About db:convert-type perfomance

I have 100Gb mysql db. Trying convertation to postgre, but it takes about forever.

Total 219283353 chunks, in first 30min about 200-400k done with ETA 2days, then it slow down and ETA became 20+ days. So no way to complete this. Traffic on VM ~50Kb\s.

Tried default chunk size and 100Mb with --chunk-size key.
Is it works as intended or more looks like bad perfomance\memory leak?

next 27, mariadb 10, postgre 15.


not sure if the following can help you, but if it is not foreclosed that postgresql settings could be the bottleneck

may have a look here

and here

don’t think so, PG is already tuned. Tested with single node and cluster installation.

have you seen this in the forum here?

That looks interesting, thanks.
3rd party migration probably my only way, since i’m not only one have problems with occ perfomance.

The --chunk-size option expects an integer value. It defaults to 1000 but you might try 10000. If you specified 100Mb I think it would have been cast to 100 further slowing things slow (I would expect anyhow).

What does the CPU or Disk I/O utilization look like on the app server and the db servers?

hm, i found somewhere that --chunk-size can be 1-100 with default 10.

Any resources utilization is about zero.

I’m looking at the code. :slight_smile: It defaults to 1000:

You might be mixing up the term “chunk size” with the one used for WebDAV file transfers. That’s completely unrelated.

Across all servers involved? Can you provide output from htop and/or at least the process statuses from a ps?

That only one key that required for this method and not exist at official doc)

Tested with chunk size 10000.
Before calculation of oc_filecache table, with default size i wait for about 5min. Now it takes about 20min.
First time failed by timeout, 2nd started.

Looks much better, but still very slow. Also process a bit slow down after first million.

 - oc_filecache
chunked query, 21929 chunks
   2370000/219283353 [>---------------------------]   1% 47 mins/3 days

Utilization also not high.

old db

new db

old db

new db

postgre process often go to idle status, between chunks.