TKCat (version 1.2.3)

write_MergeTree: Write a Clickhouse MergeTree table

Description

Write a Clickhouse MergeTree table

Usage

write_MergeTree(
  con,
  dbName,
  tableName,
  value,
  rtypes = NULL,
  nullable = NULL,
  lowCardinality = NULL,
  sortKey = NULL,
  indexes = NULL,
  projections = NULL,
  by = 10^7
)

Value

No return value, called for side effects

Arguments

con

the clickhouse connection

dbName

the name of the database

tableName

the name of the table

value

the table to import

rtypes

a named character vector giving the R type of each and every columns. If NULL (default), types are guessed from value.

nullable

a character vector indicating the name of the columns which are nullable (default: NULL)

lowCardinality

a character vector indicating the name of the columns with low cardinality (default: NULL)

sortKey

a character vector indicating the name of the columns used in the sort key. If NULL (default), all the non-nullable columns are used in the key.

indexes

a data.frame with 3 columns:

• idx: index name,

• field: field name,

• type: 'bloom_filter(0.01)', 'minmax'... (see https://clickhouse.com/docs/optimize/skipping-indexes)

• granularity: index granularity

projections

a data.frame with 3 columns:

• projection: projection name (e.g., "prj_tn_cn"),

• select: select statement (e.g., "SELECT *"),

• clause: clause for the projection (e.g., "ORDER BY (cn)")

by

the size of the batch: number of records to import together (default: 10^7)