Liquibase前提条件不起作用 [英] Liquibase preconditions not working

问题描述

我正尝试使用liquibase通过dropwizard-migrations跟踪对Postgresql数据库的更改.我希望能够在现有生产数据库上运行迁移，而不是从头开始重建.目前，我正在分阶段进行测试.我已经创建了一个带有前提条件的变更集.

I'm trying to use liquibase to track changes to a postgresql database using dropwizard-migrations. I'd like to be able to run the migration on the existing production database instead of rebuilding from scratch. Right now I'm testing in staging. I've created a changeset with a precondition.

<changeSet id="3" author="me">
    <preConditions onFail="CONTINUE">
        <not>
            <sequenceExists sequenceName="emails_id_seq"/>
        </not>
    </preConditions>
    <createSequence sequenceName="emails_id_seq" startValue="1" incrementBy="1" />
</changeSet>

我的目标是如果序列已经存在，则跳过应用变更集.看起来很简单，但是没有用.

My goal is to skip applying the changeset if the sequence is already there. Seems straightforward, but it's not working.

ERROR [2013-09-13 22:19:22,564] liquibase: Change Set migrations.xml::3::me failed.  Error: Error executing SQL CREATE SEQUENCE emails_id_seq START WITH 1 INCREMENT BY 1: ERROR: relation "emails_id_seq" already exists
! liquibase.exception.DatabaseException: Error executing SQL CREATE SEQUENCE emails_id_seq START WITH 1 INCREMENT BY 1: ERROR: relation "emails_id_seq" already exists

我也尝试过使用MARK_RAN而不是CONTINUE.运气不好.

I've tried using the MARK_RAN instead of CONTINUE too. No luck with that.

推荐答案

我通过运行dropwizard-migrations"fast-forward"命令来解决此问题，如下所示:

I solved this by running the dropwizard-migrations "fast-forward" command as follows:

java -jar hello-world.jar db fast-forward helloworld.yml

这会将下一个变更集标记为已应用，而没有实际应用.您可能需要对每个要快速前进的变更集执行一次此操作.如果您想快速转发所有内容，则还有一个--all标志.

This will mark the next changeset as applied without actually applying it. You may have to do this one time per changeset you want to fast-forward. There is also an --all flag if you want to fast forward everything.

可在此处找到更多详细信息: http://dropwizard.codahale.com/manual/migrations/

More details can be found here: http://dropwizard.codahale.com/manual/migrations/

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