Debugging synchronisation

Dependencies

• [2] AOX2XQIS Actually, with the correct functions, Unsized pages are always slower than Sized pages (especially for writing)
• [3] UAQX27N4 Tests
• [4] EAAYH6BQ Debugging put
• [5] 6UVFCERM Formatting, debugging, etc.
• [6] YWFYZNLZ Cleanup + inter-process concurrency
• [7] X3QVVQIS More debugging (del seems to work now)
• [8] FMN7X4J2 Micro-improvements, now noticeably faster than std::collections::BTreeMap
• [9] YXKP4AIW New file locks, with multiple sets of free pages
• [10] 6DMPXOAT More debugging
• [11] OP6SVMOD Resetting history
• [12] WS4ZQM4R Debugging, tests, etc.
• [13] OTWDDJE7 Trait/type cleanup
• [14] AFKBHYVE Comparing the two implementations of leaves (sized/unsized). Sized are faster for writes, slower for reads.
• [15] H3FVSQIQ Unsized pages

Change contents

• edit in sanakirja-core/src/lib.rs at line 139
  [3.495]

  [3.495]
  + }

  + pub fn null() -> Self {

  + CowPage {

  + data: core::ptr::null_mut(),

  + offset: 0,

  + }
• edit in sanakirja-core/src/btree/page_unsized/put.rs at line 160
  [3.31744]→[2.1148:1393](∅→∅)
  − }

  − {

  − let hdr = header(left.0.as_page());

  − assert_eq!(hdr.n() as u64 * 16, hdr.left_page() & 0xfff);

  − }

  − {

  − let hdr = header(right.0.as_page());

  − assert_eq!(hdr.n() as u64 * 16, hdr.left_page() & 0xfff);
• edit in sanakirja-core/src/btree/page_unsized/put.rs at line 161
  [3.31750]→[2.1394:1395](∅→∅),[2.1395]→[3.31750:31783](∅→∅),[3.31750]→[3.31750:31783](∅→∅)
  −

  − assert!(!split.0.is_null());
• edit in sanakirja-core/src/btree/page_unsized/alloc.rs at line 81
  [3.3525]→[2.1691:1795](∅→∅)
  − assert_eq!(hdr.n() as u64 * 16, hdr.left_page() & 0xfff); // Just for the test with (u64, u64).
• edit in sanakirja-core/src/btree/mod.rs at line 286
  [3.52188]

  [3.15084]
  + impl<K: Representable + ?Sized, V: Representable + ?Sized, P: BTreePage<K, V>> Db_<K, V, P> {

  + pub fn from_page(db: CowPage) -> Self {

  + Db_ {

  + db,

  + k: core::marker::PhantomData,

  + v: core::marker::PhantomData,

  + p: core::marker::PhantomData,

  + }

  + }

  + }

  +
• edit in sanakirja/src/tests.rs at line 142
  [3.9943]

  [3.9943]
  +

  + type B = btree::page::Page<u64, ()>;
• edit in sanakirja/src/tests.rs at line 147
  [3.5701]→[3.5701:5742](∅→∅)
  − type B = btree::page::Page<u64, ()>;
• edit in sanakirja/src/tests.rs at line 226
  [3.7458]

  [3.7458]
  + check_free(&mut txn, &refs);

  + debug!("{:?}", refs);

  + }

  +

  + fn check_free(txn: &mut MutTxn<&Env, ()>, refs: &BTreeMap<u64, usize>) {
• replacement in sanakirja/src/tests.rs at line 240
  [3.7726]→[3.7726:7790](∅→∅)
  − while let Some((k, _)) = curs.next(&mut txn).unwrap() {
  [3.7726]

  [3.7790]
  + while let Some((k, _)) = curs.next(txn).unwrap() {
• edit in sanakirja/src/tests.rs at line 242
  [3.7827]

  [3.7827]
  + assert!(refs.get(k).is_none())
• replacement in sanakirja/src/tests.rs at line 245
  [3.7843]→[3.7843:7869](∅→∅)
  − debug!("{:?}", refs);
  [3.7843]

  [3.7869]
  + for (r, _) in refs.iter() {

  + assert!(*r < txn.length)

  + }
• edit in sanakirja/src/tests.rs at line 285
  [3.1751]→[3.1751:1793](∅→∅)
  − env_logger::try_init().unwrap_or(());
• replacement in sanakirja/src/tests.rs at line 287
  [3.1912]→[3.1912:2076](∅→∅),[3.2076]→[3.2467:2539](∅→∅),[3.2539]→[3.2152:2283](∅→∅),[3.2152]→[3.2152:2283](∅→∅),[3.2283]→[3.2540:2589](∅→∅),[3.2589]→[3.2336:2381](∅→∅),[3.2336]→[3.2336:2381](∅→∅),[3.2381]→[3.27376:27436](∅→∅),[3.27436]→[3.2444:2536](∅→∅),[3.2444]→[3.2444:2536](∅→∅),[3.2536]→[3.2590:2639](∅→∅),[3.2639]→[3.2589:2688](∅→∅),[3.2589]→[3.2589:2688](∅→∅)
  − let env = Env::new("/tmp/sanakirja0", 4096 * 20, 2).unwrap();

  − let mut txn = Env::mut_txn_begin(&env).unwrap();

  − debug!("txn.root = {:?}", txn.env.root);

  − let db = create_db::<MutTxn<&Env, ()>, u64, ()>(&mut txn).unwrap();

  − debug!("db = {:?}", db.db.offset);

  − txn.set_root(0, db.db.offset);

  − txn.commit().unwrap();

  − debug!("1. commit done");

  − let txn = Env::mut_txn_begin(&env).unwrap();

  − debug!("txn.root = {:?}", txn.env.root);

  − let db: Db<u64, ()> = txn.root_db(0).unwrap().unwrap();

  − debug!("txn.root = {:?}", db);

  − txn.commit().unwrap();

  − debug!("2. commit done");

  − let txn = Env::mut_txn_begin(&env).unwrap();

  − debug!("txn.root = {:?}", txn.env.root);

  − txn.commit().unwrap();

  − debug!("commit done");
  [3.1912]

  [3.2688]
  +

  + env_logger::try_init().unwrap_or(());

  + let mut child = unsafe { libc::fork() };

  + if child == 0 {

  + // child

  +

  + let env = Env::new("/tmp/sanakirja0", 4096 * 20, 2).unwrap();

  +

  + // Mutable txn

  + let mut txn = Env::mut_txn_begin(&env).unwrap();

  + info!("started child mutable txn {:?}", txn.env.root.lock());

  + let db = create_db::<MutTxn<&Env, ()>, u64, ()>(&mut txn).unwrap();

  + debug!("db = {:?}", db.db.offset);

  + txn.set_root(0, db.db.offset);

  + std::thread::sleep(std::time::Duration::from_secs(2));

  + txn.commit().unwrap();

  + info!("committed");

  + let t = std::time::SystemTime::now();

  + let mut txn = Env::mut_txn_begin(&env).unwrap();

  + // Since the parent has an immutable transaction started, we

  + // need to wait for at least some time (1s - 100ms of

  + // synchronisation margin).

  + assert!(t.elapsed().unwrap() >= std::time::Duration::from_millis(900));

  + info!("started child mutable txn {:?}", txn.env.root.lock());

  + let db = create_db::<MutTxn<&Env, ()>, u64, ()>(&mut txn).unwrap();

  + debug!("db = {:?}", db.db.offset);

  + txn.set_root(0, db.db.offset);

  + std::thread::sleep(std::time::Duration::from_secs(1));

  + txn.commit().unwrap();

  +

  + unsafe { libc::exit(0) }

  + } else {

  + // parent

  + std::thread::sleep(std::time::Duration::from_secs(1));

  +

  + let env = Env::new("/tmp/sanakirja0", 4096 * 20, 2).unwrap();

  +

  + // Immutable

  + info!("starting parent txn {:?}", env.root);

  + let txn = Env::txn_begin(&env).unwrap();

  + info!("started parent txn");

  + std::thread::sleep(std::time::Duration::from_secs(3));

  + std::mem::drop(txn);

  +

  + unsafe { libc::wait(&mut child) };

  + }
• edit in sanakirja/src/tests.rs at line 388
  [3.12573]

  [2.2354]
  + debug!("{:?}", txn.free);

  + check_free(&mut txn, &refs);
• replacement in sanakirja/src/tests.rs at line 391
  [2.2378]→[2.2378:2433](∅→∅)
  − println!("sized length = {:?}", txn.length >> 12);
  [2.2378]

  [3.412]
  + let len = txn.length >> 12;

  + println!("sized length = {:?}", len);
• replacement in sanakirja/src/tests.rs at line 407
  [3.760]→[2.2493:2550](∅→∅)
  − println!("unsized length = {:?}", txn.length >> 12);
  [3.760]

  [3.12890]
  + println!("unsized length = {:?}", (txn.length >> 12) - len);

  + add_refs(&txn, &db, &mut refs).unwrap();

  + for (p, r) in refs.iter() {

  + if *r >= 2 {

  + error!("{:?} referenced twice", p);

  + err += 1

  + }

  + }

  + assert_eq!(err, 0);

  + check_free(&mut txn, &refs);
• edit in sanakirja/src/environment/muttxn.rs at line 38
  [3.81081]

  [3.148]
  + debug!("unlock exclusive {:?}", *root);
• replacement in sanakirja/src/environment/muttxn.rs at line 145
  [3.84183]→[3.27474:27536](∅→∅),[3.3434]→[3.84279:84354](∅→∅),[3.27536]→[3.84279:84354](∅→∅),[3.84279]→[3.84279:84354](∅→∅),[3.84354]→[3.37493:37523](∅→∅),[3.37523]→[3.84381:84510](∅→∅),[3.84381]→[3.84381:84510](∅→∅),[3.84510]→[3.52979:53114](∅→∅),[3.53114]→[3.84560:84575](∅→∅),[3.84560]→[3.84560:84575](∅→∅)
  − let mut free_db: btree::Db<u64, ()> = btree::Db {

  − db: std::mem::replace(

  − &mut self.free,

  − CowPage {

  − data: std::ptr::null_mut(),

  − offset: 0,

  − },

  − ),

  − k: std::marker::PhantomData,

  − v: std::marker::PhantomData,

  − p: std::marker::PhantomData,

  − };
  [3.84183]

  [3.84575]
  + let mut free_db: btree::Db<u64, ()> =

  + btree::Db::from_page(std::mem::replace(&mut self.free, CowPage::null()));
• edit in sanakirja/src/environment/muttxn.rs at line 164
  [3.85506]

  [3.85506]
  + self.free = free_db.db;
• edit in sanakirja/src/environment/muttxn.rs at line 178
  [3.85777]→[3.85777:85828](∅→∅)
  − *root = (*root + 1) % env.roots.len();
• edit in sanakirja/src/environment/muttxn.rs at line 183
  [3.85909]

  [3.907]
  + debug!("commit: unlock {:?}", *root);
• edit in sanakirja/src/environment/muttxn.rs at line 186
  [3.1021]

  [3.1021]
  + debug!("commit: unlock file");
• edit in sanakirja/src/environment/muttxn.rs at line 190
  [3.85966]

  [3.85966]
  + *root = (*root + 1) % env.roots.len();
• edit in sanakirja/src/environment/mod.rs at line 375
  [3.4709]

  [3.105716]
  + use log::*;
• edit in sanakirja/src/environment/mod.rs at line 378
  [3.105774]

  [3.105774]
  + debug!("root lock");
• replacement in sanakirja/src/environment/mod.rs at line 381
  [3.105889]→[3.4710:4711](∅→∅)
  −
  [3.105889]

  [3.4711]
  + debug!("shared {:?}", root);

  + env_.roots[root].rw.lock_shared();
• edit in sanakirja/src/environment/mod.rs at line 384
  [3.4794]

  [3.4794]
  + debug!("old_n_txn: {:?}", old_n_txn);
• edit in sanakirja/src/environment/mod.rs at line 386
  [3.4826]→[3.4826:4877](∅→∅)
  − env_.roots[root].rw.lock_shared();
• edit in sanakirja/src/environment/mod.rs at line 387
  [3.4943]

  [3.4943]
  + debug!("file lock shared");
• edit in sanakirja/src/environment/mod.rs at line 400
  [3.106187]

  [3.5085]
  + unsafe { env.roots[self.root].rw.unlock_shared() }
• edit in sanakirja/src/environment/mod.rs at line 403
  [3.5196]→[3.5196:5259](∅→∅)
  − unsafe { env.roots[self.root].rw.unlock_shared() }
• edit in sanakirja/Cargo.toml at line 17
  [3.2944]→[3.5512:5528](∅→∅)
  − # lmdb-rs = "*"
• edit in sanakirja/Cargo.toml at line 23
  [3.108745]
  + libc = "*"

  + # lmdb-rs = "*"