Name resolution method for a distributed data base management system

• US 5,357,630 A
• Filed: 10/21/1991
• Issued: 10/18/1994
• Est. Priority Date: 10/21/1991
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Oprescu, Valentin, Dalmia, Manoj
• Primary Examiner(s): Heckler, Thomas M.
• Application Number:
  US07/780,182
• Time in Patent Office: 1,093 Days
• Field of Search: 395/600, 364/DIG. 1
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2228 Indexing structures
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor

Abstract

At start-up, input/output bus is scanned to detect any unprocessed I/O devices and each device is scanned to locate any unprocessed data base partitions. If any are located, these partitions are stored in memory and the partitions are marked as processed. During run-time, a message is received indicating that a new I/O device has come on-line. The new I/O device is scanned for any unprocessed partitions. The information regarding the partitions is stored in memory and the partition is marked as processed. The process also functions during data base operations to make connections between a client and a data base. A sequential process routes a connection request message through one node at a time around the network until all of the tables requested have been connected. If the message is returned to the originating node with out being completed, a failure is reported to the client. A parallel process broadcasts the connection request message to all of the nodes on the network simultaneously. Each node will then make local connections with any requested tables residing on that node and reply to the originating node. Once all of the replies are received, the originating node will collate the replies and assign tables to the client. In the event of duplicate table names, the rejected ones will be issued a disconnect.

Claims

1. In a distributed data base management system, a method for performing name resolution during a start-up operation of said system, said method comprising the steps of:

(a) scanning an input/output bus for an unprocessed input/output device, the unprocessed input/output device being defined as an input/output device with respect to which steps (c) through (f) have not yet been performed;

(b) exiting said method if said unprocessed input/output device is not found;

(c) scanning said unprocessed input/output device for an unprocessed data base partition of a data base, the unprocessed data base partition being defined as a data base partition with respect to which steps (d) through (f) have not yet been performed, said data base partition having an information regarding said data base, the information of said data base identifying one or more data sets within the data base;

(d) marking said unprocessed input/output device as processed if said unprocessed data base partition is not found in step (c);

(e) outputting a name of said data base partition and returning to step (c) if a name of said data base is not unique; and

(f) loading said information of said data base into a memory and returning to step (c) if said name of said data base is unique.

2. The method of claim 1 wherein said information regarding said data base is a name of said data base.

3. The method of claim 1, further comprising the steps of:

scanning the memory of said system for said information of said data base residing on a processed input/output device during a run time operation of said system when the input/output device is taken off-line; and

discarding said information from said memory.

4. In a distributed data base management system, a method for performing name resolution during a run-time operation of said system, said method comprising the steps of:

(a) receiving a message that an input/output device is on-line;

(b) scanning said input/output device for an unprocessed data base partition of a data base, the unprocessed data base partition being defined as a database partition with respect to which steps (d) through (f) have not yet been performed, said data base partition having an information regarding said data base, the information of said data base identifying one or more data sets within the data base;

(c) exiting said method if said unprocessed data base partition is not found in said input/output device;

(d) marking said unprocessed input/output device as processed if said unprocessed data base partition is not found in step (b);

(e) outputting a name of said data base partition and returning to step (b) if a name of said data base is not unique; and

(f) loading said information of said data base into a memory and returning to step (b) if said name of said data base is unique.

5. The method of claim 4 wherein said information regarding said data base is a name of said data base.

6. In a distributed data base management system, a method for fulfilling a data base connection request issued by a client comprising the steps of:

receiving a connection request method at a first node, said connection request message requesting connection to a plurality of table names;

connecting a table, located on said first node and having a first table name of said plurality of table names, to said client if said connection request message was not previously received by said first node and said first table exists on said first node;

marking said first table name on said connection request message as being connected following said step of connecting;

forwarding said connection request message to a second node if a second table name of said plurality of table names is not marked as being connected and repeating said method with the second node becoming the first node;

sending a completion reply to said client if said plurality of table names are all marked as being connected; and

sending a failure reply to said client if said connection request message was previously received by said first node.

7. In a distributed data base management system, a method for fulfilling a connection request message issued by a client comprising the steps of:

(a) receiving said connection request message at a first node, said connection request message requesting connection to a table having a table name;

(b) building a list of a plurality of nodes on a network coupled to said first node;

(c) broadcasting said connection request message from said first node to said plurality of nodes on said network;

(d) receiving a reply from one of said nodes of said plurality of nodes;

(e) indicating on said list of said plurality of nodes that said reply was received from said node and connecting the table having the table name to said client;

(f) repeating steps d and e until a reply has been received from each of said plurality of nodes on said list of said plurality of nodes;

(g) collating said replies from said plurality of nodes following step f;

(h) sending a reply to said client and disconnecting the table having the table name if the table name is a duplicate of the table name of a previously connected table.

8. The method of claim 7 further comprising the steps of:

selecting a first reply node of said plurality of nodes having said table; and

sending a disconnect message from said first node to a second reply node of said plurality of nodes having said table.

9. The method of claim 7 further comprising the steps of:

receiving, at each of said plurality of nodes, said broadcast connection request message from said first node;

connecting a table having said table name requested by said client and located on a second node of said plurality of nodes; and

transmitting said reply from said second node to said first node.

10. The method of claim 7 further comprising the steps of:

receiving a node death message for a node disengaged from said network following said building step; and

removing a name of said disengaged node from said list of said plurality of nodes.

11. In a distributed data base management system, a method for fulfilling a connection request message issued by a client comprising the steps of:

receiving a connection request message broadcast from a first node of a network to a second node of said network, said first node having said client and said connection request message having a table name to which connection is requested;

making a connection to a table on said second node if a name of said table is said table name of said connection request message;

marking said table name of said connection request message as being connected if said connection was made;

returning said connection request message to said first node from said second node; and

disconnecting the connected table if the table name is a duplicate of the table name of a previously connected table.

12. The method of claim 11 wherein the disconnecting step comprises the steps of:

receiving at said second node from said first node, a disconnect message for said table having said table name of said connection request message; and

disconnecting said table.