- ABP Framework version: Any
- UI type: Any
- DB provider: EF Core
- Tiered (MVC) or Identity Server Separated (Angular): Any
I have previously reported this as a bug here. https://github.com/abpframework/abp/issues/9467
ABP EFCore migrations are currently running N+1 loops with the tenant seeding without recreating the dbContext instance for each loop. This is against microsoft's EFCore guidence and causes severe slowdowns after a few hundred tenants. I believe this is due to change tracking.
This seems fairly simple to fix but it's not something we can do here. Possible fixes are.
- Don't do long iterations. Pull out permissions etc. in one query. Looking at PermissionDataSeeder.cs this seems like a quick change.
- Recreate the dbContext object inside of the loop for each iteration ( each tenant )
- Turn off change tracking for the dbContext instance or specific queries.
The quick fixes seem to be disabling change tracking or recreating the dbContext on each tenant loop. I also think pulling out the permissions in bulk rather than one at a time would make a big difference.
For our number of users is it entirelly impossible to migrate the database seeding (structural changes are fast though.)
I submitted this to github and to bugs and issues and got no response, just closed as stale.
4 Answer(s)
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Hi,
I will check it out.
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Don't do long iterations. Pull out permissions etc. in one query. Looking at PermissionDataSeeder.cs this seems like a quick change.
I will try impove it, see https://github.com/abpframework/abp/pull/9978
Recreate the dbContext object inside of the loop for each iteration ( each tenant )
Database context instance is expensive, we should reuse
Turn off change tracking for the dbContext instance or specific queries.
Repository is abstract, you can do it in your project. see : https://github.com/abpframework/abp/issues/9652
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Thanks for your help with this!
Recreate the dbContext object inside of the loop for each iteration ( each tenant )
Database context instance is expensive, we should reuse
Are you sure about that? Maybe refresh after 500 tenants. Seeding tenants takes 300ms+ after the first few thousand. Opening dbContext should take <10ms.
I suggest creating a testdb with 20k tenants and running some tests on the migrator.
> Repository is abstract, you can do it in your project. see : https://github.com/abpframework/abp/issues/9652
Surely I can't disabled change tracking for ABP seed code though, not sure that would be safe even if I could. We do not yet have our own seeding.
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Hi,
I have test, you can try
SeedDataAsyncmethod in the<YourProjectName>DbMigrationServiceand replace it with the following code:private async Task SeedDataAsync(Tenant tenant = null) { Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed..."); using (var uow = _unitOfWorkManager.Begin(true, true)) { await _dataSeeder.SeedAsync(new DataSeedContext(tenant?.Id) .WithProperty(IdentityDataSeedContributor.AdminEmailPropertyName, IdentityDataSeedContributor.AdminEmailDefaultValue) .WithProperty(IdentityDataSeedContributor.AdminPasswordPropertyName, IdentityDataSeedContributor.AdminPasswordDefaultValue) ); await uow.CompleteAsync(); } }Markdown supported.Copy, paste, or drag & drop images and files (max 100 MB per file, 100 MB total per post)
