云Firestore事务的限制 [英] Limitations on Cloud Firestore transactions

问题描述

我已阅读有关 Firestore上事务性更新操作的文档

一>。根据配额和限额，交易只有两个限制：

• 交易的最大尺寸：10 MiB


• 交易的时间限制：270秒，空闲到期时间为60秒

没有明确的交易相关限制提及，在交易过程中可以读取和/或修改多少个文档或集合，或者对事务更新发生的集合有任何附加限制。

1. 这是否意味着客户可以对最多500个文档进行事务更新，每个文档都在不同的集合中，只要更新保持在这些限制和其他一般限制内？




2. 如果客户端在事务内部读取多个文档，但只更新其中一个文档 - Fires （静默地）写入未修改的文档（用于序列化等）...所以我必须考虑每秒每写入一次写入的写入限制，即使对于未被客户机明确修改的文档。 p：

PS：我问的原因是数据存储在事务中有25个实体组的限制，并且还看到热点在许多写入事务中只读的实体（文档）。例如，请参阅Dan McGrath的此答案。我只是想知道Datastore的哪些特性可以传递给Firestore，并且在设计Firestore数据库时必须考虑到它。

可以传递给Commit操作的最大文档数量，它定义了500个文档的限制。这是您的交易限制，因为我们需要使用单个提交将所有内容应用于交易。

我不认为无需再进行静默写入来确定文档是否具有

没有相关的限制，相当于25个实体组的限制。

I have read the docs regarding transactional update operations on Firestore. According to Quotas and Limits there are only two limits with regards to transactions:

• Maximum size for a transaction: 10 MiB
• Time limit for a transaction: 270 seconds, with a 60-second idle expiration time

There is no explicitly transaction-related limit mentioned, how many documents or collections can be read and/or modified during the transaction, or if there are any additional constraints on the collections in which the transactional updates happen.

1. Does it mean, a client could do a transactional update on up to 500 documents, each in different collections, as long as the update stays inside these and the other general limits?

2. If a client reads multiple documents inside a transaction, but only updates one of them - does Firestore still (silently) write into the unmodified documents (for serialization or so)... so I have to consider the write-limit of 1 write per document per second even for documents that have not been explicitly modified by the client.

P.S.: The reason I ask is that Datastore has a limit of 25 entity-groups in transactions, and also sees hotspots in entities ("documents") that are read-only inside many write transactions. For example, see this answer by Dan McGrath. I just wonder which of Datastore's characteristics carry over to Firestore and has to be considered when designing a Firestore database.

解决方案

See the line "Maximum number of documents that can be passed to a Commit operation" which defines a limit of 500 documents. This is your transaction limit as we need to apply everything in a transaction using a single commit.

I don't believe silent writes are required anymore to determine if a document has changed in a transaction.

There is no related limit that is equivalent to the 25 entity-group limit.

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