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`run().changes` was the delta of `sqlite3_total_changes()`. That delta also counts the rows that triggers, foreign key actions and the shadow tables of virtual tables write. One row inserted into an FTS5 table reported 7. SQLite's own `changes()` and node:sqlite report 1. `changes` is now `sqlite3_changes64()`, with two cases that report 0. `sqlite3_changes64()` is set only by INSERT, UPDATE and DELETE, so after another statement it holds an older count: - `sqlite3_total_changes()` did not move: the statement wrote nothing, and the count is the one of the previous write. better-sqlite3 uses the same rule. - The statement is read-only: a COMMIT, SAVEPOINT or RELEASE makes FTS5 write its pending rows, so the total moves and the count is the one of that nested write. `Database#run` adds the count of each statement of a multi-statement string. `Bun.SQL` with the sqlite adapter reads `count` from `Database#run`, so it reports the same number.
WalkthroughSQLite change metadata now reports rows directly changed by statements. Execution accumulates direct changes across statements, while documentation and tests cover triggers, foreign keys, virtual tables, transactions, and no-op operations. ChangesSQLite direct change reporting
Suggested reviewers: Priority: ⬇️ Low Merge Risk: 🟡 Moderate · up to Long-lived SQLite connections that modify more than the signed-int limit can report incorrect 🚥 Pre-merge checks | ✅ 4✅ Passed checks (4 passed)
Comment |
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Status: the fix is pushed. The diff is green on every platform, and it waits for a maintainer review. How I reproduced it: I ran the script from the Notes section of the description on bun 1.4.3-canary (b52d513, linux x64) and on node v26.3.0.
On a release build of the merge base, 28 of the 32 new tests in Speed: the measurement that @alii asked for is in this comment. CI on fb2a28d (build 117907): 180 of 181 jobs pass. |
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…imit The comment said that only INSERT, UPDATE and DELETE set sqlite3_changes64(), but the helper also returns it for DDL during which a virtual table writes (CREATE VIRTUAL TABLE, or DDL in a transaction that has pending FTS5 rows). State that limit in the comment and in the JSDoc of `Changes.changes`.
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I re-reviewed the two follow-up commits and found no bugs; the shortened comment and the .d.ts note about CREATE VIRTUAL TABLE address what I raised earlier. A maintainer should still weigh this one because it changes a shipped number: changes for DML on an INSTEAD OF view drops from 1 to 0, and trigger/cascade rows stop counting.
What was reviewed:
directChangesSincegating (sqlite3_stmt_readonly+sqlite3_total_changesequality before readingsqlite3_changes64) at both call sites insrc/jsc/bindings/sqlite/JSSQLStatement.cpp; the per-statement snapshot inside theDatabase#runloop replaces the single before/after delta correctly.- The
describe.eachmatrix intest/js/bun/sqlite/sqlite.test.jscovers all four entry points plus the FTS5-flush cases for COMMIT/SAVEPOINT/RELEASE; assertions are exact values withusingcleanup. docs/runtime/sqlite.mdxstates the new semantics but omits theCREATE VIRTUAL TABLEcaveat that the.d.tsJSDoc now carries; minor, not blocking.
Extended reasoning...
Overview
The PR replaces the sqlite3_total_changes() delta used for changes in Database#run/exec and Statement#run with a helper directChangesSince that returns sqlite3_changes64() only when the statement is not read-only and sqlite3_total_changes() moved. Database#run now snapshots per statement and sums. Docs and the Changes.changes JSDoc are updated, and the follow-up commits (4df937b, b7eb1e2) shortened the helper comment to one line and added the CREATE VIRTUAL TABLE limit to the .d.ts, addressing the two optional notes from the prior run. Tests add a four-entry-point describe.each matrix plus a Bun.sql SQLite-adapter case.
Security risks
None. The change reads SQLite counters after statement execution; no user input is parsed or allocated differently, no new JS entry points, and the values flow into jsNumber as before.
Level of scrutiny
The native diff is small and each guard is exercised by tests (the PR states which tests fail when each clause is removed, and the matrix in the test file is consistent with that). What warrants a human look is not correctness but compatibility: changes is a shipped, user-visible number, and this PR intentionally changes it for triggers, cascades, virtual-table shadow writes, and INSTEAD OF views (1 to 0). That aligns with SQLite's changes(), node:sqlite and better-sqlite3, but whether Bun wants to make that break without a changelog/major note is a maintainer decision.
Other factors
The pre-existing partial-failure behaviour in the multi-statement loop (only the last statement's rc throws) is unchanged by this PR and was already noted inline in the prior run; #37418 addresses it separately. The docs .mdx does not carry the CREATE VIRTUAL TABLE caveat the JSDoc now has; that is a small doc inconsistency rather than a bug. The bug hunt ran to a dry streak with no findings.
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The re-review found no bugs. One point remains for a maintainer:
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Updated 1:02 PM PT - Sep 18th, 2026
❌ @robobun, your commit fb2a28d has 1 failures in
🧪 To try this PR locally: bunx bun-pr 43306That installs a local version of the PR into your bun-43306 --bun |
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Inline comments:
In `@src/jsc/bindings/sqlite/JSSQLStatement.cpp`:
- Around line 1473-1477: Update directChangesSince to accept an sqlite3_int64
baseline and compare it with sqlite3_total_changes64; also change both
total_changes_before baselines to sqlite3_int64 values obtained from
sqlite3_total_changes64, including the one-off and prepared-statement paths.
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docs/runtime/sqlite.mdxpackages/bun-types/sqlite.d.tssrc/jsc/bindings/sqlite/JSSQLStatement.cpptest/js/bun/sqlite/sqlite.test.jstest/js/sql/sqlite-sql.test.ts
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Deterministically measure how much slower bun:sqlite gets after these changes |
…es64 SQLite documents the result of sqlite3_total_changes() as undefined after the connection changed more rows than an int holds. The helper only compares the value for equality, so use the 64-bit API for both reads. The lazy loader gets the symbol with the same fallback as sqlite3_changes64 for SQLite older than 3.37.
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@alii I will measure it with instruction counts, not with wall-clock time. This machine has no I will compare release builds of the merge base and of this branch for |
Each read of sqlite3_total_changes64() or sqlite3_changes64() locks the connection mutex. The first version of this change read three counters for every write, one more than before, which cost 109 instructions per Statement#run call. - A read-only statement reads no counter. - A Statement that reported changes once is an INSERT, UPDATE or DELETE. Those always set sqlite3_changes64(), so later runs read only that counter. Measured in instructions per call (release build, JIT off), against the merge base: prepared INSERT or UPDATE of one row -86, SELECT through run() -187, prepared UPDATE that never changes a row +21, one-off Database#run INSERT +114 of 9740.
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@alii Measured. The first version of this PR made every prepared write 109 instructions slower per call (about 15 to 20 ns, 5 to 7% of a one-row write). I changed the code. A prepared write with bound parameters is now 84 instructions faster than the merge base. A prepared write with no bound parameters is 126 slower. Updated for fb2a28d. The first post had the numbers of f689902, which a review showed to be wrong for a reused Instructions per call (release builds, exact, the same number in every process):
Wall clock, JIT on (ns per call, minimum of 1,500 batches of 2,000 calls, 5 alternating processes per build, spread between processes below 4 ns):
Where the cost is. In the bundled SQLite 3.53, What the code does now.
What is still slower.
Method. This machine has no icount.c (tracer)// icount: run a program under ptrace and count the user-space instructions that its main thread executes
// between two marker syscalls: write(MARK_FD, buf, 1) starts a window, write(MARK_FD, buf, 2) ends it.
// Prints one line per window: "<label-index> <instructions>".
#define _GNU_SOURCE
#include <errno.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/wait.h>
#include <unistd.h>
#include <fcntl.h>
#define MARK_FD 1000
static int wait_stop(pid_t pid, int* status)
{
for (;;) {
pid_t r = waitpid(pid, status, __WALL);
if (r < 0) {
if (errno == EINTR) continue;
return -1;
}
return 0;
}
}
int main(int argc, char** argv)
{
if (argc < 2) {
fprintf(stderr, "usage: icount prog args...\n");
return 2;
}
pid_t pid = fork();
if (pid == 0) {
int nul = open("/dev/null", O_WRONLY);
dup2(nul, MARK_FD);
ptrace(PTRACE_TRACEME, 0, 0, 0);
raise(SIGSTOP);
execvp(argv[1], argv + 1);
perror("execvp");
_exit(127);
}
int status;
if (wait_stop(pid, &status) < 0) return 1;
ptrace(PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACESYSGOOD | PTRACE_O_EXITKILL);
int in_syscall = 0;
int window = 0;
int sig = 0;
for (;;) {
if (ptrace(PTRACE_SYSCALL, pid, 0, sig) < 0) break;
sig = 0;
if (wait_stop(pid, &status) < 0) break;
if (WIFEXITED(status) || WIFSIGNALED(status)) break;
if (!WIFSTOPPED(status)) continue;
int s = WSTOPSIG(status);
if (s != (SIGTRAP | 0x80)) {
if (s != SIGTRAP && s != SIGSTOP) sig = s;
continue;
}
in_syscall = !in_syscall;
if (!in_syscall) continue; // syscall exit
struct user_regs_struct regs;
ptrace(PTRACE_GETREGS, pid, 0, ®s);
if (regs.orig_rax != SYS_write || regs.rdi != MARK_FD || regs.rdx != 1) continue;
// Start marker seen at syscall entry. Let the syscall finish, then single-step.
ptrace(PTRACE_SYSCALL, pid, 0, 0);
wait_stop(pid, &status);
in_syscall = 0;
uint64_t count = 0;
int pending = 0;
for (;;) {
if (ptrace(PTRACE_SINGLESTEP, pid, 0, pending) < 0) { perror("singlestep"); return 1; }
pending = 0;
if (wait_stop(pid, &status) < 0) return 1;
if (WIFEXITED(status) || WIFSIGNALED(status)) { fprintf(stderr, "exited inside window\n"); return 1; }
int ss = WSTOPSIG(status);
if (ss != SIGTRAP && ss != (SIGTRAP | 0x80)) { pending = ss; continue; }
count++;
ptrace(PTRACE_GETREGS, pid, 0, ®s);
if ((long long)regs.orig_rax == SYS_write && regs.rdi == MARK_FD && regs.rdx == 2) break;
}
printf("%d %llu\n", window++, (unsigned long long)count);
fflush(stdout);
}
return 0;
}bench-icount.mjs (instruction windows)// Run under /tmp/icount with BUN_JSC_useJIT=0. Every window holds exactly one call.
// The tracer prints the instruction count of each window. The "empty" scenario measures the markers alone.
import { Database } from "bun:sqlite";
import fs from "node:fs";
const MARK = 1000;
const one = new Uint8Array(1);
const two = new Uint8Array(2);
const WINDOWS = Number(process.env.WINDOWS || 150);
const db = new Database(":memory:");
db.exec(`
CREATE TABLE t (a);
CREATE TABLE tt (a);
CREATE TABLE log (x);
CREATE TRIGGER tr AFTER INSERT ON tt BEGIN INSERT INTO log VALUES (new.a); END;
INSERT INTO t VALUES (0);
`);
const noop = db.prepare("UPDATE t SET a = 1 WHERE 0");
const insert = db.prepare("INSERT INTO t VALUES (?)");
const insertTrigger = db.prepare("INSERT INTO tt VALUES (?)");
const update = db.prepare("UPDATE t SET a = ? WHERE rowid = 1");
const select = db.prepare("SELECT 1");
const updateNoParams = db.prepare("UPDATE t SET a = a + 1 WHERE rowid = 1");
const scenarios = [
["empty window (markers only)", () => {}],
["Statement#run: UPDATE that changes no row", () => noop.run()],
["Statement#run: SELECT 1", () => select.run()],
["Statement#run: UPDATE one row by rowid", i => update.run(i)],
["Statement#run: UPDATE one row, no bound parameters", () => updateNoParams.run()],
["Statement#run: INSERT one row", i => insert.run(i)],
["Statement#run: INSERT one row, trigger inserts one more", i => insertTrigger.run(i)],
["Database#run: UPDATE that changes no row", () => db.run("UPDATE t SET a = 1 WHERE 0")],
["Database#run: INSERT one row", () => db.run("INSERT INTO t VALUES (1)")],
];
db.run("BEGIN");
for (const [, fn] of scenarios) {
for (let i = 0; i < 50; i++) fn(i);
Bun.gc(true);
for (let i = 0; i < WINDOWS; i++) {
fs.writeSync(MARK, one);
fn(i);
fs.writeSync(MARK, two);
}
}
db.run("COMMIT");
console.log(JSON.stringify({ labels: scenarios.map(s => s[0]), windows: WINDOWS }));Run: bench-time3.mjs (wall clock)// Wall-clock check with the JIT on. Many short batches, so that the minimum finds an undisturbed time slice.
import { Database } from "bun:sqlite";
const CALLS = 2000;
const BATCHES = Number(process.env.BATCHES || 1500);
function bench(setupSql, sql, args) {
const db = new Database(":memory:");
if (setupSql) db.run(setupSql);
const stmt = db.prepare(sql);
db.run("BEGIN");
for (let i = 0; i < 100000; i++) args ? stmt.run(i) : stmt.run();
db.run("ROLLBACK");
let best = Infinity;
for (let b = 0; b < BATCHES; b++) {
db.run("BEGIN");
const start = Bun.nanoseconds();
if (args) for (let i = 0; i < CALLS; i++) stmt.run(i);
else for (let i = 0; i < CALLS; i++) stmt.run();
const ns = (Bun.nanoseconds() - start) / CALLS;
db.run("ROLLBACK");
if (ns < best) best = ns;
}
db.close();
return best;
}
console.log(
JSON.stringify({
insert: bench("CREATE TABLE t (a)", "INSERT INTO t VALUES (?)", true),
update: bench("CREATE TABLE t (a); INSERT INTO t VALUES (0)", "UPDATE t SET a = ? WHERE rowid = 1", true),
updateNoParams: bench("CREATE TABLE t (a); INSERT INTO t VALUES (0)", "UPDATE t SET a = a + 1 WHERE rowid = 1", false),
noop: bench("CREATE TABLE t (a)", "UPDATE t SET a = 1 WHERE 0", false),
select: bench("", "SELECT 1", false),
}),
); |
…parameters A Statement that reported changes once kept reading only sqlite3_changes64(). That is wrong for a schema statement that counts rows in one run and is a no-op in the next: with foreign keys on, `DROP TABLE IF EXISTS parent` counts its implicit DELETE, and the second run of the same cached Statement reported the count of an unrelated write. SQLite rejects bound parameters in DDL and in PRAGMA, so a statement that has them and changed rows is an INSERT, UPDATE or DELETE. Only such a statement takes the one-counter path. Other statements compare sqlite3_total_changes64() on every run.
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Differential check of fb2a28d against node:sqlite (node v26.3.0), with seeded programs that I generated for this PR. Result: 800 programs of 80 steps each (64,000 steps, 20,171 of them The masked class is a What the programs cover:
storm.mjs// Differential storm for `changes`: the same seeded programs run under bun (bun:sqlite) and node (node:sqlite).
// Usage: <runtime> storm.mjs <firstSeed> <count> <stepsPerProgram>
const isBun = typeof Bun !== "undefined";
const [firstSeed, count, steps] = process.argv.slice(2).map(Number);
function rng(seed) {
let s = (seed * 2654435761) >>> 0 || 1;
return () => {
s ^= s << 13;
s >>>= 0;
s ^= s >>> 17;
s ^= s << 5;
s >>>= 0;
return s / 4294967296;
};
}
const { Database } = isBun ? await import("bun:sqlite") : {};
const { DatabaseSync } = isBun ? {} : await import("node:sqlite");
function open() {
const db = isBun ? new Database(":memory:") : new DatabaseSync(":memory:");
const cache = new Map();
const prepare = sql => {
let stmt = cache.get(sql);
if (!stmt) cache.set(sql, (stmt = db.prepare(sql)));
return stmt;
};
let depth = 0;
const transaction = fn => {
if (isBun) return db.transaction(fn);
return () => {
const d = depth++;
db.exec(d === 0 ? "BEGIN" : `SAVEPOINT sp${d}`);
try {
const r = fn();
db.exec(d === 0 ? "COMMIT" : `RELEASE sp${d}`);
return r;
} catch (e) {
db.exec(d === 0 ? "ROLLBACK" : `ROLLBACK TO sp${d}; RELEASE sp${d}`);
throw e;
} finally {
depth--;
}
};
};
return { db, prepare, transaction };
}
function program(seed) {
const rand = rng(seed);
const int = n => Math.floor(rand() * n);
const pick = arr => arr[int(arr.length)];
const { db, prepare, transaction } = open();
const withTrigger = rand() < 0.4;
const withCascade = rand() < 0.5;
db.exec(`
PRAGMA foreign_keys = ON;
CREATE TABLE t1 (id INTEGER PRIMARY KEY, a, b UNIQUE);
CREATE TABLE t2 (id INTEGER PRIMARY KEY, t1_id REFERENCES t1 (id) ${withCascade ? "ON DELETE CASCADE" : "ON DELETE SET NULL"}, v);
CREATE TABLE t3 (k TEXT PRIMARY KEY, v) WITHOUT ROWID;
CREATE TABLE log (x);
CREATE VIRTUAL TABLE ft USING fts5(a, b);
CREATE VIRTUAL TABLE rt USING rtree(id, x0, x1);
CREATE TABLE docs (id INTEGER PRIMARY KEY, body);
CREATE VIRTUAL TABLE docs_fts USING fts5(body, content='docs', content_rowid='id');
CREATE TRIGGER docs_ai AFTER INSERT ON docs BEGIN INSERT INTO docs_fts(rowid, body) VALUES (new.id, new.body); END;
CREATE TRIGGER docs_ad AFTER DELETE ON docs BEGIN INSERT INTO docs_fts(docs_fts, rowid, body) VALUES ('delete', old.id, old.body); END;
${withTrigger ? "CREATE TRIGGER tr1 AFTER INSERT ON t1 BEGIN INSERT INTO log VALUES (new.id); END; CREATE TRIGGER tr2 AFTER UPDATE ON t1 BEGIN INSERT INTO log VALUES (new.id); INSERT INTO log VALUES (-new.id); END;" : ""}
`);
const out = [];
// Under bun, half of the writes go through the one-off Database#run path. node always uses a prepared statement.
const run = (sql, ...params) => {
const oneOff = rand() < 0.5;
if (isBun && oneOff) return Number(db.run(sql, ...params).changes);
return Number(prepare(sql).run(...params).changes);
};
// Two statements in one string: bun sums them in Database#run, node runs them one after the other.
const runTwo = (first, second) => {
if (isBun) return Number(db.run(first + "; " + second + ";").changes);
return Number(prepare(first).run().changes) + Number(prepare(second).run().changes);
};
const writes = [
() => ["insert", run("INSERT INTO t1 (a, b) VALUES (?, ?)", int(100), int(60))],
() => ["insert2", run("INSERT INTO t1 (a, b) VALUES (?, ?), (?, ?)", int(100), 1000 + int(100000), int(100), 200000 + int(100000))],
() => ["insertIgnore", run("INSERT OR IGNORE INTO t1 (a, b) VALUES (?, ?)", int(100), int(60))],
() => ["insertReplace", run("INSERT OR REPLACE INTO t1 (id, a, b) VALUES (?, ?, ?)", 1 + int(30), int(100), 300000 + int(100000))],
() => ["upsertUpdate", run("INSERT INTO t1 (a, b) VALUES (?, ?) ON CONFLICT (b) DO UPDATE SET a = excluded.a", int(100), int(60))],
() => ["upsertNothing", run("INSERT INTO t1 (a, b) VALUES (?, ?) ON CONFLICT (b) DO NOTHING", int(100), int(60))],
() => ["insertChild", run("INSERT INTO t2 (t1_id, v) SELECT id, ? FROM t1 WHERE id <= ?", int(9), int(12))],
() => ["update", run("UPDATE t1 SET a = ? WHERE id BETWEEN ? AND ?", int(100), int(40), int(40))],
() => ["updateNoParams", run("UPDATE t1 SET a = a + 1 WHERE id % 3 = 0")],
() => ["updateMiss", run("UPDATE t1 SET a = ? WHERE id = ?", int(100), 100000 + int(10))],
() => ["delete", run("DELETE FROM t1 WHERE id = ?", 1 + int(30))],
() => ["deleteRange", run("DELETE FROM t1 WHERE id > ? AND id < ?", int(40), int(40))],
() => ["deleteAllChildren", run("DELETE FROM t2")],
() => ["kv", run("INSERT INTO t3 VALUES (?, ?) ON CONFLICT (k) DO UPDATE SET v = excluded.v", "k" + int(8), int(100))],
() => ["kvDelete", run("DELETE FROM t3 WHERE k = ?", "k" + int(12))],
() => ["ftsInsert", run("INSERT INTO ft VALUES (?, ?)", "w" + int(50) + " w" + int(50), "x" + int(9))],
() => ["ftsInsert2", run("INSERT INTO ft VALUES (?, ?), (?, ?)", "w" + int(50), "y", "w" + int(50), "z")],
() => ["ftsUpdate", run("UPDATE ft SET b = ? WHERE rowid <= ?", "u" + int(9), int(6))],
() => ["ftsDelete", run("DELETE FROM ft WHERE rowid = ?", 1 + int(20))],
() => ["ftsDeleteNoParams", run("DELETE FROM ft WHERE rowid % 7 = 0")],
() => ["ftsMatchSelectRun", run("SELECT count(*) FROM ft WHERE ft MATCH ?", "w" + int(50))],
() => ["rtInsert", run("INSERT OR REPLACE INTO rt VALUES (?, ?, ?)", 1 + int(40), int(10), 10 + int(10))],
() => ["rtDelete", run("DELETE FROM rt WHERE id <= ?", int(8))],
() => ["docsInsert", run("INSERT INTO docs (body) VALUES (?)", "doc w" + int(50))],
() => ["docsDelete", run("DELETE FROM docs WHERE id = ?", 1 + int(25))],
() => ["twoStatements", runTwo("INSERT INTO t3 VALUES ('m" + int(1000000) + "', 1) ON CONFLICT (k) DO NOTHING", "UPDATE t1 SET a = a + 1 WHERE id % 5 = 0")],
() => ["twoStatementsSelectLast", runTwo("DELETE FROM t1 WHERE id = " + (1 + int(30)), "SELECT 1")],
() => ["withDelete", run("WITH old AS (SELECT id FROM t1 WHERE id < ?) DELETE FROM t1 WHERE id IN (SELECT id FROM old)", int(6))],
];
const guarded = f => {
try {
return f();
} catch (e) {
return ["throw", String(e.code ?? e.message).slice(0, 40)];
}
};
const txBody = nestedAllowed => {
const results = [];
const n = 1 + int(4);
for (let i = 0; i < n; i++) {
if (nestedAllowed && rand() < 0.25) {
const inner = transaction(() => txBody(false));
try {
results.push(["nested", inner()]);
} catch (e) {
results.push(["nestedThrow", String(e.code ?? e.message).slice(0, 40)]);
}
} else if (rand() < 0.12) {
// a write that can fail on the UNIQUE column, not guarded: it aborts this transaction level
results.push(["dup", run("INSERT INTO t1 (a, b) VALUES (?, ?)", int(100), int(8))]);
} else {
results.push(pick(writes)());
}
}
return results;
};
for (let i = 0; i < steps; i++) {
const r = rand();
if (r < 0.55) out.push(guarded(pick(writes)));
else if (r < 0.65) out.push(["select", run("SELECT count(*) FROM t1 WHERE a > ?", int(100))]);
else out.push(guarded(() => ["tx", transaction(() => txBody(true))()]));
}
db.close();
return out;
}
for (let seed = firstSeed; seed < firstSeed + count; seed++) {
const out = program(seed);
for (let i = 0; i < out.length; i++) console.log(`${seed}\t${i}\t${JSON.stringify(out[i])}`);
}Run: |
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3 participants
Problem
run().changescounts rows that the statement did not change itself. A one-rowUPDATEwith anupdated_attrigger reports 2. A one-row FTS5 insert reports 7. SQLite'schanges(), node:sqlite and better-sqlite3 report 1, so achanges === 1check fails.jsSQLStatementExecuteFunctionandjsSQLStatementExecuteStatementFunctionRun(src/jsc/bindings/sqlite/JSSQLStatement.cpp) report the delta ofsqlite3_total_changes(), which includes every write the statement causes elsewhere.Fix
changesissqlite3_changes64(), or 0 when the statement is read-only orsqlite3_total_changes64()did not move. In those cases the counter holds an older count (the previous write, or the FTS5 flush of aCOMMIT), soSELECT,CREATE TABLEandCOMMITstill report 0.Database#runsums its statements.Bun.SQL(sqlite) getscountfrom it.Statementwith bound parameters that changed rows once is DML and reads onlysqlite3_changes64(): -84 instructions per call against the merge base. A prepared write with no bound parameter costs +126 (measurement).INSTEAD OFview reports 0 (was 1), as SQLite documents. The delta ofSELECT total_changes()around the call gives the old number.test/js/bun/sqlite/sqlite.test.js(32 new tests, 28 fail without the fix),test/js/sql/sqlite-sql.test.ts(1 new test), all oftest/js/bun/sqlite/. Self-reviewed, one known limit remains (Notes).Background
sqlite3_total_changes64()counts every row written on the connection, including trigger and foreign key rows.sqlite3_changes64()is the row count of the most recentINSERT,UPDATEorDELETE. Other statements do not reset it.COMMIT.Supersedes #34916 (closed as stale, no review). Found by a differential fuzzer against node:sqlite. No user issue exists.
Notes
Repro (runs under bun and under node 22+):
changes, statement by statement (bun 1.4.3-canary b52d513, this branch, node v26.3.0):changes()UPDATE1 row,updated_attriggerBEGINCOMMITof that transactiondb.run("BEGIN; INSERT INTO ft ...; COMMIT;")'optimize'/'rebuild'commandDROP TABLE parent(3 rows, foreign keys on, 3 children cascade)INSTEAD OFtriggerREPLACE, upsert,INSERT ... RETURNING,INSERT OR IGNORE, temp and attached tables,WITHOUT ROWIDSELECT,CREATE TABLE,BEGIN,COMMITafter a writedb.run("INSERT 1 row; INSERT 2 rows; SELECT"), trigger on the tableThe old number also depended on the transaction mode: the FTS5 insert above reports 7 in autocommit mode, and 3 plus 4 on the
COMMITinside a transaction.History.
changesshipped in #11887 for #2608 and #8284. Both asked for the better-sqlite3 shape ofrun(), and #2608 namedsqlite3_changes. #34916 made the same change as this PR but readsqlite3_changes64()with no check inStatement#run. ASELECTthen reported the count of the previous write, and that PR had to change thecreatestest fromchanges: 0tochanges: 1. This PR keeps 0 there, andcreatesis unchanged. The check onsqlite3_total_changes()is the rule better-sqlite3 uses. The read-only check goes one step further: better-sqlite3 and node:sqlite report 1 for aCOMMITthat flushes FTS5.Bun.SQLscope. The sqlite adapter sends a statement throughDatabase#runonly when its tokenizer decides that the statement returns no rows.INSERT ... SELECT,WITH ... INSERT/UPDATE/DELETEand DML with aSELECTtoken on its own line go throughprepare().all()and reportcount: 0before and after this PR. That is #30811, and #33583 has the fix. #40434 addsaffectedRowstoBun.SQLand reads the same number.Self-review. A review of the diff before the push found that a
COMMIT,SAVEPOINTorRELEASEthat makes FTS5 write its pending rows reported 1.db.run("BEGIN; INSERT INTO ft ...; COMMIT;")then reported 2. The read-only check indirectChangesSincefixes that. The review also asked for the Compatibility bullet, theBun.SQLscope paragraph, a narrower JSDoc sentence about multi-statement strings, and the links to the earlier PR and issues. All of these are in this PR. The one concern that stays open is the known limit below.Performance. In the bundled SQLite 3.53,
sqlite3_total_changes64()andsqlite3_changes64()lock the connection mutex (about 45 to 50 instructions and 15 ns per read). The merge base reads two counters perrun(). Now a read-only statement reads none. AStatementthat has bound parameters and changed rows once reads one: SQLite rejects bound parameters in DDL and in PRAGMA, so such a statement is anINSERT,UPDATEorDELETE, and those setsqlite3_changes64()in every run. Other statements read two, plussqlite3_changes64()when the total moved. Exact instruction counts per call against the merge base (release build, JIT off): preparedINSERTorUPDATEof one row with a bound parameter -84, the sameUPDATEwith no bound parameter +126,SELECTthroughrun()-186, preparedUPDATEthat never changes a row +25, one-offDatabase#runINSERT+114 of 9,717. Wall clock with the JIT on: preparedINSERT337.2 ns to 325.6 ns, preparedUPDATEwith no bound parameter 278.3 ns to 294.0 ns. The method and the scripts are in this comment.Known limit. SQLite has no public API that says whether a statement is an
INSERT,UPDATEorDELETE. A statement that is none of these, is not read-only, and during which a virtual table module writes, reports the count of the last nested write. Measured cases:CREATE VIRTUAL TABLE ... USING fts5reports 1 (was 3).USING rtreereports 1 (was 1).CREATE TABLE,CREATE INDEX,ALTER TABLE,DROP TABLE,CREATE VIEW,ANALYZEandREINDEXreport 1 (was 4). The statement journal makes FTS5 flush.VACUUM,PRAGMA user_versionandCREATE TRIGGERreport 0.One more corner:
CREATE TABLE IF NOT EXISTS x AS SELECT ... ?accepts a bound parameter. If an FTS5 flush runs inside it once, theStatementobject takes the one-counter path, and a later no-op run of the same object reports the last count of the connection. node:sqlite and better-sqlite3 report the same 1 in these cases. The JSDoc ofChanges.changesanddocs/runtime/sqlite.mdxstate the limit. A gate onsqlite3_column_count(), or onsqlite3_changes64() <= delta, does not separate these statements from a write. A check of the leading SQL keyword is a tokenizer over user SQL, which #33583 removes from theBun.SQLadapter for the same reason.Each clause of the fix has a test. With the
sqlite3_total_changes()check removed, 6 tests fail: the four "0 for a statement that changes no row" tests (aCREATE TABLEreports the count of the previous write) and the two "adds up the statements" tests. With the read-only check removed, 7 tests fail: the four "SAVEPOINT, RELEASE or COMMIT" tests, the two "FTS5 writes of a COMMIT" tests, and theBun.SQLtest. With the bound-parameter condition removed, the two "reused DROP TABLE Statement" tests fail with[3, 5, 5].macOS. bun:sqlite uses the system
libsqlite3.dylibthere./usr/bin/sqlite3on macOS 14.8 (SQLite 3.43.2) and macOS 26.6 (3.51.0) has FTS5 and R-Tree, and itschanges()gives the values the new tests expect.sqlite3_changes64already has a fallback tosqlite3_changesinlazy_sqlite3.hfor SQLite older than 3.37.Other notes.
sqlite3_total_changes()inDatabase#runbefore it bound parameters. The new code reads it for each statement, immediately beforesqlite3_step.Database#run(it stops at the first failed statement). The two changes are independent. The second one to merge needs a small rebase.docs/runtime/sqlite.mdxand the JSDoc ofChanges.changesnow state what counts.#13082insqlite.test.jstimes out at 5 s when the whole file runs under the debug ASAN build on my machine (it takes 6.5 s to 7 s). It does the same without this change, and it passes in 0.3 s on a release build.no test proof · iteration 2 · platform-specific test(s) that do not run on this machine, deferring to CI, which covers all platforms: test/js/bun/sqlite/sqlite.test.js