Lob locators

A computer-readable medium carrying one or more sequences of one or more instructions for performing operations on large objects (LOBs) in a database system that includes a server and one or more clients, the one or more sequences of one or more instructions including instructions which, when executed by the server, cause the server to perform the steps of:

• the server receiving from a client of said one or more clients a command that identifies a row of a table, wherein the table includes a LOB column that contains LOBs;
• the server responding to the command by sending the client a first set of data that includes a locator for a LOB that belongs in the LOB column of the row;
• wherein said locator includes a LOB identifier that uniquely identifies the LOB and snapshot information that identifies a particular version of the LOB;
• the server receiving a request from the client to perform an operation on the LOB, wherein the operation does not modify the LOB, the request passing the locator for the LOB to a routine provided by the server;
• and
• the server performing the operation on the particular version of the LOB that is identified in the snapshot information contained in the locator passed to the server by the client.

A database system comprising:

• one or more computer systems coupled to allow communication between processes executing on said one or more computer systems;
• a client executing on at least one of said one or more computer systems;
• a server executing on at least one of said one or more computer systems;
• said client being configured to:
• send a command that identifies a row in a table to a server, wherein the table includes a LOB column that contains LOBs;
• receive from the server a first set of data that includes a locator for a LOB that belongs in the LOB column of the row;
• wherein said locator includes a LOB identifier that uniquely identifies the LOB and snapshot information that identifies a particular version of the LOB;
• and
• request the server to perform an operation on the LOB by passing the locator for the LOB to a routine provided by the server;
• and
• said server being configured to:
• receive from said client said command;
• responding to the command by sending the client said first set of data;
• and
• if the operation does not modify the LOB, performing the operation on the particular version of the LOB that is identified in the snapshot information contained in the locator passed to the server by the client.

A database server configured to

• provide to a client, in response to a command from the client that identifies a row of a table having a large object (LOB) column that contains LOBs, a first set of data that includes a locator for a LOB that belongs in the LOB column of the row, wherein the locator includes a LOB identifier that uniquely identifies the LOB and snapshot information that identifies a particular version of the LOB;
• receive a request from the client to perform an operation on the LOB, wherein the request includes the locator containing the snapshot information that identifies the particular version of the LOB;
• determine whether the operation will modify the LOB;
• and
• if the operation will not modify the LOB, then cause the operation to be performed on the particular version of the LOB that is identified in the snapshot information contained in the locator.