fix(deserializer): heatmap routing drops all actions for unassigned contracts when ds_pool_size = 1

[igorls]

Problem

With scaling.routing_mode: "heatmap" and scaling.ds_pool_size: 1, the indexer ingests blocks and deltas correctly but get_actions returns 0 and /v2/health reports Elasticsearch "Error" because the {chain}-action-* index is never created. All action traces are silently dropped.

Root cause

In MainDSWorker.routeToPool (src/indexer/workers/deserializer.ts), the heatmap path uses 0-indexed worker ids from dsPoolMap[code][2] and converts them to a 1-indexed ds_pool:N queue with selected_q += 1.

selected_q was initialized to 1. When a contract has no heatmap assignment yet — empty dsPoolMap on a fresh/low-traffic chain, or any contract not seen since the last update_pool_map IPC update — the assignment block is skipped, selected_q stays 1, and += 1 makes it 2. Traces are published to {chain}:ds_pool:2.

But ds_pool workers are created in master.ts setupDSPool() with local_id = i + 1 for i in 0..ds_pool_size-1, consuming queues ds_pool:1..ds_pool_size. With ds_pool_size: 1 only ds_pool:1 exists, so a default-exchange publish to the unrouted ds_pool:2 is a no-op and the traces are lost. Deployments with ds_pool_size >= 2 happen to have a ds_pool:2 consumer, so they never observe this.

The heatmap worker ids in dsPoolMap[code][2] are 0-indexed (master builds them with for (let i = 0; i < pool_size; i++) proposedWorkers.push(i)), and selected_q += 1 is exactly the 0→1-index conversion. The init value should therefore represent 0-indexed worker 0, i.e. the first pool worker.

Fix

Initialize selected_q to 0 instead of 1, so an unassigned contract falls back to the first pool worker (queue ds_pool:1). round_robin reassigns selected_q and default exits, so neither relies on the initial value.

Workarounds (for affected users on older builds)

• Set scaling.routing_mode: "round_robin", or
• Set scaling.ds_pool_size: 2 or higher.

Verification

tsc compiles cleanly with no errors. Reproduced and fixed against a local Antelope Spring 1.2.2 node: before the fix, blocks/deltas indexed but get_actions = 0 and ES health = Error; after, a clean re-index produced the chain's full action history (transfer/create/issue/setup/setfeesmap/setcode/newaccount/…) with all four /v2/health services OK.

Optional follow-up (not in this PR)

A startup warning when routing_mode === "heatmap" && ds_pool_size < 2 would surface the (now-functional but pointless) single-worker-heatmap config explicitly. Happy to add it here or separately if you'd like.

[gemini-code-assist]

Code Review

This pull request updates the deserializer worker to initialize selected_q to 0 instead of 1. This ensures that contracts without a heatmap assignment correctly fall back to the first pool worker (queue ds_pool:1) instead of routing to a non-existent ds_pool:2 queue, which previously caused action traces to be silently dropped when ds_pool_size is 1. There are no review comments, so I have no feedback to provide.