PGAdapter - Liquibase Connection Options

PGAdapter has Pilot Support for Liquibase version v4.12.0 and higher.

Limitations

Pilot Support means that it is possible to use Liquibase with Cloud Spanner PostgreSQL databases, but with limitations. This means that porting an existing application from PostgreSQL to Cloud Spanner will probably require code changes. See Limitations in the Liquibase sample directory for a full list of limitations.

Usage

Start PGAdapter

First start PGAdapter:

export GOOGLE_APPLICATION_CREDENTIALS=/path/to/credentials.json
docker pull gcr.io/cloud-spanner-pg-adapter/pgadapter
docker run \
  -d -p 5432:5432 \
  -v ${GOOGLE_APPLICATION_CREDENTIALS}:${GOOGLE_APPLICATION_CREDENTIALS}:ro \
  -e GOOGLE_APPLICATION_CREDENTIALS \
  gcr.io/cloud-spanner-pg-adapter/pgadapter \
  -p my-project -i my-instance \
  -x

Create databasechangelog and databasechangeloglock Manually

The databasechangeloglock and databasechangelog tables must be created manually, as the DDL script that is automatically generated by Liquibase will try to use the data type timestamp without time zone, which is not supported by Cloud Spanner. The DDL script to create these tables manually can be found in create_database_change_log.sql.

Connect Liquibase to PGAdapter

Liquibase will by default use DDL transactions when connecting to PostgreSQL databases. This is not supported by Cloud Spanner. Instead, PGAdapter can automatically convert DDL transactions into DDL batches. This requires the following option to be set in the JDBC connection URL:

url: jdbc:postgresql://localhost:5432/liquibase-test?options=-c%20spanner.ddl_transaction_mode=AutocommitExplicitTransaction

See liquibase.properties for an example connection URL.

Run Liquibase

Run Liquibase using for example the Maven plugin:

mvn liquibase:validate

Full Sample and Limitations

This directory contains a full sample of how to work with Liquibase with Cloud Spanner and PGAdapter. The sample readme file also lists the current limitations when working with Liquibase.