Chapter 3. Migrating data between cache stores

Data Grid provides a Java utility for migrating persistent data between cache stores.

In the case of upgrading Data Grid, functional differences between major versions do not allow backwards compatibility between cache stores. You can use StoreMigrator to convert your data so that it is compatible with the target version.

For example, upgrading to Data Grid 8.0 changes the default marshaller to Protostream. In previous Data Grid versions, cache stores use a binary format that is not compatible with the changes to marshalling. This means that Data Grid 8.0 cannot read from cache stores with previous Data Grid versions.

In other cases Data Grid versions deprecate or remove cache store implementations, such as JDBC Mixed and Binary stores. You can use StoreMigrator in these cases to convert to different cache store implementations.

3.1. Cache store migrator

Data Grid provides the StoreMigrator.java utility that recreates data for the latest Data Grid cache store implementations.

StoreMigrator takes a cache store from a previous version of Data Grid as source and uses a cache store implementation as target.

When you run StoreMigrator, it creates the target cache with the cache store type that you define using the EmbeddedCacheManager interface. StoreMigrator then loads entries from the source store into memory and then puts them into the target cache.

StoreMigrator also lets you migrate data from one type of cache store to another. For example, you can migrate from a JDBC string-based cache store to a RocksDB cache store.

Important

StoreMigrator cannot migrate data from segmented cache stores to:

Non-segmented cache store.
Segmented cache stores that have a different number of segments.

3.2. Configuring the cache store migrator

Use the migrator.properties file to configure properties for source and target cache stores.

Procedure

Create a migrator.properties file.
Configure properties for source and target cache store using the migrator.properties file.
1. Add the source. prefix to all configuration properties for the source cache store.
  Example source cache store
```
source.type=SOFT_INDEX_FILE_STORE
source.cache_name=myCache
source.location=/path/to/source/sifs
source.version=<version>
```
  Important
  For migrating data from segmented cache stores, you must also configure the number of segments using the source.segment_count property. The number of segments must match clustering.hash.numSegments in your Data Grid configuration. If the number of segments for a cache store does not match the number of segments for the corresponding cache, Data Grid cannot read data from the cache store.
2. Add the target. prefix to all configuration properties for the target cache store.
  Example target cache store
```
target.type=SINGLE_FILE_STORE
target.cache_name=myCache
target.location=/path/to/target/sfs.dat
```

3.2.1. Configuration properties for the cache store migrator

Configure source and target cache stores in a StoreMigrator properties.

Table 3.1. Cache Store Type Property
Property	Description	Required/Optional
`type`	Specifies the type of cache store for a source or target cache store. `.type=JDBC_STRING` `.type=JDBC_BINARY` `.type=JDBC_MIXED` `.type=LEVELDB` `.type=ROCKSDB` `.type=SINGLE_FILE_STORE` `.type=SOFT_INDEX_FILE_STORE` `.type=JDBC_MIXED`	Required

Table 3.2. Common Properties
Property	Description	Example Value	Required/Optional
`cache_name`	The name of the cache that you want to back up.	`.cache_name=myCache`	Required
`segment_count`	The number of segments for target cache stores that can use segmentation. The number of segments must match `clustering.hash.numSegments` in the Data Grid configuration. If the number of segments for a cache store does not match the number of segments for the corresponding cache, Data Grid cannot read data from the cache store.	`.segment_count=256`	Optional

Table 3.3. JDBC Properties
Property	Description	Required/Optional
`dialect`	Specifies the dialect of the underlying database.	Required
`version`	Specifies the marshaller version for source cache stores. Set one of the following values: * `8` for Data Grid 7.2.x * `9` for Data Grid 7.3.x * `10` for Data Grid 8.0.x * `11` for Data Grid 8.1.x * `12` for Data Grid 8.2.x * `13` for Data Grid 8.3.x	Required for source stores only.
`marshaller.class`	Specifies a custom marshaller class.	Required if using custom marshallers.
`marshaller.externalizers`	Specifies a comma-separated list of custom `AdvancedExternalizer` implementations to load in this format: `[id]:<Externalizer class>`	Optional
`connection_pool.connection_url`	Specifies the JDBC connection URL.	Required
`connection_pool.driver_class`	Specifies the class of the JDBC driver.	Required
`connection_pool.username`	Specifies a database username.	Required
`connection_pool.password`	Specifies a password for the database username.	Required
`db.disable_upsert`	Disables database upsert.	Optional
`db.disable_indexing`	Specifies if table indexes are created.	Optional
`table.string.table_name_prefix`	Specifies additional prefixes for the table name.	Optional
`table.string.<id\|data\|timestamp>.name`	Specifies the column name.	Required
`table.string.<id\|data\|timestamp>.type`	Specifies the column type.	Required
`key_to_string_mapper`	Specifies the `TwoWayKey2StringMapper` class.	Optional

Note

To migrate from Binary cache stores in older Data Grid versions, change table.string.* to table.binary.\* in the following properties:

source.table.binary.table_name_prefix
source.table.binary.<id\|data\|timestamp>.name
source.table.binary.<id\|data\|timestamp>.type

# Example configuration for migrating to a JDBC String-Based cache store
target.type=STRING
target.cache_name=myCache
target.dialect=POSTGRES
target.marshaller.class=org.example.CustomMarshaller
target.marshaller.externalizers=25:Externalizer1,org.example.Externalizer2
target.connection_pool.connection_url=jdbc:postgresql:postgres
target.connection_pool.driver_class=org.postrgesql.Driver
target.connection_pool.username=postgres
target.connection_pool.password=redhat
target.db.disable_upsert=false
target.db.disable_indexing=false
target.table.string.table_name_prefix=tablePrefix
target.table.string.id.name=id_column
target.table.string.data.name=datum_column
target.table.string.timestamp.name=timestamp_column
target.table.string.id.type=VARCHAR
target.table.string.data.type=bytea
target.table.string.timestamp.type=BIGINT
target.key_to_string_mapper=org.infinispan.persistence.keymappers. DefaultTwoWayKey2StringMapper

Table 3.4. RocksDB Properties
Property	Description	Required/Optional
`location`	Sets the database directory.	Required
`compression`	Specifies the compression type to use.	Optional

# Example configuration for migrating from a RocksDB cache store.
source.type=ROCKSDB
source.cache_name=myCache
source.location=/path/to/rocksdb/database
source.compression=SNAPPY

Table 3.5. SingleFileStore Properties
Property	Description	Required/Optional
`location`	Sets the directory that contains the cache store `.dat` file.	Required

# Example configuration for migrating to a Single File cache store.
target.type=SINGLE_FILE_STORE
target.cache_name=myCache
target.location=/path/to/sfs.dat

Table 3.6. SoftIndexFileStore Properties
Property	Description	Value
Required/Optional	`location`	Sets the database directory.
Required	`index_location`	Sets the database index directory.

# Example configuration for migrating to a Soft-Index File cache store.
target.type=SOFT_INDEX_FILE_STORE
target.cache_name=myCache
target.location=path/to/sifs/database
target.location=path/to/sifs/index

3.3. Migrating Data Grid cache stores

You can use the StoreMigrator to migrate data between cache stores with different Data Grid versions or to migrate data from one type of cache store to another.

Prerequisites

Have a infinispan-tools.jar.
Have the source and target cache store configured in the migrator.properties file.

Procedure

If you built the infinispan-tools.jar from the source code, do the following:
1. Add infinispan-tools.jar to your classpath.
2. Add dependencies for your source and target databases, such as JDBC drivers to your classpath.
3. Specify migrator.properties file as an argument for StoreMigrator.
If you pulled infinispan-tools.jar from the Maven repository, run the following command:
```
mvn exec:java
```

Chapter 3. Migrating data between cache stores

3.1. Cache store migrator

3.2. Configuring the cache store migrator

3.2.1. Configuration properties for the cache store migrator

3.3. Migrating Data Grid cache stores

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