GAE python NDB 投影查询在开发中工作但不在生产中 [英] GAE python NDB projection query working in development but not in production

问题描述

我一直在撞墙，因为我的 Google App Engine python 项目有一个非常简单的 NDB 投影查询，它在我的本地机器上运行良好，但在部署到生产时神秘地失败了.

I've been hitting my head against the wall because my Google App Engine python project has a very simple NDB projection query which works fine on my local machine, but mysteriously fails when deployed to production.

更神秘……作为测试，我在另一个属性上添加了相同的投影，它在开发和生产中都有效！请问有人可以帮忙吗?！以下是更多详细信息:

Adding to the mystery... as a test I added an identical projection on another property, and it works in both dev and production! Could anyone help please?! Here are more details:

我有以下代表费用的实体:

I have the following entity that represents an expense:

class Entry(ndb.Model):
    datetime = ndb.DateTimeProperty(indexed=True, required=True)
    amount = ndb.IntegerProperty(indexed=False, required=True)
    payee = ndb.StringProperty(indexed=True, required=True) 
    comment = ndb.StringProperty(indexed=False)
    # ...

稍后在代码中，我正在对 Entry.payee 进行投影(以获取所有收款人的列表).作为测试，我还在 Entry.datetime 上添加了一个投影:

Later on in the code I am doing a projection on Entry.payee (to get a list of all payees). As a test I also added a projection on Entry.datetime:

log_msg = '' # For passing debug info to the browser

payeeObjects = Entry.query(ancestor=exp_traq_key(exp_traq_name), projection=[Entry.payee]).fetch()
payees = []
for obj in payeeObjects:
    payees.append(obj.payee)
log_msg += '%d payees: %s' % (len(payees), str(payees))

log_msg += ' ------------------- ' # a visual separator

dtObjects = Entry.query(ancestor=exp_traq_key(exp_traq_name), projection=[Entry.datetime]).fetch()
dts = []
for obj in dtObjects:
    dts.append(obj.datetime)
log_msg += '%d datetimes: %s' % (len(dts), str(dts))

#...other code, including passing log_msg down to the client

这是开发环境中的输出(注意控制台中显示了收款人列表和日期时间列表):

Here's the output in dev environment (notice a list of payees and a list of datetimes are displayed in console):

这是部署到应用引擎时的输出.我无法让它返回收款人列表.它一直返回一个空列表，即使在开发中它返回列表很好:

And here's the output when deployed to app engine. I can't get it to return a list of payees. It keeps returning an empty list even though in dev it returns the list fine:

我已确保在 GAE 上正确设置了索引:

I've ensured that I have the indexes properly set up on GAE:

请帮忙！

2018-12-05 更新:我在生产中添加了更多条目，他们被选中了！见截图.但是较旧的条目仍然没有返回.

2018-12-05 Update: I added a couple more entries in production and they got picked up! See screenshot. But the older entries are still not being returned.

我的直接反应是数据存储索引需要以某种方式刷新"，以便它可以看到"旧条目.但问题是我昨天删除并重新创建了索引，这意味着它应该有旧条目......所以仍然需要帮助解决这个谜团！

My immediate reaction is that the datastore index needs to be "refreshed" somehow so it can "see" old entries. BUT the thing is I removed and recreated the index yesterday, which means it should have old entries... So still need help resolving this mystery!

推荐答案

我想通了.该死的它根本不直观.我希望 GAE 文档在这一点上做得更好...

I figured it out. Darn it wasn't intuitive at all. I wish GAE documentation was better on this point...

我在生产中的数据存储包含许多以前创建的条目.作为我尝试对 Entry.payee 进行投影的最新代码的一部分，我不得不将 Entry.payee 的定义从未编入索引更改为编入索引，如下所示:

My datastore in production contains a lot of previously created entries. As part of my latest code where I'm trying to do the projection on Entry.payee, I had to change the definition of Entry.payee from unindexed to indexed, like so:

payee = ndb.StringProperty(indexed=True, required=True) # Originally was indexed=False

所以现在所有位于数据存储区的条目都被投影查询忽略，因为收款人的索引忽略了这些条目.

So now all those entries sitting in the datastore are being ignored by the projection query because the index on payee ignores those entries.

所以我现在需要做的是以某种方式将所有这些旧实体迁移到 indexed=True.

So what I need to do now is somehow migrate all those old entities to be indexed=True.

更新 - 这是我进行此迁移的方式.结果比预期的要简单.

Update - here's how I did this migration. Turned out simpler than expected.

def runPayeeTypeMigration(exp_traq_name):
  Entry.query(ancestor=exp_traq_key(exp_traq_name)).fetch()
  for entry in entries:
    entry.put()

这是通过将所有条目读入更新后的数据结构(Entry.payee 被索引为 True 的数据结构)并将其写回数据存储区来实现的，这样实体现在将被索引.

This works by reading all entries into the updated datastructure (the one where Entry.payee is indexed=True) and writes it back to the datastore, so that the entity will now be indexed.

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