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https://issues.apache.org/jira/browse/IGNITE-5266?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17284143#comment-17284143
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Pavel Tupitsyn commented on IGNITE-5266:
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[~nathanchan2020] Ignite.NET has a LINQ provider that converts C# expressions
to Ignite SQL (similar to how Entity Framework does the same for SQL Server /
MySQL / Postgres).
In Ignite, I can write the following query:
{code}
var query = cache.AsCacheQueryable().Where(entry => entry.Value.Age > 20);
int count = query.Count();
{code}
As a result, the following SQL query will be executed:
{code}
select count (_T0.*) from Person as _T0
{code}
But what if the result of the query exceeds {{int.MaxValue}}? We'll get an
invalid result or an error.
That's why we need to add {{LongCount()}} support.
The first step is to add the following line to {{TestScalarQuery}} in
[CacheLinqTest.Misc|https://github.com/apache/ignite/blob/master/modules/platforms/dotnet/Apache.Ignite.Core.Tests/Cache/Query/Linq/CacheLinqTest.Misc.cs#L129-L128]
{code}
Assert.AreEqual(PersonCount, cache.LongCount());
{code}
Run this test and you'll get an error "Operator is not supported: LongCount()".
Try to fix this error by modifying
{{CacheQueryModelVisitor.ProcessResultOperatorsBegin}}.
Let me know if you have any questions.
> .NET: Support LongCount in LINQ
> -------------------------------
>
> Key: IGNITE-5266
> URL: https://issues.apache.org/jira/browse/IGNITE-5266
> Project: Ignite
> Issue Type: Improvement
> Components: platforms
> Reporter: Pavel Tupitsyn
> Assignee: Kin Chan
> Priority: Major
> Labels: .NET, LINQ, newbie
>
> H2 SQL {{COUNT}} function returns a {{long}}, but LINQ {{Count}} returns an
> int. We should simply add {{LongCount}} support the same way as {{Count}}.
> The tricky thing would be to test it.
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