Ravendb select - update multiple row - ravendb

Question

I am trying to select and update multiple row from ravendb, but it recursively update same rows. Namely first 100 rows. There is no changes.
Here is my code. How can I select some rows, Update some fields of each rows and do it again and again until my job finished.
var currentEmailId = 100;
using (var session = store.OpenSession())
{
var goon = true;
while(goon){
var contacts = session.Query<Contacts>().Where(f => f.LastEmailId < currentEmailId).Take(100);
if(contacts.Any()){
foreach(var contact in contacts){
EmailOperation.Send(contact, currentEmailId);
contact.LastEmailId = currentEmailId;
}
session.SaveChanges();
}
else{
goon = false
}
}
}

Answer 1

It's probably because you're doing a query immediately after saving changes, without letting the indexes update after save changes. Thus, you're getting back the same items. To fix that, you can tell SaveChanges to wait until indexes are updated. Your code would look something like this:
Try this:
var goon = true;
var currentEmailId = 100;
while (goon)
{
using (var session = store.OpenSession())
{
var contacts = session.Query<Contacts>()
.Where(f => f.LastEmailId < currentEmailId)
.Take(100);
if(contacts.Any())
{
foreach(var contact in contacts)
{
EmailOperation.Send(contact, currentEmailId);
contact.LastEmailId = currentEmailId;
}
// Wait for the indexes to update when calling SaveChanges.
DbSession.Advanced.WaitForIndexesAfterSaveChanges(TimeSpan.FromSeconds(30), false);
session.SaveChanges();
}
else
{
goon = false
}
}
}
If you're updating many contacts at once, you may wish to consider using using Streaming query results combined with BulkInsert to update many Contacts en mass.