[ruby-oci8-devel] propose to implement pooling technology for Ruby-OCI8

[KUBO Takehiro]

Hi,

shiwei zhang <shiwei.zhang at oracle.com> writes:

>> BTW, I have a small question: you use "OCISessionBegin()" for 
>> T_EXPLICIT (external credential or OCI_SYSDBA, OCI_SYSOPER); and use 
>> "OCILogon" for T_IMPLICIT (OCI_CRED_RDBMS). *Why don't you use 
>> "OCISessionBegin()" for both T_EXPLICIT and  T_IMPLICIT?* I think 
>> "OCISessionBegin()" can work for both of the two conditions, do you 
>> have other concerns about this?

I agree in theory. I had used OCISessionBegin() for both before 0.1.13.
But I received a mail it sometimes causes a segmentation faults in 10
logons. Its environment was as follows.

  ruby 1.8.2
  ruby-oci8 0.1.13
  Oracle Client 8.1.7 (Windows)
  Oracle Server 8.0.5

This would be really rare. But there was no workaround. I changed to
use OCILogon for non-privilege logons.

If the code become too complex by your changes, you can merge them
to OCISessionBegin(). Because it might be caused by a bug in ruby-oci8
and its internal structure was changed. The same problem may not occur
in current implementation.

>> For now I think:
>>
>> # connection pool
>> pool = OCI8::ConnectionPool.new(username, password, tns_name, conn_min, conn_max, conn_incr)
>> conn = OCI8.new(pool, appusername, apppassword)
>> or
>> pool = OCI8::ConnectionPool.new(username, password, tns_name, conn_min, conn_max, conn_incr)
>> conn = OCI8.new($poolname, appusername, apppassword)
>>
>> # session pool
>> pool = OCI8::SessionPool.new(username, password, tns_name, sess_min, sess_max)
>> conn = OCI8.new(pool, appusername, apppassword)
>> or
>> pool = OCI8::SessionPool.new(username, password, tns_name, sess_min, sess_max)
>> conn = OCI8.new($poolname, appusername, apppassword)
>>
>> Notes:
>> username is used to create the pool, it's the implicit user. 
>> appusername is used to create/get a session from the pool. appusername 
>> could be different with username.

Another proposal:
  pool = OCI8::ConnectionPool.new(username, password, tns_name, conn_min, conn_max, conn_incr)
  conn = OCI8.new(appusername, apppassword, pool)

Change the current spec to:
  OCI8.new(username, password, dbname_or_pool = nil, privilege = nil)

Argument values username and password are appusername and apppassword
respectively if the third argument is a connection pool.

One question:
 Are appusername and apppassword required mandatory or optional?

>> $poolname is generate from "OCI8::ConnectionPool.new()" or 
>> "OCI8::ConnectionPool.new()". If we've gotten the value of $poolname, 
>> it's enough for "OCI8.new()" to create/hand out a session for appusername.

What is the data type of $poolname? If it is a string, we cannot
distinguish a logon with dbname from a login using connection pool.
If is is a connection pool object, when is the pool destroyed?

$poolname is set by a side effect of OCI::ConnectionPool.new(). IMO,
it is not straightforward.

-- 
KUBO Takehiro <kubo at jiubao.org>