private void PageEntities <TEntity>(
SmartObjectContext context,
DbSet <MediaStorage> mediaStorages,
IOrderedQueryable <TEntity> query,
Action <TEntity> moveEntity) where TEntity : BaseEntity, IHasMedia
{
var pageIndex = 0;
IPagedList <TEntity> entities = null;
do
{
if (entities != null)
{
// detach all entities from previous page to save memory
context.DetachAll(false);
entities.Clear();
entities = null;
}
// load max 1000 entities at once
entities = new PagedList <TEntity>(query, pageIndex++, PAGE_SIZE);
entities.Each(x => moveEntity(x));
// save the current batch to database
context.SaveChanges();
}while (entities.HasNextPage);
}
protected virtual void PageEntities <TEntity>(IOrderedQueryable <TEntity> query, Action <TEntity> moveEntity) where TEntity : BaseEntity, IHasMedia
{
var pageIndex = 0;
IPagedList <TEntity> entities = null;
do
{
if (entities != null)
{
// detach all entities from previous page to save memory
_services.DbContext.DetachEntities(entities);
entities.Clear();
entities = null;
}
// load max 100 entities at once
entities = new PagedList <TEntity>(query, pageIndex++, PAGE_SIZE);
entities.Each(x => moveEntity(x));
// save the current batch to database
_services.DbContext.SaveChanges();
}while (entities.HasNextPage);
}
protected int MovePictures(bool toDb)
{
// long running operation, therefore some code chunks are redundant here in order to boost performance
// a list of ALL file paths that were either deleted or created
var affectedFiles = new List <string>(1000);
var ctx = _pictureRepository.Context;
var failed = false;
int i = 0;
using (var scope = new DbContextScope(ctx: ctx, autoDetectChanges: false, proxyCreation: false, validateOnSave: false, autoCommit: false))
{
using (var tx = ctx.BeginTransaction())
{
// we are about to process data in chunks but want to commit ALL at once when ALL chunks have been processed successfully.
try
{
int pageIndex = 0;
IPagedList <Picture> pictures = null;
do
{
if (pictures != null)
{
// detach all entities from previous page to save memory
ctx.DetachEntities(pictures);
// breathe
pictures.Clear();
pictures = null;
}
// load max 500 picture entities at once
pictures = this.GetPictures(pageIndex, 500);
pageIndex++;
foreach (var picture in pictures)
{
string filePath = null;
if (!toDb)
{
if (picture.PictureBinary != null && picture.PictureBinary.Length > 0)
{
// save picture as file
SavePictureInFile(picture.Id, picture.PictureBinary, picture.MimeType, out filePath);
}
// remove picture binary from DB
picture.PictureBinary = new byte[0];
}
else
{
// load picture binary from file and set in DB
var picBinary = LoadPictureFromFile(picture.Id, picture.MimeType, out filePath);
if (picBinary.Length > 0)
{
picture.PictureBinary = picBinary;
}
}
// remember file path: we must be able to rollback IO operations on transaction failure
if (filePath.HasValue())
{
affectedFiles.Add(filePath);
//picture.IsNew = true;
}
// explicitly attach modified entity to context, because we disabled AutoCommit
picture.UpdatedOnUtc = DateTime.UtcNow;
_pictureRepository.Update(picture);
i++;
}
// save the current batch to DB
ctx.SaveChanges();
} while (pictures.HasNextPage);
// FIRE!
tx.Commit();
}
catch (Exception ex)
{
failed = true;
tx.Rollback();
_settingService.SetSetting <bool>("Media.Images.StoreInDB", !toDb);
_notifier.Error(ex.Message);
_logger.Error(ex);
}
}
}
if (affectedFiles.Count > 0)
{
if ((toDb && !failed) || (!toDb && failed))
{
// FS > DB sucessful OR DB > FS failed: delete all physical files
// run a background task for the deletion of files (fire & forget)
Task.Factory.StartNew(state =>
{
var files = state as string[];
foreach (var path in files)
{
if (File.Exists(path))
{
File.Delete(path);
}
}
}, affectedFiles.ToArray()).ConfigureAwait(false);
}
// shrink database (only when DB > FS and success)
if (!toDb && !failed)
{
ctx.ShrinkDatabase();
}
}
return(i);
}