This guide covers various ways of loading data into the system. We recommend trying option 1, and if that is not sufficient, trying option 2 then option 3.
- Option 1: Loading from a file
- Option 2: Loading from S3 or HDFS using MemSQL Loader
- Option 3: Loading from MySQL
Option 1: Loading Data stored in a file
MemSQL supports standard SQL loading constructs. For instance, after creating tbl_name, run:
LOAD DATA INFILE 'file_name.tsv' INTO TABLE tbl_name
FIELDS TERMINATED BY '\t'
LINES TERMINATED BY '\n'
For more details see LOAD DATA.
Option 2: Importing data from S3 or HDFS
If your data lives in S3 or HDFS, you can use the Data Import functionality in MemSQL Ops to download and ingest files.
Option 3: Loading from MySQL
The popular open source tool mysqldump is a straightforward way to load data from MySQL into MemSQL For example, on a machine with a MySQL database foo, issue the following commands.
mysqldump -h 127.0.0.1 -u root --databases foo > foodump.sql
You can also dump specific tables by using the --tables option:
mysqldump -h 127.0.0.1 -u root --databases foo --tables tbl_name > foodump.sql
Since MemSQL is a distributed database,, we need to tell MemSQL how to shard the data across the cluster. If all your tables have primary keys, MemSQL will automatically use the primary keys to shard them, so you can skip this next step. Otherwise, you need to open up foodump.sql in your favorite editor and either add shard keys or declare the tables as reference tables (for more details, see How to Port Your Applications to MemSQL.
For instance, suppose foodump.sql contains
CREATE TABLE `users` (
`id` bigint(20) NOT NULL,
`username` varchar(11) DEFAULT NULL,
`address` varchar(10)
);
To make this a valid MemSQL table, consider changing it to
CREATE TABLE `users` (
`id` bigint(20) NOT NULL,
`username` int(11) DEFAULT NULL,
`address` varchar(10),
SHARD KEY(`id`)
);
For more information on choosing a shard key, see [Primary Key as the Shard Key]. Once all your tables have either shard key or primary key declarations, you can run the following on the master aggregator:
mysql -h 127.0.0.1 -u root < foodump.sql
All tables and data from users will now be loaded into MemSQL.
