Posts

Vitess Weekly Digest 11/12/18

We continue the digest from the Slack discussions for Sep 22 2018 to Oct 5 2018. We've fallen slightly behind on this, but will catch up again soon.

Enable VtGateExecute in vtctldArsalan [Sep 22nd] Hi, I want to query vitess on vtgate but I have below error. How can i fix this problem?
vitess@vtctldv3-hrl74:/$ vtctlclient -server 10.5.61.20:16999  VtGateExecute -server 10.5.61.21:16991 "show tables" E0923 05:14:55.169771    1102 main.go:61] Remote error: rpc error: code = Unknown desc = query commands are disabled (set the -enable_queries flag to enable)
sougou you need to add this flag to vtctld:  -enable_queries         if set, allows vtgate and vttablet queries. May have security implications, as the queries will be run from this process.
Multi-column Primary Key sjmudd [Sep 26th] Question: if a mysql table has a multi-column primary key, can Vitess handle this ? I vaguely remember the answer might be “no”. but looking in vschema_test.go I think that may not be the case.
sougou

Vitess Weekly Digest Sep 24, 2018

This week, we continue the digest from the Slack discussions for Sep 1 2018 to Sep 21 2018. As of this post, we are fully caught up on our backlogs.
Tracking progress of resharding
jk [Sep 5th] In the  SplitClone Stage of resharding, how can i get the percent of process ?  Or Could I estimate the time left ?
sougou I don't know of a formal way, but you can look at the database size. It should be a good indicator hopefully.
jk Alright. I'll check the mysql data size and compare. It is almost 400G in the source shard. So I'm not sure how long it will take. Thank you.
xuhaihua @jk just check the row size of the destination shard and the source shard in vtctld.
rnavarro [update] To "track" our progress we use this fancy log grep. It filters out a lot of the noise and shows us what we need to track some notion of progress:
kubectl logs --since=2m -f vtworker |grep -v 'not started' |grep -v 'copy done' |grep -v ' 0 threads' |grep -v 'Working on'…

Vitess Weekly Digest Sep 10, 2018

This week, we continue the digest from the Slack discussions for Aug 3 2018 to Aug 31 2018.
Secondary Vindexesraj.veerappan [Aug 3 9:27 AM] how do secondary vindexes work? would they result in further sharding?
weitzman [9:32 AM] If you have an authors table and a books table and you shard by author ID, a secondary vindex is a performance tool to help respond to the query, `select * from books where book_id = :id` Being sharded by authors, there’s not any obvious information in that query to help identify what the associated author ID / keyspace ID would be for the book entry (edited) A secondary vindex is a function that helps answer that question in a more effective way than just doing a scatter query across all shards
raj.veerappan [9:35 AM] ahh got it so sharding only happens by primary vindex and secondary vindexes help with routing to primary vindexes. Update streams like Maxellraj.veerappan [10:56 AM] I think I heard that Vitess lets you listen to a stream of db updates, similar t…

Vitess Weekly Digest Aug 24, 2018

This week, we continue the digest from the Slack discussions for Jul 25 2018 to Aug 2 2018 .
Update stream
Jian [Jul 25th at 1:27 PM] hi there, I'm new to Vitess, now I'm following the user-guide from vitess.io to explore vitess, in update stream section, I notice they have change log, where could I see these change logs so I can have a better understanding of the update stream?
sougou  That's the only documentation we have about the update stream, but we'll be fixing docs for all vitess very soon.
Jian  sure sure, thank you very much!
vamsi  @sougou even if documentation is not ready yet, is there some info you can provide to Jian about where he can see change logs?
sougou  The end to end test can actually be handy. Let me get the link.
sougou  https://github.com/vitessio/vitess/blob/master/test/update_stream.py
sougou  this section in particular https://github.com/vitessio/vitess/blob/master/test/update_stream.py#L222
Jian [1 day ago] :+1:
Fixing a failed MigrateServedTypesV…