- About TiDB
- Quick Start
- Software and Hardware Requirements
- Environment Configuration Checklist
- Topology Patterns
- Install and Start
- Verify Cluster Status
- Backup and Restore
- Read Historical Data
- Configure Time Zone
- Daily Checklist
- Maintain TiFlash
- Maintain TiDB Using TiUP
- Modify Configuration Online
- Monitor and Alert
- TiDB Troubleshooting Map
- Identify Slow Queries
- Analyze Slow Queries
- SQL Diagnostics
- Identify Expensive Queries
- Statement Summary Tables
- Troubleshoot Hotspot Issues
- Troubleshoot Increased Read and Write Latency
- Troubleshoot Cluster Setup
- Troubleshoot High Disk I/O Usage
- Troubleshoot Lock Conflicts
- Troubleshoot TiFlash
- Troubleshoot Write Conflicts in Optimistic Transactions
- Performance Tuning
- System Tuning
- Software Tuning
- SQL Tuning
- Understanding the Query Execution Plan
- SQL Optimization Process
- Logic Optimization
- Physical Optimization
- Prepare Execution Plan Cache
- Control Execution Plans
- Multiple Data Centers in One City Deployment
- Three Data Centers in Two Cities Deployment
- Best Practices
- Use Placement Rules
- Use Load Base Split
- Use Store Limit
- TiDB Ecosystem Tools
- Use Cases
- Backup & Restore (BR)
- TiDB Binlog
- TiDB Lightning
- Cluster Architecture
- Key Monitoring Metrics
- SQL Language Structure and Syntax
- SQL Statements
ADMIN CANCEL DDL
ADMIN CHECKSUM TABLE
ADMIN CHECK [TABLE|INDEX]
ADMIN SHOW DDL [JOBS|QUERIES]
CREATE [GLOBAL|SESSION] BINDING
CREATE TABLE LIKE
DROP [GLOBAL|SESSION] BINDING
SET DEFAULT ROLE
SET [NAMES|CHARACTER SET]
SET [GLOBAL|SESSION] <variable>
SHOW ANALYZE STATUS
SHOW [GLOBAL|SESSION] BINDINGS
SHOW CHARACTER SET
SHOW [FULL] COLUMNS FROM
SHOW CREATE SEQUENCE
SHOW CREATE TABLE
SHOW CREATE USER
SHOW DRAINER STATUS
SHOW [FULL] FIELDS FROM
SHOW INDEX [FROM|IN]
SHOW INDEXES [FROM|IN]
SHOW KEYS [FROM|IN]
SHOW MASTER STATUS
SHOW [FULL] PROCESSSLIST
SHOW PUMP STATUS
SHOW TABLE NEXT_ROW_ID
SHOW TABLE REGIONS
SHOW TABLE STATUS
SHOW [FULL] TABLES
SHOW [GLOBAL|SESSION] VARIABLES
- Data Types
- Functions and Operators
- Type Conversion in Expression Evaluation
- Control Flow Functions
- String Functions
- Numeric Functions and Operators
- Date and Time Functions
- Bit Functions and Operators
- Cast Functions and Operators
- Encryption and Compression Functions
- Information Functions
- JSON Functions
- Aggregate (GROUP BY) Functions
- Window Functions
- Miscellaneous Functions
- Precision Math
- Set Operations
- List of Expressions for Pushdown
- Clustered Indexes
- Generated Columns
- SQL Mode
- Garbage Collection (GC)
- Character Set and Collation
- System Tables
- TiDB Dashboard
- Overview Page
- Cluster Info Page
- Key Visualizer Page
- Metrics Relation Graph
- SQL Statements Analysis
- Slow Queries Page
- Cluster Diagnostics
- Search Logs Page
- Profile Instances Page
- TiDB Dashboard
- Command Line Flags
- Configuration File Parameters
- System Variables
- Storage Engines
- Errors Codes
- Table Filter
- Schedule Replicas by Topology Labels
- Release Notes
- All Releases
- TiDB Roadmap
This document describes the monitoring items of TiFlash.
If you use TiUP to deploy the TiDB cluster, the monitoring system (Prometheus & Grafana) is deployed at the same time. For more information, see Overview of the Monitoring Framework.
The Grafana dashboard is divided into a series of sub dashboards which include Overview, PD, TiDB, TiKV, Node_exporter, and so on. A lot of metrics are there to help you diagnose.
TiFlash has three dashboard panels: TiFlash-Summary, TiFlash-Proxy-Summary, and TiFlash-Proxy-Details. The metrics on these panels indicate the current status of TiFlash. The TiFlash-Proxy-Summary and TiFlash-Proxy-Details panels mainly show the information of the Raft layer and the metrics are detailed in Key Monitoring Metrics of TiKV.
It is recommended that you use TiDB v4.0.5 or later versions for improved monitor on TiFlash.
The following sections introduce the default monitoring information of TiFlash-Summary.
- Store size: The storage size used by each TiFlash instance.
- Available size: The storage size available for each TiFlash instance.
- Capacity size: The storage capacity for each TiFlash instance.
- Uptime: The runtime of TiFlash since last restart.
- Memory: The memory usage per TiFlash instance.
- CPU Usage: The CPU utilization per TiFlash instance.
- FSync OPS: The number of fsync operations per TiFlash instance per second.
- File Open OPS: The number of
openoperations per TiFlash instance per second.
- Opened File Count: The number of file descriptors currently opened by each TiFlash instance.
Store size, FSync OPS, File Open OPS, and Opened File Count currently only cover the monitoring information of the TiFlash storage layer and do not cover that in TiFlash-Proxy.
- Request QPS: The number of coprocessor requests received by all TiFlash instances.
batchis the number of batch requests.
batch_copis the number of coprocessor requests in the batch requests.
copis the number of coprocessor requests that are sent directly via the coprocessor interface.
cop_dagis the number of dag requests in all coprocessor requests.
super_batchis the number of requests to enable the Super Batch feature.
- Executor QPS: The number of each type of dag executors in the requests received by all TiFlash instances.
table_scanis the table scan executor.
selectionis the selection executor.
aggregationis the aggregation executor.
limitis the limit executor.
- Request Duration: The total duration of all TiFlash instances processing coprocessor requests. The total duration is from the time that the coprocessor request is received to the time that the response to the request is completed.
- Error QPS: The number of errors of all TiFlash instances processing coprocessor requests.
meet_lockmeans that the read data is locked.
region_not_foundmeans that the Region does not exist.
epoch_not_matchmeans the read Region epoch is inconsistent with the local epoch.
kv_client_errormeans that the communication with TiKV returns an error.
internal_erroris the internal system error of TiFlash.
otheris other types of errors.
- Request Handle Duration: The duration of all TiFlash instances processing coprocessor requests. The processing time is from starting to execute the coprocessor request to completing the execution.
- Response Bytes/Seconds: The total bytes of the response from all TiFlash instances.
- Cop task memory usage: The total memory usage of all TiFlash instances processing coprocessor requests.
- Handling Request Number: The total number of all TiFlash instances processing coprocessor requests. The classification of the requests is the same as that of Request QPS.
- Schema Version: The version of the schema currently cached in each TiFlash instance.
- Schema Apply OPM: The number of TiDB
schema diffsynchronized in
applyoperations by all TiFlash instances per minute. This item includes the count of three types of
full apply, and
diff applyis the normal process of a single apply. If
failed applyincreases by
1, and TiFlash rolls back to
full applyand pulls the latest schema information to update the schema version of TiFlash.
- Schema Internal DDL OPM: The number of specific DDL operations executed per minute in all TiFlash instances.
- Schema Apply Duration: The time used for a single
apply schemaoperation in all TiFlash instances.
- Write Command OPS: The number of write requests received per second by the storage layer of all TiFlash instances.
- Write Amplification: Write amplification of each TiFlash instance (the actual bytes of disk writes divided by the written bytes of logical data).
totalis the write amplification since this start, and
5minis the write amplification in the last 5 minutes.
- Read Tasks OPS: The number of read tasks in the storage layer per second for each TiFlash instance.
- Rough Set Filter Rate: The proportion of the number of packets read by each TiFlash instance in the last minute that are filtered by the rough set index of the storage layer.
- Internal Tasks OPS: The number of times that all TiFlash instances perform internal data sorting tasks per second.
- Internal Tasks Duration: The time consumed by all TiFlash instances for internal data sorting tasks.
- Page GC Tasks OPM: The number of times that all TiFlash instances perform Delta data sorting tasks per minute.
- Page GC Tasks Duration: The distribution of time consumed by all TiFlash instances to perform Delta data sorting tasks.
- Disk Write OPS: The number of disk writes per second by all TiFlash instances.
- Disk Read OPS: The number of disk reads per second by all TiFlash instances.
- Write flow: The traffic of disk writes by all TiFlash instances.
- Read flow: The traffic of disk reads by all TiFlash instances.
These metrics only cover the monitoring information of the TiFlash storage layer and do not cover that in TiFlash-Proxy.
- Read Index OPS: The number of times that each TiFlash instance triggers the
read_indexrequest per second, which equals to the number of Regions triggered.
- Read Index Duration: The time used by
read_indexfor all TiFlash instances. Most time is used for interaction with the Region leader and retry.
- Wait Index Duration: The time used by
wait_indexfor all TiFlash instances, namely the time used to wait until local index >= read_index after the
read_indexrequest is received.