TiDB Lightning Configuration

This document provides samples for global configuration, task configuration, and TiKV Importer configuration in TiDB Lightning, and describes the usage of command-line parameters.

Configuration files

TiDB Lightning has two configuration classes: "global" and "task", and they have compatible structures. Their distinction arises only when the server mode is enabled. When server mode is disabled (the default), TiDB Lightning will only execute one task, and the same configuration file is used for both global and task configurations.

TiDB Lightning (Global)

### tidb-lightning global configuration

[lightning]
# The HTTP port for displaying the web interface, pulling Prometheus metrics, exposing debug data, and submitting import tasks (in server mode). Setting it to 0 disables the port.
status-addr = ':8289'

# Server mode. Defaults to false, which means an import task starts immediately after you execute the command.
# If this value is set to true, after you execute the command, TiDB Lightning waits until you submit an import task in the web interface.
# See the "TiDB Lightning Web Interface" section for details.
server-mode = false

# Logging
level = "info"
file = "tidb-lightning.log"
max-size = 128 # MB
max-days = 28
max-backups = 14

TiDB Lightning (Task)

### tidb-lightning task configuration

[lightning]
# Checks whether the cluster satisfies the minimum requirement before starting.
#check-requirements = true

# The maximum number of engines to be opened concurrently.
# Each table is split into one "index engine" to store indices, and multiple
# "data engines" to store row data. These settings control the maximum
# concurrent number for each type of engines.
# These values affect the memory and disk usage of tikv-importer.
# The sum of these two values must not exceed the max-open-engines setting
# for tikv-importer.
index-concurrency = 2
table-concurrency = 6

# The concurrency number of data. It is set to the number of logical CPU
# cores by default. When deploying together with other components, you can
# set it to 75% of the size of logical CPU cores to limit the CPU usage.
#region-concurrency =

# The maximum I/O concurrency. Excessive I/O concurrency causes an increase in
# I/O latency because the disk's internal buffer is frequently refreshed,
# which causes the cache miss and slows down the read speed. Depending on the storage
# medium, this value might need to be adjusted for optimal performance.
io-concurrency = 5

[security]
# Specifies certificates and keys for TLS connections within the cluster.
# Public certificate of the CA. Leave empty to disable TLS.
# ca-path = "/path/to/ca.pem"
# Public certificate of this service.
# cert-path = "/path/to/lightning.pem"
# Private key of this service.
# key-path = "/path/to/lightning.key"

[checkpoint]
# Whether to enable checkpoints.
# While importing data, TiDB Lightning records which tables have been imported, so
# even if TiDB Lightning or another component crashes, you can start from a known
# good state instead of redoing everything.
enable = true
# The schema name (database name) to store the checkpoints.
schema = "tidb_lightning_checkpoint"
# Where to store the checkpoints.
#  - file:  store as a local file.
#  - mysql: store into a remote MySQL-compatible database
driver = "file"
# The data source name (DSN) indicating the location of the checkpoint storage.
# For the "file" driver, the DSN is a path. If the path is not specified, TiDB Lightning would
# default to "/tmp/CHECKPOINT_SCHEMA.pb".
# For the "mysql" driver, the DSN is a URL in the form of "USER:PASS@tcp(HOST:PORT)/".
# If the URL is not specified, the TiDB server from the [tidb] section is used to
# store the checkpoints. You should specify a different MySQL-compatible
# database server to reduce the load of the target TiDB cluster.
#dsn = "/tmp/tidb_lightning_checkpoint.pb"
# Whether to keep the checkpoints after all data are imported. If false, the
# checkpoints will be deleted. Keeping the checkpoints can aid debugging but
# will leak metadata about the data source.
#keep-after-success = false

[tikv-importer]
# Delivery backend, can be "importer", "local", or "tidb".
# backend = "importer"
# The listening address of tikv-importer when backend is "importer". Change it to the actual address.
addr = "172.16.31.10:8287"
# Action to do when trying to insert a duplicated entry in the "tidb" backend.
#  - replace: new entry replaces existing entry
#  - ignore:  keep existing entry, ignore new entry
#  - error:   report error and quit the program
# on-duplicate = "replace"
# The size limit of generated SST files in the "local" backend. It is better
# to be the same as the Region size of TiKV (96 MB by default).
# region-split-size = 100_663_296
# The number of KV pairs sent in one request in the "local" backend.
# send-kv-pairs = 32768
# The directory of local KV sorting in the "local" backend. If the disk
# performance is low (such as in HDD), it is recommended to set the directory
# on a different disk from `data-source-dir` to improve import speed.
# sorted-kv-dir = ""
# The concurrency that TiKV writes KV data in the "local" backend.
# When the network transmission speed between TiDB Lightning and TiKV
# exceeds 10 Gigabit, you can increase this value accordingly.
# range-concurrency = 16

[mydumper]
# Block size for file reading. Keep it longer than the longest string of the data source.
read-block-size = "64KiB" # default value

# Minimum size (in terms of source data file) of each batch of import.
# TiDB Lightning splits a large table into multiple data engine files according to this size.
# batch-size = 107_374_182_400 # Byte (default = 100 GB)

# The engine file needs to be imported sequentially. Due to parallel processing,
# multiple data engines will be imported at nearly the same time, and this
# creates a queue and wastes resources. Therefore, TiDB Lightning slightly
# increases the size of the first few batches to properly distribute
# resources. The scale up factor is controlled by this parameter, which
# expresses the ratio of duration between the "import" and "write" steps
# with full concurrency. This can be calculated by using the ratio
# (import duration/write duration) of a single table of size around 1 GiB.
# The exact timing can be found in the log. If "import" is faster, the batch
# size variance is smaller, and a ratio of zero means a uniform batch size.
# This value should be in the range (0 <= batch-import-ratio < 1).
batch-import-ratio = 0.75

# Local source data directory or the URL of the external storage.
data-source-dir = "/data/my_database"
# If no-schema is set to true, tidb-lightning assumes that the table skeletons
# already exist on the target TiDB cluster, and will not execute the `CREATE
# TABLE` statements.
no-schema = false
# The character set of the schema files, containing CREATE TABLE statements;
# only supports one of:
#  - utf8mb4: the schema files must be encoded as UTF-8; otherwise, an error is reported.
#  - gb18030: the schema files must be encoded as GB-18030; otherwise,
#             an error is reported
#  - auto:    (default) automatically detects whether the schema is UTF-8 or
#             GB-18030. An error is reported if the encoding is neither.
#  - binary:  do not try to decode the schema files
# Note that the *data* files are always parsed as binary regardless of
# schema encoding.
character-set = "auto"

# Assumes the input data are "strict" to speed up processing.
# Implications of strict-format = true are:
#  * in CSV, every value cannot contain literal new lines (U+000A and U+000D, or \r and \n) even
#    when quoted, which means new lines are strictly used to separate rows.
# Strict format allows TiDB Lightning to quickly locate split positions of a large file for parallel
# processing. However, if the input data is not strict, it may split a valid data in half and
# corrupt the result.
# The default value is false for safety over speed.
strict-format = false

# If strict-format is true, TiDB Lightning will split large CSV files into multiple chunks to process in
# parallel. max-region-size is the maximum size of each chunk after splitting.
# max-region-size = "256MiB" # default value

# Only import tables if these wildcard rules are matched. See the corresponding section for details.
filter = ['*.*', '!mysql.*', '!sys.*', '!INFORMATION_SCHEMA.*', '!PERFORMANCE_SCHEMA.*', '!METRICS_SCHEMA.*', '!INSPECTION_SCHEMA.*']

# Configures how CSV files are parsed.
[mydumper.csv]
# Separator between fields. Must not be empty.
separator = ','
# Quoting delimiter. Empty value means no quoting.
delimiter = '"'
# Whether the CSV files contain a header.
# If `header` is true, the first line will be skipped.
header = true
# Whether the CSV contains any NULL value.
# If `not-null` is true, all columns from CSV cannot be NULL.
not-null = false
# When `not-null` is false (that is, CSV can contain NULL),
# fields equal to this value will be treated as NULL.
null = '\N'
# Whether to interpret backslash escapes inside fields.
backslash-escape = true
# If a line ends with a separator, remove it.
trim-last-separator = false

[tidb]
# Configuration of any TiDB server from the cluster.
host = "172.16.31.1"
port = 4000
user = "root"
password = ""
# Table schema information is fetched from TiDB via this status-port.
status-port = 10080
# Address of any PD server from the cluster.
pd-addr = "172.16.31.4:2379"
# tidb-lightning imports TiDB as a library and generates some logs itself.
# This setting controls the log level of the TiDB library.
log-level = "error"

# Sets the TiDB session variable to speed up the Checksum and Analyze operations.
# See https://pingcap.com/docs/dev/reference/performance/statistics/#control-analyze-concurrency
# for the meaning of each setting
build-stats-concurrency = 20
distsql-scan-concurrency = 100
index-serial-scan-concurrency = 20
checksum-table-concurrency = 16

# The default SQL mode used to parse and execute the SQL statements.
sql-mode = "ONLY_FULL_GROUP_BY,NO_ENGINE_SUBSTITUTION"
# Sets maximum packet size allowed for SQL connections.
# Set this to 0 to automatically fetch the `max_allowed_packet` variable from server on every connection.
max-allowed-packet = 67_108_864

# Whether to use TLS for SQL connections. Valid values are:
#  * ""            - force TLS (same as "cluster") if [tidb.security] section is populated, otherwise same as "false"
#  * "false"       - disable TLS
#  * "cluster"     - force TLS and verify the server's certificate with the CA specified in the [tidb.security] section
#  * "skip-verify" - force TLS but do not verify the server's certificate (insecure!)
#  * "preferred"   - same as "skip-verify", but if the server does not support TLS, fallback to unencrypted connection
# tls = ""

# Specifies certificates and keys for TLS-enabled MySQL connections.
# Defaults to a copy of the [security] section.
# [tidb.security]
# Public certificate of the CA. Set to empty string to disable TLS for SQL.
# ca-path = "/path/to/ca.pem"
# Public certificate of this service. Default to copy of `security.cert-path`
# cert-path = "/path/to/lightning.pem"
# Private key of this service. Default to copy of `security.key-path`
# key-path = "/path/to/lightning.key"

# In the local backend and importer backend, when data importing is complete, TiDB Lightning can
# automatically perform the Checksum and Analyze operations. It is recommended
# to leave these as true in the production environment.
# The execution order: Checksum -> Analyze.
# Note that for tidb backend, Checksum and Analyze are not needed, and they are always
# skipped in the actual operation.
[post-restore]
# Specifies whether to perform `ADMIN CHECKSUM TABLE <table>` for each table to verify data integrity after importing.
# The following options are available:
# - "required" (default value): Perform admin checksum. If checksum fails, TiDB Lightning will exit with failure.
# - "optional": Perform admin checksum. If checksum fails, TiDB Lightning will report a WARN log but ignore any error.
# - "off": Do not perform checksum.
# Note that since v4.0.8, the default value has changed from "true" to "required".
# Note:
# 1. Checksum failure usually means import exception (data loss or inconsistency). It is recommended to always enable checksum.
# 2. For backward compatibility, bool values "true" and "false" are also allowed for this field.
# "true" is equivalent to "required" and "false" is equivalent to "off".
checksum = "required"
# Specifies whether to perform `ANALYZE TABLE <table>` for each table after checksum is done.
# Options available for this field are the same as `post-restore`. However, the default value for this field is "optional".
analyze = "optional"

# Configures the background periodic actions.
# Supported units: h (hour), m (minute), s (second).
[cron]
# Duration between which TiDB Lightning automatically refreshes the import mode
# status. Should be shorter than the corresponding TiKV setting.
switch-mode = "5m"
# Duration between which an import progress is printed to the log.
log-progress = "5m"

TiKV Importer

# TiKV Importer configuration file template.

# Log file.
log-file = "tikv-importer.log"
# Log level: trace, debug, info, warn, error, off.
log-level = "info"

# Listening address of the status server. Prometheus can scrape metrics from this address.
status-server-address = "0.0.0.0:8286"

[server]
# The listening address of tikv-importer. tidb-lightning needs to connect to
# this address to write data.
addr = "0.0.0.0:8287"
# Size of the thread pool for the gRPC server.
grpc-concurrency = 16

[metric]
# These settings are relevant when using Prometheus Pushgateway. Normally you should let Prometheus
# to scrape metrics from the status-server-address.
# The Prometheus client push job name.
job = "tikv-importer"
# The Prometheus client push interval.
interval = "15s"
# The Prometheus Pushgateway address.
address = ""

[rocksdb]
# The maximum number of concurrent background jobs.
max-background-jobs = 32

[rocksdb.defaultcf]
# Amount of data to build up in memory before flushing data to the disk.
write-buffer-size = "1GB"
# The maximum number of write buffers that are built up in memory.
max-write-buffer-number = 8

# The compression algorithms used in different levels.
# The algorithm at level-0 is used to compress KV data.
# The algorithm at level-6 is used to compress SST files.
# The algorithms at level-1 to level-5 are unused for now.
compression-per-level = ["lz4", "no", "no", "no", "no", "no", "lz4"]

[rocksdb.writecf]
# (same as above)
compression-per-level = ["lz4", "no", "no", "no", "no", "no", "lz4"]

[security]
# The path for TLS certificates. Empty string means disabling secure connections.
# ca-path = ""
# cert-path = ""
# key-path = ""

[import]
# The directory to store engine files.
import-dir = "/mnt/ssd/data.import/"
# Number of threads to handle RPC requests.
num-threads = 16
# Number of concurrent import jobs.
num-import-jobs = 24
# Maximum duration to prepare Regions.
#max-prepare-duration = "5m"
# Split Regions into this size according to the importing data.
#region-split-size = "512MB"
# Stream channel window size. The stream will be blocked on channel full.
#stream-channel-window = 128
# Maximum number of open engines.
max-open-engines = 8
# Maximum upload speed (bytes per second) from Importer to TiKV.
# upload-speed-limit = "512MB"
# Minimum ratio of available space on the target store: `store_available_space`/`store_capacity`.
# Importer pauses uploading SST if the availability ratio of the target store is less than this
# value, to allow enough time for PD to balance Regions.
min-available-ratio = 0.05

Command line parameters

Usage of tidb-lightning

If a command line parameter and the corresponding setting in the configuration file are both provided, the command line parameter will be used. For example, running ./tidb-lightning -L debug --config cfg.toml would always set the log level to "debug" regardless of the content of cfg.toml.

Usage of tidb-lightning-ctl

This tool can execute various actions given one of the following parameters:

The tablename must either be a qualified table name in the form `db`.`tbl` (including the backquotes), or the keyword "all".

Additionally, all parameters of tidb-lightning described in the section above are valid in tidb-lightning-ctl.

Usage of tikv-importer