Duplicate ID's on database #9638

Ricavir created 3 years ago

Prerequisites

Angular
.net core

If issue related with ABP Framework

5.7.0

I've created a manager class on server side to generate ID's without same values. You'll find the code below :

[UnitOfWork(IsolationLevel.ReadUncommitted)]
        public virtual async Task GenerateSuccessiveId(Event eventToManage)
        {
            using (_unitOfWorkManager.Current.DisableFilter(AbpDataFilters.SoftDelete))
                eventToManage.SuccessiveId = (await _eventRepository.GetAll().Where(ev=>ev.TenantId == eventToManage.TenantId).MaxAsync(s => s.SuccessiveId)) + 1;

            long nextEventId = await SettingManager.GetSettingValueForTenantAsync<long>(AppSettings.TenantSuccessiveId.NextEventId, eventToManage.TenantId);
            if (eventToManage.SuccessiveId < nextEventId)
                eventToManage.SuccessiveId = nextEventId;
        }

This has been working great for the last 2 years. But I had a case recently where 3 requests came in a very short time to the server. It results in the following behavior :

First request : SuccessiveId = 932 --> OK
Second request : SuccessiveId = 933 --> OK
Third request : SuccessiveId = 933 --> NOK

Do you see any mistake in this code block ?

3 Answer(s)

0

ismcagdas created 3 years ago
Support Team

Hi,

If you want below code to generate unique numbers;

(await _eventRepository.GetAll().Where(ev=>ev.TenantId == eventToManage.TenantId).MaxAsync(s => s.SuccessiveId)) + 1;

You need to use lock in generation of this code. It must be thread safe.
0

Ricavir created 3 years ago

Hi @ismcagdas,

I will try to convert to a thread less method and add a lock. Thanks
0

ismcagdas created 3 years ago
Support Team

Hi @ricavir

Thanks. Please reopen if you can't solve this problem and share your final code.

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