your PRs fully works, it just takes some time to wait rocksdb destroy other threads (wait some seconds and lldb attach there's only one thread). I'm very sorry of that. So no need to export Env::Default (ust-rocksdb/rust-rocksdb#448)

[developerfred]

@ailisp ok! No problem!

[ailisp]

@developerfred We've successfully use your fork on our repo, Thank you! looking forward to next rust-rocksdb release, to upgrade your changes in c++ rocksdb and land this PR

[ailisp]

@stanislav-tkach Facebook has released rocksdb containing @developerfred 's change and it's been bumped in rust-rocksdb, let's merge this PR? (@developerfred Would you mind resolve conflict? I cannot push to your branch, if you don't have time I can fork from your fork, resolve conflict and make a new PR, then close this one)

[developerfred]

@stanislav-tkach Facebook has released rocksdb containing @developerfred 's change and it's been bumped in rust-rocksdb, let's merge this PR? (@developerfred Would you mind resolve conflict? I cannot push to your branch, if you don't have time I can fork from your fork, resolve conflict and make a new PR, then close this one)

I solve this now, thanks for information and ping.

[aleksuss]

@developerfred apply please suggestions by fmt and clippy.

[developerfred]

ok @aleksuss

[ailisp]

Thank you @developerfred and @aleksuss !