Prioritize growth retries and randomize intake

src/services/account-growth.ts

@@ -196,6 +196,9 @@ export class AccountGrowthService {
 
     let claimed = this.repository.claimNext(this.accountId, this.workerId, LEASE_MS, now);
     if (!claimed) {
+      if (this.repository.hasPendingQueueWork(this.accountId)) {
+        return { kind: 'idle', reason: 'Existing growth queue is waiting for its retry time' };
+      }
       const discovery = await this.discover(signal);
       if (discovery.kind === 'idle') return discovery;
       claimed = this.repository.claimNext(this.accountId, this.workerId, LEASE_MS, this.now());
@@ -241,7 +244,10 @@ export class AccountGrowthService {
       else rejections.set(screening.reason, (rejections.get(screening.reason) ?? 0) + 1);
     }
 
-    const intake = this.repository.enqueueDiscovered(this.accountId, eligible, now, 10);
+    // Queue one thread at a time. Subreddit selection is randomized on every
+    // new unit of work, rather than one random community producing a long,
+    // predictable run of comments from a ten-thread batch.
+    const intake = this.repository.enqueueDiscovered(this.accountId, eligible, now, 1);
     this.logger.info(
       `Growth intake r/${subreddit.subreddit} for u/${this.options.redditUsername}: `
       + `${posts.length} fetched; ${eligible.length} eligible; ${intake.discovered} queued; `