StarRocks BE Memory Architecture and Resource Configuration Overview - E-MapReduce - Alibaba Cloud - E-MapReduce

Memory categories

To add or modify BE-related configurations in the E-MapReduce console, navigate to the Services page of your target cluster, open the Configure page for the STARROCKS service, and select the be.conf tab. For detailed instructions, see Manage configuration items.

Label	Metric name	Description	BE configuration
process	starrocks_be_process_mem_bytes	The actual memory used by the BE process, excluding reserved free memory.	mem_limit
query_pool	starrocks_be_query_mem_bytes	The total memory used by the BE query layer.	None
load	starrocks_be_load_mem_bytes	The total memory used for data loads.	load_process_max_memory_limit_bytes, load_process_max_memory_limit_percent
table_meta	starrocks_be_tablet_meta_mem_bytes	The total memory used for metadata.	None
compaction	starrocks_be_compaction_mem_bytes	The total memory used for compaction.	compaction_max_memory_limit, compaction_max_memory_limit_percent
column_pool	starrocks_be_column_pool_mem_bytes	Memory for the Column Pool, a column cache used to accelerate data reads from the storage layer.	None
page_cache	starrocks_be_storage_page_cache_mem_bytes	The page cache for the BE storage layer.	disable_storage_page_cache, storage_page_cache_limit
chunk_allocator	starrocks_be_chunk_allocator_mem_bytes	A per-CPU-core cache used to accelerate the allocation of small memory chunks.	chunk_reserved_bytes_limit
consistency	starrocks_be_consistency_mem_bytes	The memory used for periodic consistency checks.	consistency_max_memory_limit_percent, consistency_max_memory_limit
schema_change	starrocks_be_schema_change_mem_bytes	The total memory used by schema change tasks.	memory_limitation_per_thread_for_schema_change
clone	starrocks_be_clone_mem_bytes	The total memory used by tablet clone tasks.	None
update	starrocks_be_update_mem_bytes	The total memory used by the primary key model.	None

Memory configurations

BE configurations

Parameter	Default	Description
mem_limit	90%	The memory limit for the BE process. By default, the hard limit is 90% of the host's memory, and the soft limit is 80%. You do not need to configure this parameter if the BE is deployed on a dedicated host. If it is co-located with other memory-intensive services, set this parameter according to your workload and resource plan.
load_process_max_memory_limit_bytes	107374182400	These parameters specify the absolute and percentage-based memory limits for data loads, respectively. The system uses the smaller value between `mem_limit * load_process_max_memory_limit_percent / 100` and `load_process_max_memory_limit_bytes` as the final memory limit. If the memory used for a load reaches this limit, the system triggers disk flush and backpressure mechanisms.
load_process_max_memory_limit_percent	30
compaction_max_memory_limit	-1	These parameters specify the absolute and percentage-based memory limits for compaction, respectively. The system uses the smaller value between `mem_limit * compaction_max_memory_limit_percent / 100` and `compaction_max_memory_limit` as the final memory limit for compaction. The default value -1 indicates no limit. We recommend that you do not change the default value. If the memory used by a compaction task reaches this limit, the task fails.
compaction_max_memory_limit_percent	100
disable_storage_page_cache	true	Specifies whether to disable the page cache for the BE storage layer. This parameter is used with `storage_page_cache_limit`. Enable the page cache to accelerate queries if you have sufficient memory and run large-scale queries.
storage_page_cache_limit	0	The memory limit for the page cache of the BE storage layer.
chunk_reserved_bytes_limit	2147483648	A cache that accelerates the allocation of small memory blocks. The default limit is 2,147,483,648 bytes (2 GB). Consider increasing this value if you have sufficient memory resources.
consistency_max_memory_limit	10G	These parameters specify the absolute and percentage-based memory limits for consistency check tasks. The system uses the smaller value between `mem_limit * consistency_max_memory_limit_percent / 100` and `consistency_max_memory_limit` as the final memory limit. If memory usage exceeds this limit, the task fails.
consistency_max_memory_limit_percent	20
memory_limitation_per_thread_for_schema_change	2	The memory limit for a single schema change task. If memory usage exceeds this limit, the schema change task fails.
tc_use_memory_min	10737418240	The minimum memory that TCMalloc reserves. If the amount of idle memory is less than this value, StarRocks does not release it to the operating system.

Session variables

Parameter

Default

Description

exec_mem_limit

2147483648

The memory limit for a single instance.

load_mem_limit

0

The memory limit for a single load task.

A default value of 0 means this variable is ignored, and exec_mem_limit is used as the memory limit instead.

View memory usage

You can analyze BE memory usage in the following two ways:

Method 1: Analyze via metrics interface

Metrics are updated every 10 seconds. Access the metrics with the following cURL command:

# The default webserver_port for a BE is 8040.
curl -XGET -s http://BE_IP:8040/metrics | grep "^starrocks_be_.*_mem_bytes\|^starrocks_be_tcmalloc_bytes_in_use"

Note

For descriptions of these metrics, see Memory usage categories.

Method 2: Analyze via mem_tracker interface

You can access the interface using a web browser or a cURL command. This example uses a browser.

# The default webserver_port for a BE is 8040.
http://be_ip:8040/mem_tracker

The page displays the Memory Usage Detail table with columns: level, Label, Parent, Limit, Current Consumption, and Peak Consumption. The top-level entry is process, which contains sub-modules including query_pool, load, compaction, schema_change, column_pool, page_cache, chunk_allocator, clone, consistency, tablet_meta, and update. You can view the memory limit, current consumption, and peak consumption of each module.

The output includes the following parameters:

level: MemTracker has a tree structure. The first level represents the total memory used by the BE, and the second level represents the memory usage for each category.
Label: The label for the memory category. For descriptions of the labels, see Memory usage categories.
Parent: The label of the parent node.
Limit: The memory usage limit. A value of none indicates that there is no limit.
Current consumption: The current memory consumption.
Peak consumption: The peak memory consumption.