existsPartition

Syntax

existsPartition(path, [tableName])

Arguments

path is a string indicating the path of a partition folder.

tableName is a string indicating the table name. If chunkGranularity is set to “DATABASE” when creating the database, tableName is not required. If chunkGranularity is set to “TABLE”:

• If the parameter path contains the physical index of the table (which can be retrieved with the function listTables), tableName is not required.

• Otherwise, tableName must be specified.

Details

Check if the specified partition exists.

Examples

Check if the specified partition exists. The following scripts must be executed on a data node or compute node.

$ n=1000000
$ ID=rand(10, n)
$ dates=2017.08.07..2017.08.11
$ date=rand(dates, n)
$ x=rand(10.0, n)
$ t=table(ID, date, x)

$ db = database("dfs://valueDB", VALUE, 2017.08.07..2017.08.11)
$ pt = db.createPartitionedTable(t, `pt, `date);
$ pt.append!(t);

$ listTables("dfs://valueDB")

tableName	physicalIndex
pt	s

$ existsPartition("dfs://valueDB/20170807/s");
true

//When the chunk granularity of the database is at TABLE level and the parameter path doesn't contain table physicalIndex, the parameter tableName must be specified or the partition cannot be found.

$ existsPartition("dfs://valueDB/20170807", `pt)
true

$ existsPartition("dfs://valueDB/20170807");
false

$ existsPartition("dfs://valueDB");
false

$ existsPartition("dfs://valueDB/20170807/s/pt");
false