On Monday, August 27, 2012 1:51:15 PM UTC-7, Jeremy Evans wrote:
>
> On Monday, August 27, 2012 1:28:34 PM UTC-7, Ravi wrote:
>>
>> I think increasing the number of max_connection solved the isseue. I did
>> not see any more "Too many connections" errors since past three days.
>>
>
> Good.
>
>
>> Few more question: When I open a connection to db, does the connection
>> close automatically. How the connection is handled by Sequel and what is
>> its scope?
>>
>
> The connection stays open until:
>
> 1) A disconnect is detected on it.
> 2) The connection is disconnected manually via Database#disconnect.
>
>
>> eg:
>> I have a following class dbConnect to connect to db:
>>
>> class dbConnect
>> def initialize
>> @db = Sequel.connect("myswl:...", :max_connection=>3,
>> :pool_sleep_time=>0.01, :pool_timeout=>30)
>> end
>> def execute_query
>> #perform some query here
>> end
>> end
>> Can I define a function to close this particular (@db) connection or it
>> will be handled by Sequel??
>>
>
> That's not a connection, that's a Database object (which has a pool of
> connections). If you really want a separate Database object and connection
> pool just to execute one query, you can pass a block to Sequel.connect:
>
> Sequel.connect("myswl:...", :max_connection=>3, :pool_sleep_time=>0.01,
> :pool_timeout=>30) do |db|
> # ...
> end
>
> That's not generally a good idea, though.
>
>
>>
>> Now, in another file:
>>
>> def db_perform
>> db = dbConnect.new
>> db.exec_query
>> end
>> db_perform
>>
>> Scope of this connection? Does the db connection automatically close at
>> the end of the above function (db_perform)?
>>
>
> No, connections will remain in the connection pool so that they can be
> used by other threads. If you really want to control the scope of
> connections, use the master branch, set :connection_handling=>:disconnect,
> and use Database#synchronize to manually control the scope of each
> connection.
>
ok, I think I am doing lot of "bad" things here ( may be because I started
using Sequel a few days back)
What I exactly want to do (may not be a good method to do)
I want to perform 2-3 basic db operation:
So created a class dbConnect as I specified earlier:
class dbConnect
def initialize(table_name)
@DB = Sequel.connect("myswl:...", :max_connection=>3,
:pool_sleep_time=>0.01, :pool_timeout=>30)
@dataset = @DB[table_name]
end
def add(parameters)
#perform insert query here @dataset.insert(parametrs)
end
#similarly update and fetch
end
I have other program which is multi-threaded and each thread (not a db
thread) calls this class and perform certain query at the same time as
follows:
#for each thread in the code
db = dbConnect.new(:test_table)
db.add(list_of_param)
db.update(list_of_param)
####
Thats it.
What action I can take now with what I understood is:
Making the connection as SingleThreaded (or max_connection=>1) and
disconnecting the database.
class dbConnect
def initialize(table_name)
@DB = Sequel.connect("myswl:...")
Sequel.single_threaded = true
@dataset = @DB[table_name]
end
def disconnect
@DB.disconnect #here I dont need synchronize if the connection is
Single threaded..
end
end
db = dbConnect.new(:test_table)
db.add(list_of_param)
db.update(list_of_param)
db.disconnect
I know it is not optimal (it is just a working code!). I really appreciate
if you can correct or optimize it.
Thanks,
Ravi
>
> Jeremy
>
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