Scavenging does not work

EventStoreDB
#1

Hi,

I’m using Event Store 3.0.0 RC2 from the website.

I cannot scavenge my database. When I click ‘Scavenge’ in the web interface the following message appears in the log:

[03348,12,14:46:38.446] SLOW BUS MSG [MainBus]: ScavengeDatabase - 109ms. Handle

r: StorageScavenger.

[03348,12,14:46:38.446] SLOW QUEUE MSG [MainQueue]: ScavengeDatabase - 110ms. Q:

0/0.

[03348,29,14:46:40.704] SCAVENGING: started scavenging of DB. Chunks count at st

art: 40. Options: alwaysKeepScavenged = False, mergeChunks = True

[03348,29,14:46:41.097] SCAVENGING: started to scavenge & merge chunks: #0-15 (c

hunk-000000.000002)

Resulting temp chunk file: c86c8b72-4a65-45f4-a89a-4e2b3063bf2d.scavenge.tmp.

[03348,29,14:46:41.707] SCAVENGING: error while scavenging DB.

An item with the same key has already been added.

How can I resolve this problem?

Thanks.

  • Morten.
#2

What flags did you start with? Is this a database that you have upgraded from a previous version?

#3

Can you try disabling merge chunks on the options?

#4

Hi James,

We start it with:

#5

The option to disable merging is:

DisableScavengeMerge

This obviously follows the patterns for commandline/js/etc so --disable-scavenger-merge if that works maybe we can grab the chunks in question to look through whats happening?

Greg

#6

Hi Greg,

Is it possible to send this command (DisableScavengeMerge) to the server without restarting it? If so, how?

  • Morten.
#7

No its command line/config file. We have been discussing the ability to make some of these config changes on the fly though.

#8

I now tried restarting the server with --nomerge, but that just gives me some other error:

[02108,05,14:49:37.890] SCAVENGING: started scavenging of DB. Chunks count at start: 1. Options: alwaysKeepScavenged = False, mergeChunks = False

[02108,05,14:49:37.890] SCAVENGING: stopping scavenging pass due to non-completed TFChunk for position 0.

[02108,05,14:49:37.890] SCAVENGING: initial pass completed in 00:00:00.0001280.

[02108,05,14:49:37.890] SCAVENGING: total time taken: 00:00:00.0001906, total space saved: 0.

What to do?

  • Morten.
#9

That says there is only one chunk and you cant scavenge a currently ongoing chunk (so its work is done) its not an error

#10

Hi Greg,

But that cannot be the case, I have 25 files named chunk-* all with a fixed size 262,135 KB. Shouldn’t I be able to clear up some space using scavenging?

#11

Ignore my last message. It was the wrong db. On the correct db, this error occurs:

[02780,33,10:39:53.796] SCAVENGING: started scavenging of DB. Chunks count at start: 41. Options: alwaysKeepScavenged = False, mergeChunks = False

[02780,33,10:39:53.886] SCAVENGING: started to scavenge & merge chunks: #0-15 (chunk-000000.000002)

Resulting temp chunk file: faeeeefd-7f82-4605-9906-39f33711c35a.scavenge.tmp.

[02780,33,10:39:54.194] SCAVENGING: error while scavenging DB.

An item with the same key has already been added.

And yes, it was started with --nomerge, which I can see from the log:

DISABLE SCAVENGE MERGING: True (–nomerge from command line)

#12

Is it possible to send your database? If not I will add a significant amount of logging code and see if you can run it there.

#13

It’s not possible to send the database.

Thanks!

#14

Have you built from source before or are you strictly a binary user? I am going to instrument the code with a bunch of logging that you can run locally. Is it possible that you can build from sources to run it?

#15

Any feedback on this Morten?

#16

did this ever get resolved. Struggling with an Rc2 installation (yes,yes, Should have updated…) that I can’t scavenge (throws same error as described in this thread). GBs are stacking up

-Vidar

#17

Long ago.

#18

Rephrase: Any way to solve this without updating? Tried a test update some time ago and found that clients using .net lib stopped working, so was hoping to find a solution without updating. (or at least update to a version compat with 3.0rc2 clients)

(And yes I know I’m to blaim, but the current setup was supposed to be temporary…)

-Vidar

#19

Hmm I would have to research that. I am not sure what changes were
involved. Also I am unsure of what client changes there may have been
I am 99% sure that a 3.0.0 client should still work with 3.6.2 (there
have only been additive changes that I know of hence the versioning)
from 3.0.0RC2 I am not positive.

#20

ok, thanx for responding.

-Vidar