Migrating from SDK2 to SDK3 API

concept

The 3.x API breaks the existing 2.x APIs in order to provide a number of improvements. Collections and Scopes are introduced. The Document class and structure has been completely removed from the API, and the returned value is now Result. Retry behaviour is more proactive, and lazy bootstrapping moves all error handling to a single place. Individual behavior changes across services are explained here.

Fundamentals

Before this guide dives into the language-specific technical component of the migration, it is important to understand the high level changes first. As a migration guide, this document assumes you are familiar with the previous generation of the SDK and does not re-introduce SDK API 2 concepts. We recommend familiarizing yourself with the new SDK first by reading at least the getting started guide, and browsing through the other chapters a little.

Terminology

The concept of a Cluster and a Bucket remain the same, but a fundamental new layer is introduced into the API: Collections and their Scopes. Collections are logical data containers inside a Couchbase bucket that let you group similar data just like a Table does in a relational database — although documents inside a collection do not need to have the same structure. Scopes allow the grouping of collections into a namespace, which is very usfeul when you have multilpe tenants acessing the same bucket. Couchbase Server includes support for collections as a developer preview in version 6.5, and as a first class concept of the programming model from version 7.0.

Note that the SDKs include the feature from SDK 3.0, to allow easier migration.

In the previous SDK generation, particularly with the KeyValue API, the focus has been on the codified concept of a Document. Documents were read and written and had a certain structure, including the id/key, content, expiry (ttl), and so forth. While the server still operates on the logical concept of documents, we found that this model in practice didn’t work so well for client code in certain edge cases. As a result we have removed the Document class/structure completely from the API. The new API follows a clear scheme: each command takes required arguments explicitly, and an option block for all optional values. The returned value is always of type Result. This avoids method overloading bloat in certain languages, and has the added benefit of making it easy to grasp APIs evenly across services.

As an example here is a KeyValue document fetch:

GetResult getResult = collection.get("airline_10", getOptions().timeout(Duration.ofSeconds(3)));

Compare this to a N1QL query:

QueryResult queryResult = cluster.query("select 1=1", queryOptions().timeout(Duration.ofSeconds(3)));

Since documents also fundamentally handled the serialization aspects of content, two new concepts are introduced: the Serializer and the Transcoder. Out of the box the SDKs ship with a JSON serializer which handles the encoding and decoding of JSON. You’ll find the serializer exposes the options for methods like N1QL queries and KeyValue subdocument operations,.

The KV API extends the concept of the serializer to the Transcoder. Since you can also store non-JSON data inside a document, the Transcoder allows the writing of binary data as well. It handles the object/entity encoding and decoding, and if it happens to deal with JSON makes uses of the configured Serializer internally. See the Serialization and Transcoding section below for details.

What to look out for

The SDKs are more proactive in retrying with certain errors and in certain situations, within the timeout budget given by the user — as an example, temporary failures or locked documents are now being retried by default — making it even easier to program against certain error cases. This behavior is customizable in a RetryStrategy, which can be overridden on a per operation basis for maximum flexibility if you need it.

Note, most of the bootstrap sequence is now lazy (happening behind the scenes). For example, opening a bucket is not raising an error anymore, but it will only show up once you perform an actual operation. The reason behind this is to spare the application developer the work of having to do error handling in more places than needed. A bucket can go down 2ms after you opened it, so you have to handle request failures anyway. By delaying the error into the operation result itself, there is only one place to do the error handling. There will still be situations why you want to check if the resource you are accessing is available before continuing the bootstrap; for this, we have the diagnostics and ping commands at each level which allow you to perform those checks eagerly.

Language Specifics

Now that you are familiar with the general theme of the migration, the next sections dive deep into the specifics. First, installation and configuration are covered, then we talk about exception handling, and then each service (i.e. Key/Value, Query,…) is covered separately.

Installation and Configuration

The Java SDK 3.x is available for download from the same resources as the previous generation. Builds can be found on maven central, pre-releases are available from our own maven repository. In addition, a zip file is available with the required jars. Please see the Release Notes for up-to-date information.

Java SDK 3.x has a minimum required Java version of 8, although we recommend running the latest LTS version (i.e. at the time of writing JDK 11) with the highest patch version available.

Note that the transitive dependency list has changed. As a refresher, Java SDK 2 depended on the following artifacts:

com.couchbase.client:core-io
io.reactivex:rxjava
io.opentracing:opentracing-api

SDK 3 depends on the following ones instead:

com.couchbase.client:core-io
io.projectreactor:reactor-core
org.reactivestreams:reactive-streams

Note that the SDK now uses Reactor instead of RxJava and the explicit dependency on OpenTracing is gone. We are now providing support for different tracing backends with additional dependencies that can be pulled in as needed. ReactiveStreams is a transitive dependency of Reactor and provides interoperability code so you can use other reactive streams implementations as well.

If you are pulling in the SDK through a package manager (recommended), all dependencies will be resolved for you automatically. Otherwise please download the zip file and adjust your jar files accordingly.

Configuring the Environment

The fundamental semantics of the CouchbaseEnvironment from SDK 2 remain the same, although somewhat more flexible, with its configuration cleaned up to be more easily discoverable. The CouchbaseEnvironment has been renamed to ClusterEnvironment and can be customized through a builder:

// SDK 2 custom KV timeout
CouchbaseEnvironment env = DefaultCouchbaseEnvironment
  .builder()
  .kvTimeout(TimeUnit.SECONDS.toMillis(5))
  .build();

// SDK 3 equivalent
ClusterEnvironment env = ClusterEnvironment.builder()
    .timeoutConfig(TimeoutConfig.kvTimeout(Duration.ofSeconds(5))).build();

Similar to SDK 2, if you create your own ClusterEnvironment the SDK will not shut it down for you — you need to do this manually at the end of the program lifetime:

ClusterEnvironment env = ClusterEnvironment.create();
Cluster cluster = Cluster.connect("127.0.0.1",
    // pass the custom environment through the cluster options
    clusterOptions("Administrator", "password").environment(env));

// first disconnect, then shutdown the environment
cluster.disconnect();
env.shutdown();

If a default environment is used, the default settings can still be customized through either the connection string or system properties. The SDK has elaborate reflection logic in place to parse "flat" string values and apply them to the builder, which means that you can now configure more properties than in SDK 2. Note that the property paths have changed.

// Will set the max http connections to 23
System.setProperty("com.couchbase.env.io.maxHttpConnections", "23");
Cluster.connect("127.0.0.1", "Administrator", "password");

// This is equivalent to
ClusterEnvironment env = ClusterEnvironment.builder().ioConfig(IoConfig.maxHttpConnections(23)).build();

// Will set the max http connections to 23
Cluster.connect("127.0.0.1?io.maxHttpConnections=23", "Administrator", "password");

// This is equivalent to
ClusterEnvironment env = ClusterEnvironment.builder().ioConfig(IoConfig.maxHttpConnections(23)).build();

The paths for each config start with the pattern com.couchbase.env. followed by either a toplevel or nested config. IoConfig is under the io path, similar to TimeoutConfig under timeout. So, if you want to modify a KV timeout you can use the com.couchbase.env.timeout.kvTimeout path. See the configuration section for full specifics.

At the end of this guide you’ll find a reference that describes the SDK 2 environment options and their SDK 3 equivalents where applicable.

Authentication

Since SDK 2 supports Couchbase Server clusters older than 5.0, it had to support both Role-Based access control as well as bucket-level passwords. The minimum cluster version supported by SDK 3 is Server 5.0, which means that only RBAC is supported. This is why you can set the username and password when directly connecting:

Cluster.connect("127.0.0.1", "Administrator", "password");

This is just a shorthand for:

Cluster.connect("127.0.0.1", clusterOptions(PasswordAuthenticator.create("Administrator", "password")));

The reason why you can pass in a specific authenticator is that you can also use the same approach to configure certificate-based authentication:

KeyManagerFactory keyManagerFactory = null; // configure certificates per documentation
Cluster.connect("127.0.0.1",
    clusterOptions(CertificateAuthenticator.fromKeyManagerFactory(() -> keyManagerFactory)));

Please see the documentation on certificate-based authentication for detailed information on how to configure this properly.

Connection Lifecycle

From a high-level perspective, bootstrapping and shutdown is very similar to SDK 2. One notable difference is that the Collection is introduced and that the individual methods like bucket immediately return, and do not throw an exception. Compare SDK 2: the openBucket method would not work if it could not open the bucket.

The reason behind this change is that even if a bucket can be opened, a millisecond later it may not be available any more. All this state has been moved into the actual operation so there is only a single place where the error handling needs to take place. This simplifies error handling and retry logic for an application.

In SDK 2, you connected, opened a bucket, performed a KV op, and disconnected like this:

Cluster cluster = Cluster.connect(connectionString, username, password);

Bucket bucket = cluster.bucket(bucketName);

GetResult getResult = bucket.defaultCollection().get("airline_10");

cluster.disconnect();

Here is the SDK 3 equivalent:

Cluster cluster = Cluster.connect("127.0.0.1", "Administrator", "password");
Bucket bucket = cluster.bucket("travel-sample");
Scope scope = bucket.scope("inventory");
Collection collection = scope.collection("airline");

GetResult getResult = collection.get("airline_10");

cluster.disconnect();

Collections are generally available from Couchbase Server version 7.0, which the SDK is already compatible with. If you are using a Couchbase Server version which does not support Collections, always use the defaultCollection() method to access the KV API; it will map to the full bucket.

You’ll notice that bucket(String) returns immediately, even if the bucket resources are not completely opened. This means that the subsequent get operation may be dispatched even before the connection is opened in the background. The SDK will handle this case transparently, and reschedule the operation until the bucket is opened properly. This also means that if a bucket could not be opened (say, because no server was reachable) the operation will time out. Please check the logs to see the cause of the timeout (in this case, you’ll see socket connect rejections).

Also note, you will now find Query, Search, and Analytics at the Cluster level. This is where they logically belong. If you are using Couchbase Server 6.5 or later, you will be able to perform cluster-level queries even if no bucket is open. If you are using an earlier version of the cluster you must open at least one bucket, otherwise cluster-level queries will fail.

Serialization and Transcoding

In SDK 2 the main method to control transcoding was through providing different Document instances (which in turn had their own transcoder associated), such as the JsonDocument. This only worked for the KV APIs though — Query, Search, Views, and other services exposed their JSON rows/hits in different ways. All of this has been unified in SDK 3 under a single concept: serializers and transcoders.

By default, all KV APIs transcode to and from JSON — you can also provide java POJOs which you couldn’t in the past. JsonObject and JsonArray are still available, like in SDK 2:

// SDK 2 upsert and get
JsonDocument upsertResult = bucket.upsert(
  JsonDocument.create("mydoc-id", JsonObject.empty())
);
JsonDocument getResult = bucket.get("mydoc-id");

MutationResult upsertResult = collection.upsert("mydoc-id", JsonObject.create());
GetResult getResult = collection.get("mydoc-id");

If you want to write already-encoded JSON, instead of using the RawJsonDocument you now need to use the RawJsonTranscoder.INSTANCE:

byte[] content = "{}".getBytes(StandardCharsets.UTF_8);
MutationResult upsertResult = collection.upsert("mydoc-id", content,
    upsertOptions().transcoder(RawJsonTranscoder.INSTANCE));

Here is a mapping table from the SDK 2 Document types to the new transcoder types:

Table 1. SDK 2.x Document vs. SDK 3.x Transcoder
SDK 2	SDK 3
`JsonDocument`	`JsonTranscoder` (default)
`JsonArrayDocument`	`JsonTranscoder` (default)
`JsonBooleanDocument`	`JsonTranscoder` (default)
`JsonLongDocument`	`JsonTranscoder` (default)
`JsonStringDocument`	`JsonTranscoder` (default)
`JsonDoubleDocument`	`JsonTranscoder` (default)
`LegacyDocument`	removed
`RawJsonDocument`	`RawJsonTranscoder`
`SerializableDocument`	`SerializableTranscoder`
`StringDocument`	`RawStringTranscoder`
`ByteArrayDocument`	`RawBinaryTranscoder`
`BinaryDocument`	`RawBinaryTranscoder`
`EntityDocument`	`JsonTranscoder` (default)

The LegacyDocument in SDK 2 was in place to support SDK 1, so it has been removed. Serializers and transcoders can also be customized and overwritten on a per-operation basis, please see the appropriate documentation section for details.

The JSON Transcoders use a Serializer underneath. While a transcoder can handle many different storage types, the serializer is specialized for JSON encoding and decoding. On all JSON-only APIs (i.e. Sub-doc, Query, Search,…) you’ll only find a Serializer, not a Transcoder, in the operation options. Usually there is no need to override it unless you want to provide your own implementation (i.e. if you have your own POJO mapping json logic in place, and want to reuse it).

Exception Handling

How to handle exceptions is unchanged from SDK 2. You should still use try/catch on the blocking APIs and the corresponding reactive/async methods on the other APIs. There have been changes made in the following areas:

Exception hierachy and naming.
Proactive retry where possible.

Exception hierachy

The exception hierachy is now flat and unified under a CouchbaseException. Each CouchbaseException has an associated ErrorContext which is populated with as much information as possible and then dumped alongside the stack trace if an error happens.

Here is an example of the error context if a N1QL query is performed with an invalid syntax (i.e. select 1= from):

Exception in thread "main" com.couchbase.client.core.error.ParsingFailedException: Parsing of the input failed {"completed":true,"coreId":1,"errors":[{"code":3000,"message":"syntax error - at from"}],"idempotent":false,"lastDispatchedFrom":"127.0.0.1:62253","lastDispatchedTo":"127.0.0.1:8093","requestId":3,"requestType":"QueryRequest","retried":11,"retryReasons":["ENDPOINT_TEMPORARILY_NOT_AVAILABLE","BUCKET_OPEN_IN_PROGRESS"],"service":{"operationId":"9111b961-e585-42f2-9cab-e1501da7a40b","statement":"select 1= from","type":"query"},"timeoutMs":75000,"timings":{"dispatchMicros":15599,"totalMicros":1641134}}

The expectation is that the application catches the CouchbaseException and deals with it as an unexpected error (e.g. logging with subsequent bubbling up of the exception or failing). In addition to that, each method exposes exceptions that can be caught separately if needed. As an example, consider the javadoc for the Collection.get API:

   * @throws DocumentNotFoundException the given document id is not found in the collection.
   * @throws TimeoutException if the operation times out before getting a result.
   * @throws CouchbaseException for all other error reasons (acts as a base type and catch-all).

These exceptions extend CouchbaseException, but both the TimeoutException and the DocumentNotFoundException can be caught individually if specific logic should be executed to handle them.

Proactive Retry

One reason why the APIs do not expose a long list of exceptions is that the SDK now retries as many operations as it can if it can do so safely. This depends on the type of operation (idempotent or not), in which state of processing it is (already dispatched or not), and what the actual response code is if it arrived already. As a result, many transient cases — such as locked documents, or temporary failure — are now retried by default and should less often impact applications. It also means, when migrating to the new SDK API, you may observe a longer period of time until an error is returned by default.

Operations are retried by default as described above with the default BestEffortRetryStrategy. Like in SDK 2 you can configure fail-fast retry strategies to not retry certain or all operations. The RetryStrategy interface has been extended heavily in SDK 3 — please see the error handling documentation.

When migrating your SDK 2 exception handling code to SDK 3, make sure to wrap every call with a catch for CouchbaseException (or let it bubble up immediately). You can likely remove your user-level retry code for temporary failures, backpressure exception, and so on. One notable exception from this is the CasMismatchException, which is still thrown since it requires more app-level code to handle (most likely identical to SDK 2).

Logging and Events

Configuring and consuming logs has not greatly changed. The SDK still uses SLF4J, if found on the classpath, and if not reverts back to the JDK logger (it can also be configured to log to stderr instead). The big difference is that the EventBus (also present in SDK 2) has been made much more powerful — and all logs are sent as events through it. The LoggingEventConsumer being one of the potential consumers, and turning events into log lines.

The biggest impact you’ll see from it is that the log messages now look very structured and contain contextual information where possible.

13:36:46 INFO  [com.couchbase.node:470] [com.couchbase.node][NodeConnectedEvent] Node connected {"coreId":1,"managerPort":"8091","remote":"127.0.0.1"}
13:36:46 INFO  [com.couchbase.core:470] [com.couchbase.core][BucketOpenedEvent][393161µs] Opened bucket "travel-sample" {"coreId":1}

Notice the package path (which you can also filter on if needed), the event name, an optional time that it took to perform the operation, the message and surrounding context. This makes it easier to debug potential problems but also allows consuming all the events and feeding them in other monitoring systems without having to round-trip a file log. Please see the logging documentation for further information.

Migrating Services

The following section discusses each service in detail and covers specific bits that have not been covered by the more generic sections above.

Key Value

The Key/Value (KV) API is now located under the Collection interface, so even if you do not use CollectionsExample, the defaultCollection() needs to be opened in order to access it.

The following table describes the SDK 2 KV APIs and where they are now located in SDK 3:

Table 2. SDK 2.x KV API vs. SDK 3.x KV API
SDK 2	SDK 3
`Bucket.upsert`	`Collection.upsert`
`Bucket.get`	`Collection.get`
`Bucket.exists`	`Collection.exists`
`Bucket.getFromReplica`	`Collection.getAnyReplica` and `Collection.getAllReplicas`
`Bucket.getAndLock`	`Collection.getAndLock`
`Bucket.getAndTouch`	`Collection.getAndTouch`
`Bucket.insert`	`Collection.insert`
`Bucket.upsert`	`Collection.upsert`
`Bucket.replace`	`Collection.replace`
`Bucket.remove`	`Collection.remove`
`Bucket.unlock`	`Collection.unlock`
`Bucket.touch`	`Collection.touch`
`Bucket.lookupIn`	`Collection.lookupIn`
`Bucket.mutateIn`	`Collection.mutateIn` (see note about store semantics)
`Bucket.counter`	`BinaryCollection.increment` and `BinaryCollection.decrement`
`Bucket.append`	`BinaryCollection.append`
`Bucket.prepend`	`BinaryCollection.prepend`

To migrate code that called MutateInBuilder.upsertDocument(true), specify the operation’s store semantics. For example:

SDK 2

bucket.mutateIn("myDocument")
    .insert("color", "blue")
    .upsertDocument(true)
    .execute();

SDK 3

collection.mutateIn(
    "myDocument",
    Collections.singletonList(MutateInSpec.insert("color", "blue")),
    MutateInOptions.mutateInOptions()
        .storeSemantics(StoreSemantics.UPSERT)
);

In addition, the datastructure APIs have been renamed and moved:

Table 3. Datastructure API Changes
SDK 2	SDK 3
`Bucket.mapAdd`	`Collection.map`
`Bucket.mapGet`	`Collection.map`
`Bucket.mapRemove`	`Collection.map`
`Bucket.mapSize`	`Collection.map`
`Bucket.listGet`	`Collection.list`
`Bucket.listAppend`	`Collection.list`
`Bucket.listRemove`	`Collection.list`
`Bucket.listPrepend`	`Collection.list`
`Bucket.listSet`	`Collection.list`
`Bucket.listSize`	`Collection.list`
`Bucket.setAdd`	`Collection.set`
`Bucket.setContains`	`Collection.set`
`Bucket.setRemove`	`Collection.set`
`Bucket.setSize`	`Collection.set`
`Bucket.queuePush`	`Collection.queue`
`Bucket.queuePop`	`Collection.queue`

There are two important API changes:

On the request side, overloads have been reduced and moved under a Options block
On the response side, the return types have been unified.

The signatures now look very similar. The concept of the Document as a type is gone in SDK 3 and instead you need to pass in the properties explicitly. This makes it very clear what is returned, especially on the response side.

Thus, the get method does not return a Document but a GetResult instead, and the upsert does not return a Document but a MutationResult. Each of those results only contains the field that the specific method can actually return, making it impossible to accidentally try to access the expiry on the Document after a mutation, for example.

Instead of having many overloads, all optional params are now part of the Option block. All required params are still part of the method signature, making it clear what is required and what is not (or has default values applied if not overridden).

The timeout can be overridden on every operation and now takes a Duration from java 8. Compare SDK 2 and SDK 3 custom timeout setting:

// SDK 2 custom timeout
bucket.get("mydoc-id", 5, TimeUnit.SECONDS);

// SDK 3 custom timeout
GetResult getResult = collection.get("mydoc-id", getOptions().timeout(Duration.ofSeconds(5)));

In SDK 2, the getFromReplica method had a ReplicaMode argument which allowed you to customize its behavior on how many replicas should be reached. We have identified this as a potential source of confusion and as a result split it up in two methods that simplify usage significantly. There is now a getAllReplicas method and a getAnyReplica method.

getAllReplicas asks the active node and all available replicas and returns the results as a stream.
getAnyReplica uses getAllReplicas, and returns the first result obtained.

Unless you want to build some kind of consensus between the different replica responses, we recommend getAnyReplica for a fallback to a regular get when the active node times out.

Operations which cannot be performed on JSON documents have been moved to the BinaryCollection, accessible through Collection.binary(). These operations include append, prepend, increment, and decrement (previously called counter in SDK 2). These operations should only be used against non-json data. Similar functionality is available through mutateIn on JSON documents.

Query

N1QL querying is now available at the Cluster level instead of the bucket level, because you can also write N1QL queries that span multiple buckets. Compare a simple N1QL query from SDK 2 with its SDK 3 equivalent:

// SDK 2 simple query
N1qlQueryResult queryResult = bucket.query(N1qlQuery.simple("select * from `travel-sample` limit 10"));
for (N1qlQueryRow row : queryResult) {
  JsonObject value = row.value();
  // ...
}

// SDK 3 simple query
QueryResult queryResult = cluster.query("select * from `travel-sample`.inventory.airport limit 10");
for (JsonObject value : queryResult.rowsAsObject()) {
  // ...
}

Note that there is no N1qlQuery.simple any more — parameter option have been moved to the queryOptions() for consistency reasons. The following shows how to do named and positional parameters in SDK 2, and their SDK 3 counterparts:

// SDK 2 named parameters
bucket.query(N1qlQuery.parameterized(
  "select * from bucket where type = $type",
  JsonObject.create().put("type", "airport")
));

// SDK 2 positional parameters
bucket.query(N1qlQuery.parameterized(
  "select * from bucket where type = $1",
  JsonArray.from("airport")
));

// SDK 3 named parameters
cluster.query("select * from `travel-sample`.inventory.airport where airportname = $name",
    queryOptions().parameters(JsonObject.create().put("name", "Calais Dunkerque")));

// SDK 3 positional parameters
cluster.query("select * from `travel-sample`.inventory.airport where airportname = $1",
    queryOptions().parameters(JsonArray.from("Calais Dunkerque")));

If you want to use prepared statements, the adhoc() method is still available on the QueryOptions, alongside every other option that used to be exposed on the SDK 2 Query options.

Much of the non-row metadata has been moved into a specific QueryMetaData section:

Table 4. Query Metadata Changes
SDK 2	SDK 3
`N1qlQueryResult.signature`	`QueryResult.metaData.signature`
`N1qlQueryResult.info`	`QueryResult.metaData.metrics`
`N1qlQueryResult.profileInfo`	`QueryResult.metaData.profile`
`N1qlQueryResult.parseSuccess`	removed
`N1qlQueryResult.finalSuccess`	removed
`N1qlQueryResult.status`	`QueryResult.metaData.status`
`N1qlQueryResult.errors`	throws an Exception on `QueryResult`
`N1qlQueryResult.requestId`	`QueryResult.metaData.requestId`
`N1qlQueryResult.clientContextId`	`QueryResult.metaData.clientContextId`

It is no longer necessary to check for a specific error in the stream: if an error happened during processing it will throw an exception at the top level of the query. The reactive streaming API will terminate the rows' Flux with an exception as well as soon as it is discovered. This makes error handling much easier in both the blocking and non-blocking cases.

While in SDK 2 you had to manually check for errors (otherwise you’d get an empty row collection):

QueryResult queryResult = cluster.query("select 1=");
if (!queryResult.metaData().warnings().isEmpty()) {
  // errors contain [{"msg":"syntax error - at end of input","code":3000}]
}

In SDK 3 the top level query method will throw an exception:

Exception in thread "main" com.couchbase.client.core.error.ParsingFailedException: Parsing of the input failed {"completed":true,"coreId":1,"errors":[{"code":3000,"message":"syntax error - at end of input"}],"idempotent":false,"lastDispatchedFrom":"127.0.0.1:51703","lastDispatchedTo":"127.0.0.1:8093","requestId":5,"requestType":"QueryRequest","retried":0,"service":{"operationId":"1c623a77-196a-4890-96cd-9d4f3f596477","statement":"select 1=","type":"query"},"timeoutMs":75000,"timings":{"dispatchMicros":13798,"totalMicros":70789}}
	at com.couchbase.client.java.AsyncUtils.block(AsyncUtils.java:51)
	at com.couchbase.client.java.Cluster.query(Cluster.java:225)

Not only does it throw a CouchbaseException, it also tries to map it to a specific exception type and include extensive contextual information for a better troubleshooting experience.

DSL Deprecation

The fluent API feature in SDK 2.x was found not to scale well for larger queries, nor for SQL++. For these reasons it is not amongst the features carried over to SDK 3.x.

In most cases, a simple string statement is the best replacement.

Analytics

Analytics querying, like N1QL, is also moved to the Cluster level: it is now accessible through the Cluster.analyticsQuery method. As with the Query service, parameters for the Analytics queries have moved into the AnalyticsOptions:

// SDK 3 simple analytics query
AnalyticsResult analyticsResult = cluster.analyticsQuery("select * from `travel-sample`.inventory.airport limit 10");
for (JsonObject value : analyticsResult.rowsAsObject()) {
  // ...
}

// SDK 3 named parameters for analytics
cluster.analyticsQuery("select * from `travel-sample`.inventory.airport where airportname = $name",
    analyticsOptions().parameters(JsonObject.create().put("name", "Calais Dunkerque")));

// SDK 3 positional parameters for analytics
cluster.analyticsQuery("select * from `travel-sample`.inventory.airport where airportname = $1",
    analyticsOptions().parameters(JsonArray.from("Calais Dunkerque")));

Also, errors will now be thrown as top level exceptions and it is no longer necessary to explicitly check for errors:

// SDK 2 error check
AnalyticsQueryResult analyticsQueryResult = b1.query(AnalyticsQuery.simple("select * from foo"));
if (!analyticsQueryResult.errors().isEmpty()) {
  // errors contain [{"msg":"Cannot find dataset foo in dataverse Default nor an alias with name foo! (in line 1, at column 15)","code":24045}]
}

// SDK 3 top level exception
com.couchbase.client.core.error.DatasetNotFoundException: The analytics dataset is not found {"completed":true,"coreId":1,"errors":[{"code":24045,"message":"Cannot find dataset foo in dataverse Default nor an alias with name foo! (in line 1, at column 15)"}],"idempotent":false,"lastDispatchedFrom":"127.0.0.1:51942","lastDispatchedTo":"127.0.0.1:8095","requestId":5,"requestType":"AnalyticsRequest","retried":0,"service":{"operationId":"80265061-62e0-4c35-860f-a07a97e1a5ee","priority":0,"statement":"select * from foo","type":"analytics"},"timeoutMs":75000,"timings":{"dispatchMicros":27005,"totalMicros":89888}}
	at com.couchbase.client.java.AsyncUtils.block(AsyncUtils.java:51)
	at com.couchbase.client.java.Cluster.analyticsQuery(Cluster.java:250)

Search

The Search API has changed a bit in SDK 3 so that it aligns with the other query APIs. The type of queries have stayed the same, but all optional parameters moved into SearchOptions. Also, similar to the other query APIs, it is now available at the Cluster level.

Here is a SDK 2 Search query with some options, and its SDK 3 equivalent:

// SDK 2 search query
SearchQueryResult searchResult = bucket.query(new SearchQuery(
  "indexname",
  SearchQuery.queryString("airports")).limit(5).fields("a", "b", "c"),
  2,
  TimeUnit.SECONDS
);
for (SearchQueryRow row : searchResult.hits()) {
  // ...
}

// SDK 3 search query
SearchResult searchResult = cluster.searchQuery("travel-sample-index", SearchQuery.queryString("swanky"),
    searchOptions().timeout(Duration.ofSeconds(2)).limit(5).fields("description", "type", "city"));
for (SearchRow row : searchResult.rows()) {
  // ...
}

Error handling for streaming is handled differently. While fatal errors will still raise top-level exceptions, any errors that happend during streaming (for example if one node is down, and only partial results are returned) they will not terminate the result. The reasoning behind this is that usually with search results, having partial results is better than none.

Here is a top level exception, for the index does not exist:

com.couchbase.client.core.error.SearchIndexNotFoundException: The search index is not found on the server {"completed":true,"coreId":1,"httpStatus":400,"idempotent":true,"lastDispatchedFrom":"127.0.0.1:53280","lastDispatchedTo":"127.0.0.1:8094","requestId":5,"requestType":"SearchRequest","retried":0,"service":{"indexName":"myindex","type":"search"},"status":"INVALID_ARGS","timeoutMs":75000,"timings":{"dispatchMicros":12741,"totalMicros":66262}}
	at com.couchbase.client.java.AsyncUtils.block(AsyncUtils.java:51)
	at com.couchbase.client.java.Cluster.searchQuery(Cluster.java:275)

If you want to be absolutely sure that you didn’t get only partial data, you can check the error map:

SearchResult searchResult = cluster.searchQuery("travel-sample-index", SearchQuery.queryString("swanky"));
SearchMetaData searchMetaData = searchResult.metaData();
if (searchMetaData.errors() == null || searchMetaData.errors().isEmpty()) {
  // no errors present, so full data got returned
}

Views

Views have stayed at the Bucket level, because it does not have the concept of CollectionsExample and is scoped at the bucket level on the server as well. The API has stayed mostly the same, the most important change is that staleness is unified under the ViewConsistency enum.

Table 5. View Staleness Mapping
SDK 2	SDK 3
`Stale.TRUE`	`ViewScanConsistency.NOT_BOUNDED`
`Stale.FALSE`	`ViewScanConsistency.REQUEST_PLUS`
`Stale.UPDATE_AFTER`	`ViewScanConsistency.UPDATE_AFTER`

Compare this SDK 2 view query with its SDK 3 equivalent:

// SDK 2 view query
ViewResult query = bucket.query(
  ViewQuery.from("design", "view").limit(5).skip(2),
  10,
  TimeUnit.SECONDS
);
for (ViewRow row : query) {
  // ...
}

// SDK 3 view query
ViewResult viewResult = bucket.viewQuery("dev_landmarks-by-name", "by_name",
    viewOptions().limit(5).skip(2).timeout(Duration.ofSeconds(10)));
for (ViewRow row : viewResult.rows()) {
  // ...
}

Exceptions are exclusively raised at the top level: for example, if the design document is not found:

com.couchbase.client.core.error.ViewNotFoundException: The queried view is not found on the server {"completed":true,"coreId":1,"httpStatus":404,"idempotent":true,"lastDispatchedFrom":"127.0.0.1:53474","lastDispatchedTo":"127.0.0.1:8092","requestId":5,"requestType":"ViewRequest","retried":0,"service":{"bucket":"travel-sample","designDoc":"foo","development":false,"type":"views","viewName":"bar"},"status":"NOT_FOUND","timeoutMs":75000,"timings":{"dispatchMicros":77572,"totalMicros":189389},"viewError":"not_found","viewErrorReason":"Design document _design/foo not found"}
	at com.couchbase.client.java.AsyncUtils.block(AsyncUtils.java:51)
	at com.couchbase.client.java.Bucket.viewQuery(Bucket.java:182)

Management APIs

In SDK 2, the management APIs were centralized in the ClusterManager at the cluster level and the BucketManager at the bucket level. Since SDK 3 provides more management APIs, they have been split up in their respective domains. So for example when in SDK 2 you needed to remove a bucket you would call ClusterManager.removeBucket you will now find it under BucketManager.dropBucket. Also, creating a N1QL index now lives in the QueryIndexManager, which is accessible through the Cluster.

The following table provides a mapping from the SDK 2 management APIs to those of SDK 3:

Table 6. SDK 2.x vs SDK 3.x ClusterManager
SDK 2	SDK 3
`ClusterManager.info`	removed
`ClusterManager.getBuckets`	`BucketManager.getAllBuckets`
`ClusterManager.getBucket`	`BucketManager.getBucket`
`ClusterManager.hasBucket`	removed
`ClusterManager.insertBucket`	`BucketManager.createBucket`
`ClusterManager.updateBucket`	`BucketManager.updateBucket`
`ClusterManager.removeBucket`	`BucketManager.dropBucket`
`ClusterManager.upsertUser`	`UserManager.upsertUser`
`ClusterManager.removeUser`	`UserManager.dropUser`
`ClusterManager.getUsers`	`UserManager.getAllUsers`
`ClusterManager.getUser`	`UserManager.getUser`
`ClusterManager.apiClient`	removed

Table 7. SDK 2.x vs SDK 3.x BucketManager
SDK 2	SDK 3
`BucketManager.info`	removed
`BucketManager.flush`	`BucketManager.flushBucket`
`BucketManager.getDesignDocuments`	`ViewIndexManager.getAllDesignDocuments`
`BucketManager.getDesignDocument`	`ViewIndexManager.getDesignDocument`
`BucketManager.insertDesignDocument`	`ViewIndexManager.upsertDesignDocument`
`BucketManager.upsertDesignDocument`	`ViewIndexManager.upsertDesignDocument`
`BucketManager.removeDesignDocument`	`ViewIndexManager.dropDesignDocument`
`BucketManager.publishDesignDocument`	`ViewIndexManager.publishDesignDocument`
`BucketManager.listN1qlIndexes`	`QueryIndexManager.getAllIndexes`
`BucketManager.createN1qlIndex`	`QueryIndexManager.createIndex`
`BucketManager.createN1qlPrimaryIndex`	`QueryIndexManager.createPrimaryIndex`
`BucketManager.dropN1qlIndex`	`QueryIndexManager.dropIndex`
`BucketManager.dropN1qlPrimaryIndex`	`QueryIndexManager.dropPrimaryIndex`
`BucketManager.buildN1qlDeferredIndexes`	`QueryIndexManager.buildDeferredIndexes`
`BucketManager.watchN1qlIndexes`	`QueryIndexManager.watchIndexes`

Reactive and Async APIs

The move to Java 8 as a baseline has opened the door to expose CompletableFuture in addition to a reactive API. You can now find it under the async() namespace of each level (for example, Cluster.async() → AsyncCluster). We also moved from RxJava to Reactor because it provides native Java 8 support and better performance out of the box. Reactor has a growing community, and integrates very well into the Spring ecosystem. The reactive API can now be found under the reactive() namespace (for example, Collection.reactive() → ReactiveCollection).

Like in SDK 2, the async and reactive APIs provide the same functionality as their blocking counterpart. There are only a couple places in the SDK where it does not make sense (such as the blocking datastructure APIs, which at the collection level implement the Java interfaces which do not have async or reactive counterparts).

if you need to use non-blocking APIs, we recommend using the reactive one. The async API based on CompletableFuture should only be used as a building block for higher level abstractions, or if you absolutely need the last drop of performance. The Flux and Mono types of reactor are very powerful and allow you to build efficient and flexible domain logic without blocking.

Since Reactor implements the reactive stream specification, you can still use RxJava through the interoperability interfaces. This is out of scope for the migration guide — please consult the reactor and rxjava documentations for further information.

As a starting point, the following types are comparable:

Table 8. SDK Reactor vs RxJava
SDK 2 RxJava	SDK 3 Reactor
`Observable<T>`	`Flux<T>`
`Single<T>`	`Mono<T>`
`Completable`	`Mono<Void>`

Configuration Options Reference

The following table provides commonly used configuration options in SDK 2 and where they can be now applied in SDK 3. Note that some options have been removed, and others have different ways to configure them.

Table 9. SDK 2.x vs SDK 3.x Environment Configs
SDK 2	SDK 3
`sslEnabled`	`SecurityConfig.enableTls`
`sslKeystoreFile`	on `CertificateAuthenticator`
`sslKeystorePassword`	on `CertificateAuthenticator`
`sslKeystore`	on `CertificateAuthenticator`
`sslTruststoreFile`	`SecurityConfig.trustCertificate`
`sslTruststorePassword`	`SecurityConfig.trustCertificate`
`sslTruststore`	`SecurityConfig.trustManagerFactory`
`bootstrapCarrierEnabled`	removed
`bootstrapHttpDirectPort`	via custom `SeedNode`
`bootstrapHttpSslPort`	via custom `SeedNode`
`bootstrapCarrierDirectPort`	via custom `SeedNode`
`bootstrapCarrierSslPort`	via custom `SeedNode`
`ioPoolSize`	via custom `IoEnvironment` pools
`computationPoolSize`	removed
`requestBufferSize`	removed
`responseBufferSize`	removed
`kvEndpoints`	`IoConfig.numKvConnections`
`viewEndpoints`	`IoConfig.maxHttpConnections`
`queryEndpoints`	`IoConfig.maxHttpConnections`
`searchEndpoints`	`IoConfig.maxHttpConnections`
`userAgent`	removed
`packageNameAndVersion`	removed
`observeIntervalDelay`	removed
`reconnectDelay`	removed
`retryDelay`	removed
`ioPool`	via custom `IoEnvironment` pools
`kvIoPool`	via custom `IoEnvironment` pools
`viewIoPool`	via custom `IoEnvironment` pools
`queryIoPool`	via custom `IoEnvironment` pools
`searchIoPool`	via custom `IoEnvironment` pools
`analyticsIoPool`	via custom `IoEnvironment` pools
`scheduler`	`scheduler`
`retryStrategy`	`retryStrategy`
`maxRequestLifetime`	removed
`keepAliveInterval`	removed
`autoreleaseAfter`	removed
`eventBus`	`eventBus`
`bufferPoolingEnabled`	removed
`tcpNodelayEnabled`	`IoConfig.enableTcpKeepAlives`
`mutationTokensEnabled`	`IoConfig.enableMutationTokens`
`runtimeMetricsCollectorConfig`	removed
`networkLatencyMetricsCollectorConfig`	removed
`defaultMetricsLoggingConsumer`	removed
`socketConnectTimeout`	removed
`callbacksOnIoPool`	removed
`requestBufferWaitStrategy`	removed
`memcachedHashingStrategy`	removed
`keyValueServiceConfig`	removed
`viewServiceConfig`	removed
`queryServiceConfig`	removed
`searchServiceConfig`	removed
`analyticsServiceConfig`	removed
`configPollInterval`	removed
`configPollFloorInterval`	removed
`certAuthEnabled`	on `CertificateAuthenticator`
`continuousKeepAliveEnabled`	removed
`keepAliveErrorThreshold`	removed
`keepAliveTimeout`	removed
`couchbaseCoreSendHook`	removed
`forceSaslPlain`	on `PasswordAuthenticator.allowedSaslMechanisms`
`operationTracingEnabled`	removed
`operationTracingServerDurationEnabled`	removed
`tracer`	`requestTracer`
`compressionMinSize`	`CompressionConfig.minSize`
`compressionMinRatio`	`CompressionConfig.minRatio`
`compressionEnabled`	`CompressionConfig.enable`
`orphanResponseReportingEnabled`	removed
`orphanResponseReporter`	removed
`networkResolution`	`IoConfig.networkResolution`
`managementTimeout`	`TimeoutConfig.managementTimeout`
`queryTimeout`	`TimeoutConfig.queryTimeout`
`kvTimeout`	`TimeoutConfig.kvTimeout`
`viewTimeout`	`TimeoutConfig.viewTimeout`
`searchTimeout`	`TimeoutConfig.searchTimeout`
`analyticsTimeout`	`TimeoutConfig.analyticsTimeout`
`connectTimeout`	`TimeoutConfig.connectTimeout`
`disconnectTimeout`	`TimeoutConfig.disconnectTimeout`
`dnsSrvEnabled`	`IoConfig.enableDnsSrv`
`cryptoManager`	removed
`propagateParentSpan`	removed

Comparing Older Documentation

You may want to visit documentation for older versions of the SDK, to help to understand application code that you are migrating. Versions that have reached end of life can be found in the archive. In the release notes pages of these older docs, you will also find links to the API reference for each no-longer-supported release.