perf(db): cap error_logs.log_snippet at 16KB + v11 migration to truncate legacy rows

Author: Sentinel-Bluebuilder

core/db.js

@@ -440,6 +440,26 @@ function runMigrations(db) {
     db.prepare('UPDATE schema_version SET version = 10').run();
     })();
   }
+
+  if (current < 11) {
+    db.transaction(() => {
+    // ── Migration v11: cap error_logs.log_snippet at 16 KB ──────────────────
+    // The inline log_snippet column historically stored up to 512 KB per
+    // failure, bloating audit.db. The full log already lives on disk in the
+    // per-run audit-*.log file, so the DB only needs a readable snippet for
+    // the copy-failure UX. Going forward insertErrorLog() caps at 16384 chars
+    // from the tail; this migration truncates any legacy oversized rows to
+    // match. substr(s, length(s) - 16384 + 1) keeps the LAST 16384 chars,
+    // mirroring the `.slice(-16384)` tail semantics. Bounded fast UPDATE —
+    // safe on the boot path (no file I/O here).
+    db.prepare(`
+      UPDATE error_logs
+         SET log_snippet = substr(log_snippet, length(log_snippet) - 16384 + 1)
+       WHERE log_snippet IS NOT NULL AND length(log_snippet) > 16384
+    `).run();
+    db.prepare('UPDATE schema_version SET version = 11').run();
+    })();
+  }
 }
 
 // ─── Run Mutations ───────────────────────────────────────────────────────────
@@ -906,7 +926,7 @@ export function getRunStats(runId, which) {
  * @param {string}  opts.stage       - 'handshake'|'session'|'speedtest'|'wallet'|'rpc'|'other'
  * @param {string}  [opts.error_code]
  * @param {string}  [opts.error_message]
- * @param {string}  [opts.log_snippet] - up to 512 KB of log context
+ * @param {string}  [opts.log_snippet] - a readable snippet of log context (capped at 16 KB)
  * @returns {number} inserted id
  */
 export function insertErrorLog({
@@ -917,10 +937,14 @@ export function insertErrorLog({
   log_snippet = null,
 }, which) {
   const db = getDb(which);
-  // Persist the full per-node tester log (capped at 512 KB to bound row
-  // size). Pipeline already trims to ~512 KB from the tail; this is the
-  // floor cap so a misbehaving caller can't blow the row.
-  const snippet = log_snippet ? log_snippet.slice(-524288) : null;
+  // Store only a readable snippet of the per-node tester log (capped at 16 KB
+  // = 16384 chars from the tail). The FULL log is persisted to disk in the
+  // per-run audit-*.log file; the DB column exists purely to power the
+  // copy-failure UX, so a bounded tail is all we need. Production callers
+  // already pre-truncate to ~4 KB via pipeline.js (_sanitizeSnippet /
+  // _MAX_SNIPPET); this slice is the backstop so a misbehaving caller can't
+  // blow up the row and bloat audit.db.
+  const snippet = log_snippet ? log_snippet.slice(-16384) : null;
   const info = db.prepare(`
     INSERT INTO error_logs (result_id, stage, error_code, error_message, log_snippet, captured_at)
     VALUES (@result_id, @stage, @error_code, @error_message, @log_snippet, @captured_at)

test/db.smoke.test.js

@@ -8,7 +8,7 @@
 
 import { getDb, useDb, insertRun, updateRunOnFinish, insertResult, insertResultsBatch,
   getRun, findRunByKey, listRuns, getLatestResultPerNode,
-  getNodeHistory, getNetworkStats, closeDb } from '../core/db.js';
+  getNodeHistory, getNetworkStats, insertErrorLog, getNodeErrors, closeDb } from '../core/db.js';
 
 // ─── Use a fresh in-memory DB for this test run ───────────────────────────────
 // `useDb` sets the module singleton so all exported helpers target this handle.
@@ -182,6 +182,31 @@ const parsed = JSON.parse(history2[0].raw_json);
 eq(parsed.address, 'sentnode1aaa111', 'raw_json.address preserved');
 eq(parsed.moniker, 'TestNode Alpha', 'raw_json.moniker preserved');
 
+// 12. schema_version is up to date (latest forward migration applied)
+console.log('12. schema_version...');
+const schemaRow = db.prepare('SELECT MAX(version) AS version FROM schema_version').get();
+eq(schemaRow.version, 11, 'freshly-opened DB reports schema_version 11');
+
+// 13. error_logs.log_snippet is capped at 16 KB (16384 chars)
+console.log('13. error_logs log_snippet cap...');
+// Insert a fresh failed result so we have a result_id, then attach an
+// oversized log snippet. insertErrorLog must clamp it to the 16 KB backstop.
+const capRunId = insertRun({ started_at: NOW - 5_000, mode: 'p2p' });
+const capResultId = Number(insertResult(Number(capRunId), { ...SAMPLE_FAIL, address: 'sentnode1cap999' }));
+insertErrorLog({
+  result_id: capResultId,
+  stage: 'handshake',
+  error_code: 'HANDSHAKE_TIMEOUT',
+  error_message: 'oversized snippet stress',
+  log_snippet: 'x'.repeat(50000),
+});
+const capErrors = getNodeErrors('sentnode1cap999', { limit: 1 });
+assert(capErrors.length >= 1, 'getNodeErrors returns the inserted error log');
+assert(
+  capErrors[0].log_snippet != null && capErrors[0].log_snippet.length <= 16384,
+  `log_snippet capped at <= 16384 chars (got ${capErrors[0].log_snippet?.length})`,
+);
+
 // ─── Results ──────────────────────────────────────────────────────────────────
 
 console.log(`\n${'='.repeat(50)}`);