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fix: allocate SQL on the heap in Database.run and Database.prepare - #639
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Both passed the SQL to SQLite as a cwrap string, which Emscripten copies onto the 5 MB WebAssembly stack. SQL longer than that overwrote memory and left the database unusable. exec() and the statement iterator already allocate the SQL on the heap, so do the same here.
lovasoa
approved these changes
Oct 14, 2026
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Fixes #482
Database.runandDatabase.preparepass the SQL to SQLite as a cwrap"string"argument, which Emscripten copies onto the 5 MB WebAssembly stack. SQL longer than that writes past the stack, so the call throwsmemory access out of boundsand every later sql.js call fails too. People hit this running a largeINSERTor a SQL dump throughdb.run.execandStatementIteratoralready put the SQL on the heap withstringToNewUTF8and free it in afinally.run(the no-params path) andpreparenow do the same, and I dropped the string-typedsqlite3_prepare_v2wrapper since nothing uses it.Added
test_issue482.js, which runs a 6 MiBINSERTthroughrun,runwith params andprepare.npm testpasses.Assisted by Claude/Codex.