sqlite: set SQLITE_THREADSAFE flag as multithreaded

[geeksilva97]

We should consider setting SQLITE_THREADSAFE as multithreaded.

node:sqlite currently runs on serialized mode. with that we pay some price on mutex acquiring/releasing. But the nature of Node allows code to work safely without these locks.

a tiny sample taken from node::sqlite::StatementExecutionHelper::ColumnToValue call

    +                             ! : | + ! 93 node::sqlite::StatementExecutionHelper::ColumnToValue(node::Environment*, sqlite3_stmt*, int, bool)  (in node) + 188  [0x102d9bef0]  node_sqlite.cc:2806
    +                             ! : | + ! : 41 sqlite3_column_bytes  (in node) + 252  [0x1043291c0]  sqlite3.c:94923
    +                             ! : | + ! : | 22 _pthread_mutex_firstfit_unlock_slow  (in libsystem_pthread.dylib) + 196,140,...  [0x188ee2050,0x188ee2018,...]
    +                             ! : | + ! : | 8 _pthread_mutex_unlock_init_slow  (in libsystem_pthread.dylib) + 20,72,...  [0x188ee1efc,0x188ee1f30,...]
    +                             ! : | + ! : | 6 DYLD-STUB$$pthread_mutex_unlock  (in node) + 4  [0x1052ca31c]
    +                             ! : | + ! : | 5 pthread_mutex_unlock  (in libsystem_pthread.dylib) + 12  [0x188ee1e24]
    +                             ! : | + ! : 16 sqlite3_column_bytes  (in node) + 48  [0x1043290f4]  sqlite3.c:94922
    +                             ! : | + ! : | 11 _pthread_mutex_firstfit_lock_slow  (in libsystem_pthread.dylib) + 148,48,...  [0x188ee1d74,0x188ee1d10,...]
    +                             ! : | + ! : | 3 pthread_mutex_lock  (in libsystem_pthread.dylib) + 12,172  [0x188ee18e0,0x188ee1980]
    +                             ! : | + ! : | 2 _pthread_mutex_lock_init_slow  (in libsystem_pthread.dylib) + 100  [0x188ee1a40]
    +                             ! : | + ! : 13 sqlite3_column_bytes  (in node) + 48,124,...  [0x1043290f4,0x104329140,...]  sqlite3.c:94922
    +                             ! : | + ! : 5 sqlite3_column_bytes  (in node) + 200,232  [0x10432918c,0x1043291ac]  sqlite3.c:94923
    +                             ! : | + ! : 4 _pthread_mutex_firstfit_lock_slow  (in libsystem_pthread.dylib) + 308  [0x188ee1e14]
    +                             ! : | + ! : 4 _pthread_mutex_lock_init_slow  (in libsystem_pthread.dylib) + 116,112  [0x188ee1a50,0x188ee1a4c]
    +                             ! : | + ! : 4 pthread_mutex_lock  (in libsystem_pthread.dylib) + 176  [0x188ee1984]
    +                             ! : | + ! : 3 _pthread_mutex_unlock_init_slow  (in libsystem_pthread.dylib) + 104,108  [0x188ee1f50,0x188ee1f54]
    +                             ! : | + ! : 2 sqlite3_column_bytes  (in node) + 4  [0x1043290c8]  sqlite3.c:94921
    +                             ! : | + ! : 1 pthread_mutex_unlock  (in libsystem_pthread.dylib) + 156  [0x188ee1eb4]
    +                             ! : | + ! 92 node::sqlite::StatementExecutionHelper::ColumnToValue(node::Environment*, sqlite3_stmt*, int, bool)  (in node) + 260  [0x102d9bf38]  node_sqlite.cc:2806
    +                             ! : | + ! : 32 sqlite3_column_bytes  (in node) + 252  [0x1043291c0]  sqlite3.c:94923
    +                             ! : | + ! : | 23 _pthread_mutex_firstfit_unlock_slow  (in libsystem_pthread.dylib) + 196,140,...  [0x188ee2050,0x188ee2018,...]
    +                             ! : | + ! : | 5 _pthread_mutex_unlock_init_slow  (in libsystem_pthread.dylib) + 20,24  [0x188ee1efc,0x188ee1f00]
    +                             ! : | + ! : | 4 pthread_mutex_unlock  (in libsystem_pthread.dylib) + 12  [0x188ee1e24]
    +                             ! : | + ! : 21 sqlite3_column_bytes  (in node) + 48  [0x1043290f4]  sqlite3.c:94922
    +                             ! : | + ! : | 11 _pthread_mutex_firstfit_lock_slow  (in libsystem_pthread.dylib) + 148,48,...  [0x188ee1d74,0x188ee1d10,...]
    +                             ! : | + ! : | 5 _pthread_mutex_lock_init_slow  (in libsystem_pthread.dylib) + 24,100  [0x188ee19f4,0x188ee1a40]
    +                             ! : | + ! : | 3 DYLD-STUB$$pthread_mutex_lock  (in node) + 4  [0x1052ca304]
    +                             ! : | + ! : | 2 pthread_mutex_lock  (in libsystem_pthread.dylib) + 12  [0x188ee18e0]
    +                             ! : | + ! : 14 sqlite3_column_bytes  (in node) + 48,40,...  [0x1043290f4,0x1043290ec,...]  sqlite3.c:94922
    +                             ! : | + ! : 6 _pthread_mutex_unlock_init_slow  (in libsystem_pthread.dylib) + 108,104  [0x188ee1f54,0x188ee1f50]
    +                             ! : | + ! : 5 pthread_mutex_unlock  (in libsystem_pthread.dylib) + 156  [0x188ee1eb4]
    +                             ! : | + ! : 5 sqlite3_column_bytes  (in node) + 192,232,...  [0x104329184,0x1043291ac,...]  sqlite3.c:94923
    +                             ! : | + ! : 4 pthread_mutex_lock  (in libsystem_pthread.dylib) + 176  [0x188ee1984]
    +                             ! : | + ! : 3 _pthread_mutex_firstfit_lock_slow  (in libsystem_pthread.dylib) + 308  [0x188ee1e14]
    +                             ! : | + ! : 1 _pthread_mutex_lock_init_slow  (in libsystem_pthread.dylib) + 116  [0x188ee1a50]

By setting threading mode to multithreaded we have less overhead over serialized. I compiled and benchmarked (on a 14-core Apple M4).

Node.js Benchmark comparison

                                                                                                                                                              confidence improvement accuracy (*)   (**)   (***)
sqlite/sqlite-is-transaction.js transaction='false' n=10000000                                                                                                               -0.69 %       ±6.17% ±8.21% ±10.69%
sqlite/sqlite-is-transaction.js transaction='true' n=10000000                                                                                                                -0.45 %       ±0.46% ±0.61%  ±0.80%
sqlite/sqlite-prepare-insert.js statement='INSERT INTO all_column_types (text_column, integer_column, real_column, blob_column) VALUES (?, ?, ?, ?)' n=100000        ***     10.29 %       ±1.73% ±2.31%  ±3.00%
sqlite/sqlite-prepare-insert.js statement='INSERT INTO blob_column_type (blob_column) VALUES (?)' n=100000                                                           ***      8.34 %       ±2.17% ±2.89%  ±3.76%
sqlite/sqlite-prepare-insert.js statement='INSERT INTO integer_column_type (integer_column) VALUES (?)' n=100000                                                     ***      6.36 %       ±1.57% ±2.09%  ±2.72%
sqlite/sqlite-prepare-insert.js statement='INSERT INTO large_text (text_8kb_column) VALUES (?)' n=100000                                                             ***      2.38 %       ±1.12% ±1.48%  ±1.93%
sqlite/sqlite-prepare-insert.js statement='INSERT INTO missing_required_value (any_value, required_value) VALUES (?, ?)' n=100000                                    ***      1.85 %       ±0.75% ±1.00%  ±1.30%
sqlite/sqlite-prepare-insert.js statement='INSERT INTO real_column_type (real_column) VALUES (?)' n=100000                                                           ***      7.47 %       ±1.52% ±2.03%  ±2.64%
sqlite/sqlite-prepare-insert.js statement='INSERT INTO text_column_type (text_column) VALUES (?)' n=100000                                                           ***      6.80 %       ±1.52% ±2.02%  ±2.65%
sqlite/sqlite-prepare-select-all-options.js options='none' statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                       ***     24.24 %       ±1.12% ±1.49%  ±1.94%
sqlite/sqlite-prepare-select-all-options.js options='none' statement='SELECT * FROM foo LIMIT 100' tableSeedSize=100000 n=100000                                     ***     26.79 %       ±0.80% ±1.07%  ±1.39%
sqlite/sqlite-prepare-select-all-options.js options='readBigInts' statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                ***     23.56 %       ±1.17% ±1.57%  ±2.05%
sqlite/sqlite-prepare-select-all-options.js options='readBigInts' statement='SELECT * FROM foo LIMIT 100' tableSeedSize=100000 n=100000                              ***     26.21 %       ±0.62% ±0.82%  ±1.07%
sqlite/sqlite-prepare-select-all-options.js options='readBigInts|returnArrays' statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                   ***     25.59 %       ±1.42% ±1.89%  ±2.48%
sqlite/sqlite-prepare-select-all-options.js options='readBigInts|returnArrays' statement='SELECT * FROM foo LIMIT 100' tableSeedSize=100000 n=100000                 ***     33.95 %       ±0.76% ±1.02%  ±1.32%
sqlite/sqlite-prepare-select-all-options.js options='returnArrays' statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                               ***     26.55 %       ±1.20% ±1.60%  ±2.09%
sqlite/sqlite-prepare-select-all-options.js options='returnArrays' statement='SELECT * FROM foo LIMIT 100' tableSeedSize=100000 n=100000                             ***     36.24 %       ±1.29% ±1.72%  ±2.24%
sqlite/sqlite-prepare-select-all.js statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                                              ***     24.52 %       ±1.39% ±1.85%  ±2.42%
sqlite/sqlite-prepare-select-all.js statement='SELECT * FROM foo LIMIT 100' tableSeedSize=100000 n=100000                                                            ***     25.94 %       ±1.12% ±1.50%  ±1.98%
sqlite/sqlite-prepare-select-all.js statement='SELECT 1' tableSeedSize=100000 n=100000                                                                               ***     18.60 %       ±1.95% ±2.61%  ±3.41%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_8kb_column FROM foo_large LIMIT 1' tableSeedSize=100000 n=100000                                          ***      7.53 %       ±1.43% ±1.91%  ±2.50%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_8kb_column FROM foo_large LIMIT 100' tableSeedSize=100000 n=100000                                        ***      3.54 %       ±0.50% ±0.66%  ±0.86%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_column FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                                    ***     19.81 %       ±1.62% ±2.17%  ±2.83%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_column FROM foo LIMIT 100' tableSeedSize=100000 n=100000                                                  ***     25.97 %       ±0.56% ±0.75%  ±0.99%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_column, integer_column FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                    ***     24.80 %       ±1.43% ±1.91%  ±2.49%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_column, integer_column FROM foo LIMIT 100' tableSeedSize=100000 n=100000                                  ***     34.32 %       ±0.40% ±0.54%  ±0.70%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_column, integer_column, real_column FROM foo LIMIT 1' tableSeedSize=100000 n=100000                       ***     25.70 %       ±1.54% ±2.05%  ±2.69%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_column, integer_column, real_column FROM foo LIMIT 100' tableSeedSize=100000 n=100000                     ***     37.77 %       ±0.50% ±0.66%  ±0.86%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_column, integer_column, real_column, blob_column FROM foo LIMIT 1' tableSeedSize=100000 n=100000          ***     22.16 %       ±1.26% ±1.67%  ±2.18%
sqlite/sqlite-prepare-select-all.js statement='SELECT text_column, integer_column, real_column, blob_column FROM foo LIMIT 100' tableSeedSize=100000 n=100000        ***     26.01 %       ±0.67% ±0.90%  ±1.17%
sqlite/sqlite-prepare-select-get-options.js options='none' statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                       ***     25.02 %       ±0.96% ±1.28%  ±1.66%
sqlite/sqlite-prepare-select-get-options.js options='readBigInts' statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                ***     23.22 %       ±1.14% ±1.52%  ±1.98%
sqlite/sqlite-prepare-select-get-options.js options='readBigInts|returnArrays' statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                   ***     27.94 %       ±1.45% ±1.93%  ±2.52%
sqlite/sqlite-prepare-select-get-options.js options='returnArrays' statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                               ***     27.08 %       ±1.21% ±1.61%  ±2.10%
sqlite/sqlite-prepare-select-get.js statement='SELECT * FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                                              ***     24.01 %       ±1.02% ±1.36%  ±1.78%
sqlite/sqlite-prepare-select-get.js statement='SELECT 1' tableSeedSize=100000 n=100000                                                                               ***     18.58 %       ±1.87% ±2.49%  ±3.24%
sqlite/sqlite-prepare-select-get.js statement='SELECT text_8kb_column FROM foo_large LIMIT 1' tableSeedSize=100000 n=100000                                          ***      8.19 %       ±1.15% ±1.53%  ±1.99%
sqlite/sqlite-prepare-select-get.js statement='SELECT text_column FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                                    ***     18.05 %       ±1.35% ±1.80%  ±2.35%
sqlite/sqlite-prepare-select-get.js statement='SELECT text_column, integer_column FROM foo LIMIT 1' tableSeedSize=100000 n=100000                                    ***     24.16 %       ±1.06% ±1.41%  ±1.83%
sqlite/sqlite-prepare-select-get.js statement='SELECT text_column, integer_column, real_column FROM foo LIMIT 1' tableSeedSize=100000 n=100000                       ***     26.91 %       ±1.49% ±1.99%  ±2.60%
sqlite/sqlite-prepare-select-get.js statement='SELECT text_column, integer_column, real_column, blob_column FROM foo LIMIT 1' tableSeedSize=100000 n=100000          ***     24.34 %       ±1.14% ±1.51%  ±1.97%

Be aware that when doing many comparisons the risk of a false-positive result increases.
In this case, there are 41 comparisons, you can thus expect the following amount of false-positive results:
  2.05 false positives, when considering a   5% risk acceptance (*, **, ***),
  0.41 false positives, when considering a   1% risk acceptance (**, ***),
  0.04 false positives, when considering a 0.1% risk acceptance (***)

Running the better-sqlite benchmark we also see the gap reduction.

better-sqlite itself has threading mode as multithreaded.

[nodejs-github-bot]

Review requested:

• @nodejs/gyp
• @nodejs/security-wg
• @nodejs/sqlite

[Renegade334]

We do backup operations off-thread, is this not going to be an issue?

no single database connection nor any object derived from database connection, such as a prepared statement, is used in two or more threads at the same time.

[geeksilva97]

We do backup operations off-thread, is this not going to be an issue?

no single database connection nor any object derived from database connection, such as a prepared statement, is used in two or more threads at the same time.

That's correct. We would need to redefine it. Either opening a new connection or making it work in the main thread. Both with advantages and drawbacks.

I will fill an issue so we can discuss more about it. So far I'm inclined to think that the gains on more use features (get, all, and such) pays off. But I might be missing something.