Load from Local Files
After you have defined a graph schema, you can create a loading job, specify your data sources, and run the job to load data.
The steps are similar whether you are loading from local files, from cloud storage, or any of the other supported sources. We will call out whether a particular step is common for all loading or specific to a data source or loading mode.
Example Schema
This example uses part of the LDBC_SNB schema:
//Vertex Types:
CREATE VERTEX Person(PRIMARY_ID id UINT, firstName STRING, lastName STRING,
gender STRING, birthday DATETIME, creationDate DATETIME, locationIP STRING,
browserUsed STRING, speaks SET<STRING>, email SET<STRING>)
WITH STATS="OUTDEGREE_BY_EDGETYPE", PRIMARY_ID_AS_ATTRIBUTE="true"
CREATE VERTEX Comment(PRIMARY_ID id UINT, creationDate DATETIME,
locationIP STRING, browserUsed STRING, content STRING, length UINT)
WITH STATS="OUTDEGREE_BY_EDGETYPE", PRIMARY_ID_AS_ATTRIBUTE="true"
//Edge Types:
CREATE DIRECTED EDGE HAS_CREATOR(FROM Comment, TO Person)
WITH REVERSE_EDGE="HAS_CREATOR_REVERSE"
If we were loading from a remote data source, the next step would be to create a DATA_SOURCE object.
A DATA_SOURCE provides a standard interface for all supported data source types, so that loading jobs can be written without regard for the data source.
This is not necessary for local files.
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Create a loading job
A loading job tells the database how to construct vertices and edges from data sources. The loading job body has two parts:
-
DEFINE statements create variables to refer to data sources. These can refer to actual files or be placeholder names. The actual data sources can be given when running the loading job.
-
LOAD statements specify how to take the data fields from files to construct vertices or edges.
Example loading job for local files
The following is an example loading job for local files.
USE GRAPH ldbc_snb
CREATE LOADING JOB load_data FOR GRAPH ldbc_snb {
DEFINE FILENAME file_Person = "/data/person.csv";
DEFINE FILENAME file_Comment = "m3:/data/comment.csv";
DEFINE FILENAME file_Comment_hasCreator_Person=
"ALL:/data/hasCreator.json";
LOAD file_Person TO VERTEX Person
VALUES($1, $2, $3, $4, $5, $0, $6, $7,
SPLIT($8, ";"), SPLIT($9, ";"))
USING SEPARATOR="|", HEADER="true", EOL="\n";
LOAD file_Comment TO VERTEX Comment
VALUES($1, $0, $2, $3, $4, $5)
USING SEPARATOR="|", HEADER="true", EOL="\n";
LOAD file_Comment_hasCreator_Person TO EDGE HAS_CREATOR
VALUES($1 Comment, $2 Person)
USING JSON_FILE="true";
}
Define filenames
First we define filenames, which are local variables referring to data files (or data objects).
The terms FILENAME and filevar are used for legacy reasons, but a filevar can also be an object in a data object store.
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DEFINE FILENAME filevar ["=" file_descriptor ];
The file descriptor can be specified at compile-time or at runtime. Runtime settings override compile-time settings:
RUN LOADING JOB job_name USING filevar=file_descriptor_override
Local file descriptors
For local file loading, the file_desciptor
is a file path or folder path string, enclosed in quotation marks. Here are examples of the syntax for various cases:
-
An absolute or relative path for either a file or a folder on the machine where the job is run:
"/data/graph.csv"
-
An absolute or relative path for either a file or a folder on all machines in the cluster:
"ALL:/data/graph.csv"
-
An absolute or relative path for either a file or a folder on any machine in the cluster:
"ANY:/data/graph.csv"
-
A list of machine-specific paths:
"m1:/data1.csv, m2|m3|m5:/data/data2.csv"
Specify the data mapping
Next, we use LOAD statements to describe how the incoming data will be loaded to attributes of vertices and edges. Each LOAD statement handles the data mapping, and optional data transformation and filtering, from one filename to one or more vertex and edge types.
LOAD [ source_object|filevar|TEMP_TABLE table_name ]
destination_clause [, destination_clause ]*
[ TAGS clause ] (1)
[ USING clause ];
1 | As of v3.9.3, TAGS are deprecated. |
Let’s break down one of the LOAD statements in our example:
LOAD file_Person TO VERTEX Person
VALUES($1, $2, $3, $4, $5, $0, $6, $7,
SPLIT($8, ";"), SPLIT($9, ";"))
USING SEPARATOR="|", HEADER="true", EOL="\n";
-
$0
,$1
,… refer to the first, second, … columns in each line a data file. -
SEPARATOR="|"
says the column separator character is the pipe (|
). The default is comma (,
). -
HEADER="true"
says that the first line in the source contains column header names instead of data. These names can be used instead of the columnn numbers. -
SPLIT
is one of GSQL’s ETL functions. It says that there is a multi-valued column, which has a separator character to mark the subfields in that column.
Refer to Creating a Loading Job in the GSQL Language Reference for descriptions of all the options for loading jobs.
Run the loading job
Use the command RUN LOADING JOB
to run the loading job.
RUN LOADING JOB [-noprint] job_name [
USING filevar [="file_descriptor"][, filevar [="file_descriptor"]]*
[,EOF="eof_mode"]
]
-noprint
By default, the loading job will run in the foreground and print the loading status and statistics after you submit the job.
If the -noprint
option is specified, the job will run in the background after displaying the job ID and the location of the log file.
filevar list
The optional USING
clause may contain a list of file variables. Each file variable may optionally be assigned a file_descriptor
, obeying the same format as in CREATE LOADING JOB
. This list of file variables determines which parts of a loading job are run and what data files are used.
When a loading job is compiled, it generates one RESTPP endpoint for each filevar
and source_object. As a consequence, a loading job can be run in parts. When RUN LOADING JOB
is executed, only those endpoints whose filevar or file identifier (GSQL_FILENAME_n
) is mentioned in the USING
clause will be used. However, if the USING
clause is omitted, then the entire loading job will be run.
If a file_descriptor
is given, it overrides the file_descriptor
defined in the loading job. If a particular filevar
is not assigned a file_descriptor
either in the loading job or in the RUN LOADING JOB
statement, an error is reported and the job exits.
Streaming mode is not available for local file loading, so the EOF parameter will be ignored. |
Manage and monitor your loading job
When a loading job starts, the GSQL server assigns it a job ID and displays it for the user to see. There are four key commands to monitor and manage loading jobs:
SHOW LOADING STATUS job_id|ALL
ABORT LOADING JOB job_id|ALL
RESUME LOADING JOB job_id
SHOW LOADING ERROR job_id
SHOW LOADING STATUS
shows the current status of either a specified loading job or all current jobs, this command should be within the scope of a graph:
GSQL > USE GRAPH graph_name
GSQL > SHOW LOADING STATUS ALL
For each loading job, the above command reports the following information:
-
Loading status
-
Loaded lines/Loaded objects/Error lines
-
Average loading speed
-
Size of loaded data
-
Duration
When inspecting all current jobs with SHOW LOADING STATUS ALL
, the jobs in the FINISHED
state will be omitted as they are considered to have successfully finished.
You can use SHOW LOADING STATUS job_id
to check the historical information of finished jobs.
If the report for this job contains error data, you can use SHOW LOADING ERROR job_id
to see the original data that caused the error.
See Managing and Inspecting a Loading Job for more details.
Manage loading job concurrency
See Loading Job Concurrency for how to manage the concurrency of loading jobs.