Parameter Configuration and Monitoring Metrics

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Última atualização: 2026-09-01 14:34:02

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This document describes the parameter configuration and monitoring metrics of Column Store Index (CSI).
Prerequisites
The kernel version of TDSQL-C for MySQL 8.0 is 3.1.20.001 or later.
Note:
For read-only instances that meet the version requirements, the CSI feature can be enabled only on those with four or more CPU cores.
Parameter List
Name
Type
Default Value
Value Range
Description
columnstore_enable
boolean
OFF
OFF / ON
Whether to enable columnstore.
ON: Enable.
OFF: Disable.
columnstore_enable_query_execution
boolean
OFF
OFF / ON
Whether to enable columnar computation.
ON: Enable.
OFF: Disable.
columnstore_enable_proxy_forward
boolean
OFF
OFF / ON
The database proxy automatically routes large queries to column-format storage nodes when the service is connected to the database proxy.
ON: Enable.
OFF: Disable.
columnstore_cost_threshold
numeric
100000
0 - 1.7976931348623157e308
Threshold for large queries.
columnstore_prm_memory_pool_size
integer
1GB
1MB - 100GB
Cache for row-column conversion (memory).
columnstore_buffer_pool_size
integer
1GB
1MB - 16EB
Columnar data cache (memory).
columnstore_ap_buffer_limit
integer
10GB
1GB - ≈16EB
Cache for columnar computation (memory).
columnstore_local_disk_usage_limit
integer
1TB
1MB - 1PB
Columnar data cache (disk).
columnstore_ap_max_temp_directory_size
integer
0
0 - ≈16EB
Columnar computation cache (disk).
Note:
Currently, columnar computing supports only columnar storage and does not yet support reading data directly from row storage.
Parameter Settings for Row/Column Routing
Database proxy mode (queries are forwarded to column-format storage read-only nodes through the database proxy): After you enable the database proxy, load balancing and cross-node row-column traffic distribution are supported in database proxy mode, and column-format storage nodes are registered as column-format storage read-only nodes in the database proxy.
Direct connection mode (direct connection to column-format storage read-only nodes): When directly connecting to a column-format storage node, row-column traffic distribution occurs within the node, but the column-format storage node requires sufficient row storage and column-format storage resources to be planned. Direct connection mode does not support failover.
Parameter
Pure Row Storage
RW
Row Storage RO
Column-Format Storage RO
Description
columnstore_enable
OFF
ON
OFF
ON
Allows column-format storage to manage data (RW maintains metadata only).
columnstore_enable_query_execution
OFF
OFF
OFF
ON
Allows column-format storage to execute SQL.
columnstore_enable_proxy_forward
OFF
ON
ON
ON
The node participates in database proxy traffic routing.
Node Resource Parameter Settings
Global resource parameters are automatically ignored on RW nodes. On RO nodes, they are controlled by the column-format storage and computing switch, and no resource overhead is incurred when the switch is disabled. For configuration reference, see the following:
# Global parameters (ignored on RW)
columnstore_buffer_pool_size = <MEM*0.3>
columnstore_ap_buffer_limit = <MEM*0.1>
columnstore_prm_memory_pool_size = <MEM*0.02>
columnstore_local_disk_usage_limit = <MEM*3>
columnstore_ap_max_temp_directory_size = <MEM>
Default Configuration for Row Store Nodes
On row storage nodes, column-format storage and computing are disabled. Large queries are not recognized, and the nodes do not participate in forwarding. For configuration reference, see the following:
# Pure row storage mode
columnstore_enable = OFF
columnstore_enable_query_execution = OFF
columnstore_enable_proxy_forward = OFF
﻿
# Row storage resource parameters
innodb_buffer_pool_size = <MEM*0.75>
RW Node Configuration (Enabling Column-format Storage and Participating in Row/Column Routing)
RW nodes enable column-format storage but only maintain metadata and do not store column-format data. RW nodes participate in row-column traffic distribution, identifying and forwarding large queries to column-format storage nodes for execution. For configuration reference, see the following:
# Column-format storage RW parameters
columnstore_enable = ON
columnstore_enable_query_execution = OFF
columnstore_enable_proxy_forward = ON
﻿
# Row storage resource parameters
innodb_buffer_pool_size = <MEM*0.75>
﻿
# Global parameters (ignored on RW)
columnstore_buffer_pool_size = <MEM*0.3>
columnstore_ap_buffer_limit = <MEM*0.1>
columnstore_prm_memory_pool_size = <MEM*0.02>
columnstore_local_disk_usage_limit = <MEM*3>
columnstore_ap_max_temp_directory_size = <MEM>
Row Store RO (Participating in Row/Column Routing)
Row storage RO nodes do not allocate resources for column-format storage and execution, but they participate in row-column traffic distribution, identifying and forwarding large queries to column-format storage nodes for execution. For configuration reference, see the following:
# Row storage RO nodes participate in row-column traffic distribution
columnstore_enable = OFF
columnstore_enable_query_execution = OFF
columnstore_enable_proxy_forward = ON
﻿
# Row storage resource parameters
innodb_buffer_pool_size = <MEM*0.75>
Routing Configuration for Column Store RO Nodes (Columnar SQL Execution)
Column-format storage RO nodes allocate resources to storage and computing, and receive large queries that are forwarded or directly connected. The cache must be configured proportionally based on node specifications.
Note:
On row storage nodes, the default innodb buffer pool is 75% of the node memory. On column-format storage nodes, this 75% should be shared by column-format storage and row storage.
# Column-format storage RO parameters
columnstore_enable = ON
columnstore_enable_query_execution = ON
columnstore_enable_proxy_forward = ON
﻿
# Row storage resource adjustment requires allocating a portion to column-format storage.
innodb_buffer_pool_size = <MEM*0.3>
﻿
# Global parameters (effective on column-format storage RO nodes)
columnstore_buffer_pool_size = <MEM*0.3>
columnstore_ap_buffer_limit = <MEM*0.1>
columnstore_prm_memory_pool_size = <MEM*0.02>
columnstore_local_disk_usage_limit = <MEM*3>
columnstore_ap_max_temp_directory_size = <MEM>
CSI Monitoring Metrics
Metric Name
Unit
Aggregation Method
Description
Innodb_csi_select_pushdown
Piece
SUM
Number of executed statements for CSI-based queries.
Innodb_csi_select_fallback
Piece
SUM
Number of CSI rollback statements.
innodb_csi_lag_seconds
Second
MAX
Synchronization delay between read-write instances and instances with CSI enabled.
Innodb_csi_disk_usage
GB
MAX
Storage space used by column store indexes.
txsql_csi_fail
Piece
SUM
Number of column store indexes failed to be created.

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Name	Type	Default Value	Value Range	Description
columnstore_enable	boolean	OFF	OFF / ON	Whether to enable columnstore. ON: Enable. OFF: Disable.
columnstore_enable_query_execution	boolean	OFF	OFF / ON	Whether to enable columnar computation. ON: Enable. OFF: Disable.
columnstore_enable_proxy_forward	boolean	OFF	OFF / ON	The database proxy automatically routes large queries to column-format storage nodes when the service is connected to the database proxy. ON: Enable. OFF: Disable.
columnstore_cost_threshold	numeric	100000	0 - 1.7976931348623157e308	Threshold for large queries.
columnstore_prm_memory_pool_size	integer	1GB	1MB - 100GB	Cache for row-column conversion (memory).
columnstore_buffer_pool_size	integer	1GB	1MB - 16EB	Columnar data cache (memory).
columnstore_ap_buffer_limit	integer	10GB	1GB - ≈16EB	Cache for columnar computation (memory).
columnstore_local_disk_usage_limit	integer	1TB	1MB - 1PB	Columnar data cache (disk).
columnstore_ap_max_temp_directory_size	integer	0	0 - ≈16EB	Columnar computation cache (disk).

Parameter	Pure Row Storage	RW	Row Storage RO	Column-Format Storage RO	Description
columnstore_enable	OFF	ON	OFF	ON	Allows column-format storage to manage data (RW maintains metadata only).
columnstore_enable_query_execution	OFF	OFF	OFF	ON	Allows column-format storage to execute SQL.
columnstore_enable_proxy_forward	OFF	ON	ON	ON	The node participates in database proxy traffic routing.

Metric Name	Unit	Aggregation Method	Description
Innodb_csi_select_pushdown	Piece	SUM	Number of executed statements for CSI-based queries.
Innodb_csi_select_fallback	Piece	SUM	Number of CSI rollback statements.
innodb_csi_lag_seconds	Second	MAX	Synchronization delay between read-write instances and instances with CSI enabled.
Innodb_csi_disk_usage	GB	MAX	Storage space used by column store indexes.
txsql_csi_fail	Piece	SUM	Number of column store indexes failed to be created.

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TDSQL-C for MySQL

Parameter Configuration and Monitoring Metrics

Prerequisites

Parameter List

Parameter Settings for Row/Column Routing

Node Resource Parameter Settings

Default Configuration for Row Store Nodes

RW Node Configuration (Enabling Column-format Storage and Participating in Row/Column Routing)

Row Store RO (Participating in Row/Column Routing)

Routing Configuration for Column Store RO Nodes (Columnar SQL Execution)

CSI Monitoring Metrics

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