Greedy lock on the migrations table

[gvko]

Does Umzug or Sequelize do a lock on the migrations table (the table in which the executed migrations are stored, f.e. SequelizeMeta) before the migrations are to be executed and until they are finished?

If so, is it a greedy (no read/write possibilities) or a lazy lock?

I went through both the Umzug and Sequelize Migrations documentation and could not find information about that.

[jukkah]

No, currently it's not locking the table at all.

[caseyduquettesc]

Would help with #59

[jaulz]

Any chance to implement it? Are you willing to accept a PR?

[atorma]

I've used this: https://github.com/SGrondin/umzug-sync

[mmkal]

Paging @gvko @jukkah @caseyduquettesc @jaulz @atorma @SGrondin on this (three-year-) old issue! Do you still use umzug? Would you still be interested in a built-in locking feature? If so, are there any existing solutions you could share to use as inspiration/for feature discovery? Is umzug-sync still a good starting point for building something more general/database-agnostic?

Edit: also paging the 👍 ers - @DanielHreben, @ningshen, @bogdan, @pmoleri, and @ghohmann-asapp

[gvko]

@mmkal , yeah, I can wait even a few weeks. I'm not in a hurry. 😆

I'm using the sequelize instance, but executing a raw SQL query in order to acquire/release the lock.
I'll create it in a separate repo of mine this weekend and I'll link it here.
Cuz currently it's not usable standalone. It's tightly integrated with the project I'm using it in rn, so I gotta make it more generic. 👍

[bmxpiku]

I actually used this adjusted version of this https://github.com/DanielHreben/sequelize-migration-lock/blob/master/index.js
which works pretty well with AWS feature where instance while provisioning new updated ones, gets a little bit delayed, so it's just enough time to roll out a migration.

[EdwardIII]

@gvko Is this where you implemented your locking solution? https://github.com/gvko/feathers-migrations

[gvko]

@EdwardIII , no, I haven't made it public yet. I kinda' forgot about this thread. I'll be looking into this in the following weekend(s) and update here. :)

[EdwardIII]

@gvko that would be amazing! We're upgrading to sequelize 6, which somehow causes umzug-sync to break with these errors (pasted below). the migrations run fine themselves with just umzug, it's just with umzug-sync they're bust.

Any chance of a sneaky gist preview (if the main work is being done in a single file that can easily be pasted into a gist?)

Executing (c443e1b5-38a6-4c3b-8a44-3df01ac338b1): START TRANSACTION;
Executing (c443e1b5-38a6-4c3b-8a44-3df01ac338b1): SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
Executing (c443e1b5-38a6-4c3b-8a44-3df01ac338b1): ROLLBACK;
(node:35) UnhandledPromiseRejectionWarning: Error: rollback has been called on this transaction(c443e1b5-38a6-4c3b-8a44-3df01ac338b1), you can no longer use it. (The rejected query is attached as the 'sql' property of this error)
    at checkTransaction (/usr/src/app/server/node_modules/sequelize/lib/sequelize.js:598:23)
    at /usr/src/app/server/node_modules/sequelize/lib/sequelize.js:618:9
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
    at emitUnhandledRejectionWarning (internal/process/promises.js:168:15)
    at processPromiseRejections (internal/process/promises.js:247:11)
    at processTicksAndRejections (internal/process/task_queues.js:96:32)
(node:35) Error: rollback has been called on this transaction(c443e1b5-38a6-4c3b-8a44-3df01ac338b1), you can no longer use it. (The rejected query is attached as the 'sql' property of this error)
    at checkTransaction (/usr/src/app/server/node_modules/sequelize/lib/sequelize.js:598:23)
    at /usr/src/app/server/node_modules/sequelize/lib/sequelize.js:618:9
    at processTicksAndRejections (internal/process/task_queues.js:95:5)

[SamSpiri]

Hi, dear @gvko bless you. Please show what you have on the topic. "Just do it."

[gvko]

Alright, guys, finally it's here: db-migrator-distributed. For the lack of a better name, that's what I chose... :D

Enjoy, give feedback and contribute! 🙌
cc @SamSpiri @EdwardIII @mmkal @jaulz

[SamSpiri]

This is awesome! Will try, thanks in advance.

[SamSpiri]

Should this be mentioned in the upstream docs probably? ;)

[gvko]

My pleasure! 🙌
Any feedback and contributions are more than welcome!

[EdwardIII]

Interesting @gvko we ended up going for an approach similar to the one you originally linked to. Cool to see your implementation!