Document separated thread pools in the remaining pages

documentation/architecture/query-engine.md

@@ -59,8 +59,13 @@ to process data in table page frames for better CPU use.
   multi-core fashion. Some queries, for example those involving an index, are executed on a single
   thread. Other queries, like those involving `GROUP BY` and `SAMPLE BY`, execute a pipeline with some  single-threaded stages and some multi-threaded stages to avoid slow downs when groups are unbalanced.
 
-- **Worker pools:** QuestDB allows to configure different pools for specialized functions, like
-parsing incoming data, applying WAL file changes, handling PostgreSQL-Wire protocol, or responding to HTTP connections. By default, most tasks are handled by a shared worker pool.
+- **Worker pools:** QuestDB splits work across three thread pools that are sized
+independently: a network pool for HTTP, PostgreSQL and ILP server I/O, a query pool
+for parallel query execution, and a write pool for WAL apply jobs, table writes and
+materialized view refresh. Because query execution has its own pool, a burst of
+ingestion does not starve readers of CPU. Individual subsystems can still be given
+dedicated threads on top of this. See
+[shared workers](/docs/configuration/shared-workers/) for sizing.
 
 - **Query plan caching:**
   The system caches query plans for reuse within the same connection. (Query results are not

documentation/deployment/hetzner.md

@@ -337,7 +337,8 @@ questdb01$ docker restart questdb
 For comprehensive configuration options, see the [Configuration reference](/docs/configuration/overview/) documentation. Common production settings include:
 
 - **Connection limits**: `pg.connection.pool.size`
-- **Memory settings**: `shared.worker.count`
+- **Worker threads**: `shared.network.worker.count`, `shared.query.worker.count`,
+  `shared.write.worker.count`
 - **Security**: [TLS configuration](/docs/security/tls/)
 - **Authentication**: [RBAC setup](/docs/security/rbac/)
 

documentation/getting-started/capacity-planning.md

@@ -188,12 +188,36 @@ for other database processes to use.
 
 ### CPU cores
 
-By default, QuestDB tries to use all available CPU cores.
+By default, QuestDB tries to use all available CPU cores. Assuming that the disk
+is not bottlenecked on IOPS, the throughput of read-only queries scales
+proportionally with the number of available cores, so a machine with more cores
+will provide better query performance.
+
+Work is divided across three independently sized thread pools, which is what you
+tune when one class of work needs more CPU than another:
+
+| Pool | Handles | Setting |
+| ---- | ------- | ------- |
+| Network | HTTP, PostgreSQL and ILP server I/O | `shared.network.worker.count` |
+| Query | Parallel query execution — filters, `GROUP BY` | `shared.query.worker.count` |
+| Write | WAL apply, table writes, materialized view refresh, housekeeping | `shared.write.worker.count` |
+
+Each pool defaults to roughly the CPU count, so the pools oversubscribe the
+machine by design and the OS scheduler arbitrates between them. That is a
+reasonable starting point. Move capacity deliberately when a workload is
+lopsided:
+
+- **Read-heavy** — raise `shared.query.worker.count` and lower
+  `shared.network.worker.count`, provided connection counts are modest.
+- **Ingestion-heavy** — raise `shared.write.worker.count` so WAL apply keeps up
+  with incoming data. A growing WAL apply backlog is the signal to watch.
+- **Many concurrent clients** — raise `shared.network.worker.count`, since I/O
+  rather than query execution is the constraint.
+
+On small machines, cutting a pool too far can leave a subsystem unable to make
+progress; keep at least two threads in each.
 [The guide on shared worker configuration](/docs/configuration/shared-workers/)
-explains how to change the default settings. Assuming that the disk is not
-bottlenecked on IOPS, the throughput of read-only queries scales proportionally
-with the number of available cores. As a result, a machine with more cores will
-provide better query performance.
+covers the defaults and the per-pool affinity settings.
 
 ### Writer page size