Is there any built-in API which provides a pagination feature in Pivotal GemFire, such as in the QueryService API or using Functions? We are currently using Pivotal GemFire 9.3.0 running in PCC.
TIA.
No yet. It is a planned feature for SD Lovelace/Moore release trains. See SGF-524 - Add support for PagingAndSortingRepositories. NOTE: sorting is already supported; paging is a WIP.
There is not. However there is a common pattern for this. Instead of directly querying the matching objects, write your query to return the keys of the matching objects. The client can then implement paging (e.g. page1 is key0-key99, page 2 is key 100-199, etc.). Use the "getAll" method with a list of keys to pull back one page at a time.
BTW, you can query the keys like this: "select key from /person.entries where value.ssn='222-22-2222'"
Related
I have recently upgraded application from Elastic search 5.3.1 to 6.0.
My requirement was to get all the indices which were associated with specific alias.
I used below mentioned snippet to fetch all indices associated with specific alias . This snippet is working fine in 5.3.1 and giving only those indices which are associated with that specific alias.
GetAliasesResponse r = client.admin().indices().getAliases(new
GetAliasesRequest("givenalias")).actionGet();
But after ES 6.0 , the same snippet giving all the indices which are created in system .
Ideally it should only return those indices which are associated with given alias .Not others. This was working in Elastic search 5.3.1.
TL;DR: It is an intended breaking change in the Java API of Elasticsearch (though it is not explicitly mentioned in the "Breaking changes in 6.0 ยป Java API changes" page).
The following is the story of discovering this fact. (Note: the original answer was heavily edited, hence comments might be out of date.)
Breaking changes in the REST API in 6.0
First I noticed that this part of the REST API changed in Elasticsearch 6.0. There are two reported breaking changes concerning aliases:
GET /_aliases,_mappings syntax was removed in favor of GET /_aliases/GET /_mappings
Indices aliases api resolves indices expressions only against indices
Though there isn't mentioned anything concerning OP's case.
From what I have seen doing queries, this query works in Elasticsearch 5:
GET /alias1/_aliases
And does not work in Elasticsearch 6, giving the following error:
{
"error": "Incorrect HTTP method for uri [/alias1/_aliases] and method [GET], allowed: [PUT]",
"status": 405
}
Interestingly, GET /alias1/_alias works in both versions and returns same result.
Moreover, I didn't manage to find an example of GET /alias1/_aliases in the documentation of nor 5.6, neither 6.0.
Reproducing the bug
After having realised that OP is actually using the Java API, I managed to reproduce the exact same behavior.
The following code:
GetAliasesResponse alias1 = client.admin().indices()
.getAliases(new GetAliasesRequest("alias1")).actionGet();
In ES 5 produces this in the IntelliJ debugger:
And for ES 6 I've got the following:
As you can see, there are extra keys in the second output, which have empty values.
Diving into the source code
Quick search over the elasticsearch codebase gave me the final explanation. In ES 5 there was a test testIndicesGetAliases which was checking that list of indices returned for a test alias has exactly one element (IndexAliasesIT.java#L554):
logger.info("--> getting alias1");
GetAliasesResponse getResponse = admin().indices().prepareGetAliases("alias1").get();
assertThat(getResponse, notNullValue());
assertThat(getResponse.getAliases().size(), equalTo(1));
And in 6.0 it checks that the size is 5! (IndexAliasesIT.java#L573)
logger.info("--> getting alias1");
GetAliasesResponse getResponse = admin().indices().prepareGetAliases("alias1").get();
assertThat(getResponse, notNullValue());
assertThat(getResponse.getAliases().size(), equalTo(5));
This change was introduced in this commit, which is related to these issues:
Remove comma-separated feature parsing for GetIndicesAction #24723
_alias API no longer accepts index wildcards #25090
This is actually interesting, because one of the reported REST API breaking changes that we have see above also broke compatibility of some Java API calls.
What you can do
In short term, you need just to filter out those keys with empty values.
In longer term I think it makes sense to migrate to Java High Level REST Client since Elastic plan to deprecate the TransportClient in version 7.0:
We plan on deprecating the TransportClient in Elasticsearch 7.0 and
removing it completely in 8.0. Instead, you should be using the Java
High Level REST Client, which executes HTTP requests rather than
serialized Java requests.
In general, Elasticsearch breaks compatibility quite often, so it's better to stay away from the dark corners of it like Java API.
Thanks for reading.
Hope that helps!
I want to use SDN4.0 to visualize by D3 in web application.For example,I want to use the following cypher query to get data:
#Query("MATCH (n:app)-[r:r1]->(m:app) RETURN n.alias,r,m.alias")
Iterable<Map<String, Object>> getAllRelations();
But the httpServer not response the exact data I want.
[{n.alias=A, r=(227)-[r1]->(235), m.alias=B}, ....]
And I want to response r1's properties ,tried r1.* but failed.
From the http://neo4j.com/developer/guide-data-visualization/ there is possible to set resultDataContents to graph(origin as rest)
So Is it any possiblity to set this parameter in SDN4.0 or have other solutions?
Thanks if having any ideas.
SDN is for creating domain rich applications. As such it's not the best tool to use if all you need is a list of properties to represent a graph.
You have a couple of paths as I can see it:
Model your application properly with SDN. Use #NodeEntity on a class called App and create a #Relationship to another App. You can then leverage SDN's repositories to return you a rich domain model which you can then transform (e.g. using DTO's) to the front end if need be.
Use the java Neo4j client, OGM HTTP driver (Undocumented), or if you are happy to completely use Javascript (either from the browser or with meteor or using a NodeJS server) you can just use the Javascript driver and call the database directly.
Either way if you are using D3 I highly recommend you use JSOG to represent your model in the front end.
How do I query for relationship data in spring data neo4j 4?
Above Answer solved my question.By using Neo4jOperations.queryForObjects() under Spring data Neo4j and return path in cypher query.
I am looking for a good example to lock a document in elastic search. The below link explain how to do this in elasticsearch.
http://www.elasticsearch.org/guide/en/elasticsearch/guide/current/concurrency-solutions.html
How can i achieve this using NEST. can someone suggest an approach to start with.
To start with, read the NEST Quick Start article. In particular, note the following:
NEST is a high level elasticsearch client that still maps very closely to the original elasticsearch API. Requests and Responses have been mapped to CLR objects and NEST also comes with a powerful strongly typed query dsl.
Consider also, that you may not require the added level of abstraction that NEST provides, and may prefer to directly utilise Elasticsearch.NET. Read also, it's own Quick Start article.
With that in mind, implementing the steps in the Solving concurrency issues article using NEST / Elasticsearch.NET is simply a matter of identifying the .NET methods that correspond to the necessary Elasticsearch API methods. The first one for example:
PUT /fs/lock/global/_create
{}
In NEST would look something like:
var createGlobalLockResponse = esClient.Index<object>(new object(), f => f
.Index("fs")
.Type("lock")
.Id("global")
.OpType(global::Elasticsearch.Net.OpType.Create));
Regarding the check of whether "this create request fails with a conflict exception", check the properties on the createGlobalLockResponse object. In particular, Created and if you're intending to get a bit more specific in the handling, ServerError.
Is there a way to
create a fulltext-index with a given lucene-analyzer on a certain node-Type (and certain fields only)
to get this index updated automatically when a node of the given type is created / deleted
query this index over the Cypher- oder the REST-API
I am using the Cypher/REST-Interface (and of course the shell, etc.) of the server not the embedded version.
If this is not available (which I guess): Is something like this on the roadmap?
Thank you in advance!
Short answer: no
Little bit longer answer:
You can write a KernelExtension adding a TransactionEventHandler that amends the fields to be fulltext indexed to a manual index (aka legacy index).
The code should be wrapped into an unmanaged extension and deployed to the server.
There something similar implemented within https://github.com/sarmbruster/neo4j-uuid.
The contents of the legacy index can be accessed using start n=node:myindex('lucene query string') in Cypher
Implementing a sort in my query, how can I set IgnoreUnmapped(true) when using NEST API?
The default value is false, which means if the field doesn't exist it won't return any results, using NEST how to change the default value?
And is there any option when sorting with NEST to be able to sort with raw query? like FilterRaw()? SortRaw()?
This was blatantly missing in the API I just pushed support and tests for this:
https://github.com/Mpdreamz/NEST/commit/e92378589e0afaa9f6559507deb02c858d2c554d
This should make it into the next release (for future googlers next release meaning a release after 0.11.1.0).