Skip to content

fix(agentdb): cache prepared statements to plug sql.js leak #144

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
ruvnet merged 1 commit into from
May 2, 2026
Merged

fix(agentdb): cache prepared statements to plug sql.js leak #144

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
88 changes: 59 additions & 29 deletions packages/agentdb/src/db-fallback.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,13 @@ function createSqlJsWrapper(SQL: any) {
private filename: string;
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- sql.js Statement instances
private activeStatements: Map<number, any> = new Map();
// Cache wrappers by SQL text so repeated db.prepare(sameSql) returns the
// same underlying sql.js Statement and doesn't add a new entry to
// activeStatements. Without this, callers using the
// db.prepare(sql).run(...)-and-discard pattern (idiomatic in
// better-sqlite3, where V8 GCs the handle) leak forever under sql.js.
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- prepared-statement wrapper objects
private statementCache: Map<string, any> = new Map();
private statementCounter: number = 0;
private intervalId: NodeJS.Timeout | null = null;

Expand Down Expand Up @@ -92,14 +99,31 @@ function createSqlJsWrapper(SQL: any) {
}

prepare(sql: string) {
// Reuse the cached wrapper for an identical SQL string. The cache owns
// the underlying stmt's lifetime; finalize() is a no-op on a cached
// wrapper so concurrent callers that all called prepare(sql) keep
// working. close() drops everything.
const cached = this.statementCache.get(sql);
if (cached) return cached;

const stmt = this.db.prepare(sql);
let isFinalized = false;
const stmtId = ++this.statementCounter;
const self = this;

// Track active statement
this.activeStatements.set(stmtId, stmt);

return {
const evictOnError = () => {
if (!isFinalized) {
stmt.free();
isFinalized = true;
self.activeStatements.delete(stmtId);
self.statementCache.delete(sql);
}
};

const wrapper = {
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- sql.js bind accepts heterogeneous params
run: (...params: any[]) => {
if (isFinalized) throw new Error('Statement already finalized');
Expand All @@ -113,12 +137,7 @@ function createSqlJsWrapper(SQL: any) {
lastInsertRowid: this.db.exec('SELECT last_insert_rowid()')[0]?.values[0]?.[0] || 0
};
} catch (error) {
// Auto-free on error to prevent memory leak
if (!isFinalized) {
stmt.free();
isFinalized = true;
this.activeStatements.delete(stmtId);
}
evictOnError();
throw error;
}
},
Expand Down Expand Up @@ -146,12 +165,7 @@ function createSqlJsWrapper(SQL: any) {

return result;
} catch (error) {
// Auto-free on error to prevent memory leak
if (!isFinalized) {
stmt.free();
isFinalized = true;
this.activeStatements.delete(stmtId);
}
evictOnError();
throw error;
}
},
Expand All @@ -178,24 +192,20 @@ function createSqlJsWrapper(SQL: any) {
stmt.reset();
return results;
} catch (error) {
// Auto-free on error to prevent memory leak
if (!isFinalized) {
stmt.free();
isFinalized = true;
this.activeStatements.delete(stmtId);
}
evictOnError();
throw error;
}
},

finalize: () => {
if (!isFinalized) {
stmt.free();
isFinalized = true;
this.activeStatements.delete(stmtId);
}
// No-op while cached: the wrapper is shared and finalize() must not
// tear out a stmt another caller is about to use. close() handles
// the real teardown.
}
};

this.statementCache.set(sql, wrapper);
return wrapper;
}

exec(sql: string) {
Expand Down Expand Up @@ -237,6 +247,7 @@ function createSqlJsWrapper(SQL: any) {
}
}
this.activeStatements.clear();
this.statementCache.clear();

// Save to file before closing
this.save();
Expand Down Expand Up @@ -299,16 +310,31 @@ export async function createDatabase(filename: string, options?: unknown): Promi
export function wrapExistingSqlJsDatabase(rawDb: any, filename: string = ':memory:'): any {
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- sql.js Statement instances
const activeStatements = new Map<number, any>();
// SQL-text cache; see SqlJsDatabase.statementCache for rationale.
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- prepared-statement wrapper objects
const statementCache = new Map<string, any>();
let statementCounter = 0;

return {
prepare(sql: string) {
const cached = statementCache.get(sql);
if (cached) return cached;

const stmt = rawDb.prepare(sql);
let isFinalized = false;
const stmtId = ++statementCounter;
activeStatements.set(stmtId, stmt);

return {
const evictOnError = () => {
if (!isFinalized) {
stmt.free();
isFinalized = true;
activeStatements.delete(stmtId);
statementCache.delete(sql);
}
};

const wrapper = {
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- sql.js bind accepts heterogeneous params
run(...params: any[]) {
if (isFinalized) throw new Error('Statement already finalized');
Expand All @@ -321,7 +347,7 @@ export function wrapExistingSqlJsDatabase(rawDb: any, filename: string = ':memor
lastInsertRowid: rawDb.exec('SELECT last_insert_rowid()')[0]?.values[0]?.[0] || 0,
};
} catch (error) {
if (!isFinalized) { stmt.free(); isFinalized = true; activeStatements.delete(stmtId); }
evictOnError();
throw error;
}
},
Expand All @@ -339,7 +365,7 @@ export function wrapExistingSqlJsDatabase(rawDb: any, filename: string = ':memor
columns.forEach((col: string, idx: number) => { result[col] = values[idx]; });
return result;
} catch (error) {
if (!isFinalized) { stmt.free(); isFinalized = true; activeStatements.delete(stmtId); }
evictOnError();
throw error;
}
},
Expand All @@ -359,14 +385,17 @@ export function wrapExistingSqlJsDatabase(rawDb: any, filename: string = ':memor
stmt.reset();
return results;
} catch (error) {
if (!isFinalized) { stmt.free(); isFinalized = true; activeStatements.delete(stmtId); }
evictOnError();
throw error;
}
},
finalize() {
if (!isFinalized) { stmt.free(); isFinalized = true; activeStatements.delete(stmtId); }
// No-op while cached; close() handles teardown.
},
};

statementCache.set(sql, wrapper);
return wrapper;
},

exec(sql: string) {
Expand All @@ -387,6 +416,7 @@ export function wrapExistingSqlJsDatabase(rawDb: any, filename: string = ':memor
try { stmt.free(); } catch { /* already freed */ }
}
activeStatements.clear();
statementCache.clear();
this.save();
rawDb.close();
},
Expand Down
Loading