optimise clickhouse config

Author: nicktrn

hosting/k8s/helm/templates/configmap.yaml

@@ -7,25 +7,5 @@ metadata:
     {{- include "trigger-v4.labels" . | nindent 4 }}
 data:
   override.xml: |
-    <clickhouse>
-      <logger>
-        <level>warning</level>
-      </logger>
-      <!-- Memory optimization for resource-constrained environments -->
-      <max_memory_usage>1073741824</max_memory_usage> <!-- 1GB -->
-      <max_memory_usage_for_user>536870912</max_memory_usage_for_user> <!-- 512MB -->
-      <max_memory_usage_for_all_queries>1073741824</max_memory_usage_for_all_queries> <!-- 1GB -->
-      <max_server_memory_usage>1610612736</max_server_memory_usage> <!-- 1.5GB -->
-      <max_concurrent_queries>50</max_concurrent_queries>
-      <max_thread_pool_size>4</max_thread_pool_size>
-      <background_pool_size>2</background_pool_size>
-      <background_merges_mutations_concurrency_ratio>2</background_merges_mutations_concurrency_ratio>
-      <!-- Reduce cache sizes -->
-      <mark_cache_size>536870912</mark_cache_size> <!-- 512MB -->
-      <uncompressed_cache_size>134217728</uncompressed_cache_size> <!-- 128MB -->
-      <compiled_expression_cache_size>134217728</compiled_expression_cache_size> <!-- 128MB -->
-      <!-- Optimize merge settings -->
-      <merge_max_block_size>8192</merge_max_block_size>
-      <max_bytes_to_merge_at_max_space_in_pool>1073741824</max_bytes_to_merge_at_max_space_in_pool> <!-- 1GB -->
-    </clickhouse>
+{{ .Values.clickhouse.config.override | indent 4 }}
 {{- end }}

hosting/k8s/helm/values.yaml

@@ -345,6 +345,25 @@ clickhouse:
     # - name: CUSTOM_VAR
     #   value: "custom-value"
 
+  # ClickHouse configuration override
+  # You can provide your own override.xml content here
+  # These defaults are based on official recommendations for systems with <16GB RAM:
+  # https://clickhouse.com/docs/operations/tips
+  config:
+    override: |
+      <clickhouse>
+        <logger>
+          <level>warning</level>
+        </logger>
+        <!-- Official recommendations for systems with <16GB RAM -->
+        <mark_cache_size>524288000</mark_cache_size> <!-- 500MB -->
+        <max_thread_pool_size>1</max_thread_pool_size>
+        <max_block_size>8192</max_block_size>
+        <max_download_threads>1</max_download_threads>
+        <input_format_parallel_parsing>0</input_format_parallel_parsing>
+        <output_format_parallel_formatting>0</output_format_parallel_formatting>
+      </clickhouse>
+
 # MinIO configuration
 minio:
   enabled: true