Returns a ReadOption that specifies read time, allowing Datastore to return results
from lookups and queries at a particular timestamp. This feature is currently in private
preview.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[],[],null,["# Class ReadOption (2.31.2)\n\nVersion latestkeyboard_arrow_down\n\n- [2.31.2 (latest)](/java/docs/reference/google-cloud-datastore/latest/com.google.cloud.datastore.ReadOption)\n- [2.31.1](/java/docs/reference/google-cloud-datastore/2.31.1/com.google.cloud.datastore.ReadOption)\n- [2.30.0](/java/docs/reference/google-cloud-datastore/2.30.0/com.google.cloud.datastore.ReadOption)\n- [2.29.1](/java/docs/reference/google-cloud-datastore/2.29.1/com.google.cloud.datastore.ReadOption)\n- [2.28.2](/java/docs/reference/google-cloud-datastore/2.28.2/com.google.cloud.datastore.ReadOption)\n- [2.27.1](/java/docs/reference/google-cloud-datastore/2.27.1/com.google.cloud.datastore.ReadOption)\n- [2.26.4](/java/docs/reference/google-cloud-datastore/2.26.4/com.google.cloud.datastore.ReadOption)\n- [2.25.2](/java/docs/reference/google-cloud-datastore/2.25.2/com.google.cloud.datastore.ReadOption)\n- [2.24.3](/java/docs/reference/google-cloud-datastore/2.24.3/com.google.cloud.datastore.ReadOption)\n- [2.23.0](/java/docs/reference/google-cloud-datastore/2.23.0/com.google.cloud.datastore.ReadOption)\n- [2.22.0](/java/docs/reference/google-cloud-datastore/2.22.0/com.google.cloud.datastore.ReadOption)\n- [2.21.3](/java/docs/reference/google-cloud-datastore/2.21.3/com.google.cloud.datastore.ReadOption)\n- [2.20.2](/java/docs/reference/google-cloud-datastore/2.20.2/com.google.cloud.datastore.ReadOption)\n- [2.19.2](/java/docs/reference/google-cloud-datastore/2.19.2/com.google.cloud.datastore.ReadOption)\n- [2.18.5](/java/docs/reference/google-cloud-datastore/2.18.5/com.google.cloud.datastore.ReadOption)\n- [2.17.6](/java/docs/reference/google-cloud-datastore/2.17.6/com.google.cloud.datastore.ReadOption) \n\n public abstract class ReadOption implements Serializable\n\nSpecifies options for read operations in Datastore, namely getting/fetching entities and running\nqueries. \n\nInheritance\n-----------\n\n[java.lang.Object](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html) \\\u003e ReadOption \n\nImplements\n----------\n\n[Serializable](https://docs.oracle.com/javase/8/docs/api/java/io/Serializable.html) \n\nInherited Members\n-----------------\n\n[Object.clone()](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#clone--) \n[Object.equals(Object)](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#equals-java.lang.Object-) \n[Object.finalize()](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#finalize--) \n[Object.getClass()](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#getClass--) \n[Object.hashCode()](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#hashCode--) \n[Object.notify()](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#notify--) \n[Object.notifyAll()](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#notifyAll--) \n[Object.toString()](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#toString--) \n[Object.wait()](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait--) \n[Object.wait(long)](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-) \n[Object.wait(long,int)](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-int-)\n\nStatic Methods\n--------------\n\n### eventualConsistency()\n\n public static ReadOption.EventualConsistency eventualConsistency()\n\nReturns a `ReadOption` that specifies eventual consistency, allowing Datastore to return\nstale results from gets, fetches, and ancestor queries.\n\n### readTime(Timestamp time)\n\n public static ReadOption.ReadTime readTime(Timestamp time)\n\n| **Beta**\n|\n| This feature is covered by the [Pre-GA Offerings Terms](/terms/service-terms#1) of the Terms of Service. Pre-GA libraries might have limited support, and changes to pre-GA libraries might not be compatible with other pre-GA versions. For more information, see the launch stage descriptions.\n\nReturns a `ReadOption` that specifies read time, allowing Datastore to return results\nfrom lookups and queries at a particular timestamp. This feature is currently in private\npreview.\n\n### transactionId(ByteString transactionId)\n\n public static ReadOption transactionId(ByteString transactionId)\n\n| **Internal Only**: This feature is not stable for application use.\n\nReturns a `ReadOption` that specifies transaction id, allowing Datastore to execute a\n[Query](/java/docs/reference/google-cloud-datastore/latest/com.google.datastore.v1.Query) in this transaction.\n\n### transactionId(String transactionId)\n\n public static ReadOption transactionId(String transactionId)\n\n| **Internal Only**: This feature is not stable for application use.\n\nReturns a `ReadOption` that specifies transaction id, allowing Datastore to execute a\n[Query](/java/docs/reference/google-cloud-datastore/latest/com.google.datastore.v1.Query) in this transaction."]]
