How do I re-use the database connection pool that I already closed?

[voltrue2]

Hello,

I have an issue with the following operation, and I cannot seem to find anything related to this issue on online documentation anywhere.
Would you guys mind pointing me to the right direction?

Environment details

• OS: Mac OS high sierra
• Node.js version: v7.9.0
• npm version: v4.2.0
• @google-cloud/spanner version: v0.8.1

Steps to reproduce

1. Execute a select query
2. Close database by database.close()
3. Create new database by instance.database('myDatabase')
4. Execute another select query with the new database object
5. Error: pool is draining and cannot accept work

[callmehiphop]

@voltrue2 we have since swapped out pooling libraries and refactored a few other items. If possible, could you try upgrading to 1.0.x to see if that resolves your issue?

[voltrue2]

@callmehiphop
Thank you for the fast response.
I updated the version of my client to 1.0.3.
The error message changed to Database is closed.
I assume the way I am doing is not correct.
Here is the simplified version of my code that gives me the above error:

var spanner = Spanner({ projectId: myProjectId });
var instance = spanner.instance(myInstanceId);
var db = instance.database(myDatabaseName);
db.run({ sql: sql, params: params }, (error, results) => {
  // I can successfully run the query and I am closing db here.
  db.close();
  // I want to re-create/re-use db
  db.instance.database(myDatabaseName);
  db.run({ sql: sql2, params: params2 }, (error, results2) => {
    // here we have "Database is closed" error... 
  });
});

I am assuming that keeping a connection open is not really a good idea.

If you could point me to the right direction, I would really appreciate it.

Cheers!

[voltrue2]

@callmehiphop Any update on this question?

Cheers

[callmehiphop]

@voltrue2 I actually haven't been able to reproduce this, even when using your example. I have a hunch why and made a branch with a possible fix. Could you test against it to see if it resolves your issue?

[voltrue2]

@callmehiphop
OK I understand. Let me try and see if this makes any difference.

Cheers!

[voltrue2]

@callmehiphop I am still in the process of testing the new branch. (My apologies for taking long...)
I have a question, though.

When I lose all database connections on exit of the application process, I get this error in the callback of database.close(...):

1 session leak(s) found.

Also, I get this exception when I get this error: Unable to release unknown session.

I cannot seem to find the cause of the issue. Would you have some idea regarding this?

Cheers!

[vkedia]

You should make the database object just once per database and reuse. That will be much more peeformant.

…

On Wed, Feb 21, 2018, 9:06 PM Nobuyori Takahashi ***@***.***> wrote: @callmehiphop <https://github.com/callmehiphop> I am still in the process of testing the new branch. (My apologies for taking long...) I have a question, though. What would be the best practice to manage the connections? Should I be making the database object per database on starting of the process and re-use them? // we do this ONCE on starting of the processconst spanner = Spanner({ projectId: projectId });const instance = spanner.instance(instanceId);const databases = {};databases.myDb = instance.database('myDb');databases.hisDb = instance.database('hisDb');databases.herDb = instance.database('herDb');// we re-use these and close them on exit of the process...function onExitProcess() { databases.myDb.close(); databases.hisDb.close(); databases.herDb.close(); } Or should I be making the database instance every time we need a connection and close it when we are done? This is much slower for obvious reason of course... function readFromMyDb() { var spanner = Spanner({ projectId: projectId }); var instance = spanner.instance(instanceId); var db = instance.database('myDb'); db.run({ sql: 'xxxx', params: {...} }) .then(() => { // close the connection db.close(); }) .catch(...); } Cheers! — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#117 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ATdef4OKyayILhOZSBTORtOleWWArQ4Kks5tXPXugaJpZM4R_r_9> .

[voltrue2]

@vkedia
Thank you! Got it.
By the way, I was able to solve the issue that I initially had with the new branch @callmehiphop gave me.
But now I have this 1 session leak(s) found. error when I terminate the application process while reading and/or writing rapidly.
What I do on termination of the process is to call .close(...) on all database objects and wait for callbacks, and then terminate the process.
I was wondering if this is how you terminate all connections to Spanner properly?

Cheers

[callmehiphop]

@voltrue2 that error will have a messages attribute containing a call stack for each leak found. Usually it means a transaction was started but never finished. I would use the call stack to find the transaction in question to make sure that end() is being called for read only transactions and commit() is being called for read/write transactions.