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Single Row Protocol with SQLJRA Remote

IP.com Disclosure Number: IPCOM000103958D
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 107K

Publishing Venue

IBM

Related People

Brissette, LF: AUTHOR [+5]

Abstract

Remote Data Service is a set of functions for OS/2* Extended Edition (EE that allowed users to access databases not only on their local workstations but also on remote workstations. A private communication protocol (DRDA-0) was implemented in 1.3 EE to access relational database remotely. DRDA-0 is based on Distributed Relational Database Architecture* (DRDA) which is the architecture for connecting database products. DRDA basically makes use of an intermediate language defined in Distributed Data Management (DDM) architecture to pass information back and forth from client to server.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Single Row Protocol with SQLJRA Remote

      Remote Data Service is a set of functions for OS/2* Extended
Edition (EE that allowed users to access databases not only on their
local workstations but also on remote workstations.  A private
communication protocol (DRDA-0) was implemented in 1.3 EE to access
relational database remotely.  DRDA-0 is based on Distributed
Relational Database Architecture* (DRDA) which is the architecture
for connecting database products.  DRDA basically makes use of an
intermediate language defined in Distributed Data Management (DDM)
architecture to pass information back and forth from client to
server.

      A Single Row Protocol is architected in DRDA to produce the
desired effect needed to satisfy application SQL statements of DCL
CURSOR, followed by an OPEN of the cursor, and repeated FETCHes.  It
also accommodate the CLOSE of a cursor before or after all the rows
of the answer set has been fetched.  A number of DDM commands are
used in the Single Row Protocol.  Our performance result showed that
Single Row Protocol in DRDA-0 performed poorly in our homogeneous
environment (OS/2 EE client to OS/2 EE server).  The main reason for
the poor performance is because of the translation overhead from the
internal engine data structure to DDM commands and vice versa.

      Implementation of the Single Row Protocol takes advantage of
the fact that the data structures built on either the client or the
server in a homogeneous environment are the same.  Therefore the
underlying data structures are passed directly, without the
conversion step being necessary.

      The following is a discussion of the operations and functions
that the client and server performs:

1.  After the client and the server establish proper connection, an
    application may do an OPEN CURSOR request to the client.  The
    client will pass the SQLJRA (Request type = SQLJR_OPEN), input
    SQLDA and user input data to the server.  For Single Row
    Protocol, the client will set the third byte in SQLRFLAG (one of
    the SQLJRA triplets) to SQLCP_NO_BLOCK which indicating
    non-blocking request.

2.  The server receives and process the OPEN CURSOR request.  The
    server will place the DDS return code and SQLCA into the data
    stream.  The data stream is sent to the client.

3.  The client receives the DDS return code and SQLCA from the data
    stream and indicates to the application that open processing was
    successful.  If the client receives the SQLCA indicating an error
    occurring, it notifies the application of an error condition by
    passing the SQLCA to the application.

...