README for HP Neoview Release 2.4

Automatic Query Retry
Prior to Release 2.4, most of the errors raised during query execution were returned to the
application. Many of these errors were transient errors that were related to locking, timeouts,
resource limitations, and other issues. If retried, such errors would very likely succeed, but the
retry responsibility belonged to the application. In Release 2.4, the Neoview platform automatically
retries the operation if it encounters certain errors. The ID of the original query is the ID used
for the retry.
Retry is not performed for these scenarios:
• One or more rows have been returned to the application.
• The query requires a transaction.
• The query is running under a user defined transaction and the transaction was aborted when
the failure occurred.
• The feature was turned off by setting CQD auto_query_retry to OFF.
• The query is a dynamic query issued from an embedded program.
• The query contains a stored procedure.
• The query is a Publish-Subscribe query with Stream access.
• The query contains a compound statement.
These errors are retried :
• Communication failure with an ESP: 2034/201, 2034/246, 2034/249.
• DP2 or FS memory usage errors: 8551/30, 8551/31.
• Locked row timeout: 8550/73, 8551/73.
• Invalid transaction ID: 8550/78, 8551/78
• Opens that are lost or no longer valid: 8574/0
• Redefinition timestamp mismatch: 8575/0
• Schema level security label timestamp mismatch: 8575/0
• Similarity Check Failure: 8579/0
• Unavailable partitions: 8580/0
• Unavailable ESPs: 8596/0
• View not found: 8598/0
• Transaction mode mismatch: 8814/0
A new SET SESSION DEFAULT command has been added to allow you to add, delete or modify
errors that should be retried.
SET SESSION DEFAULT AQR ENTRIES value[| value]
value is:
[sign],{SQL_code, operating_system_error, retries,delay}
Sign indicates the action to be performed for an entry.
• + (plus sign) to add an entry. This is the default.
• – (minus sign) to delete an entry.
• . (period) to modify an existing entry.
This is an optional parameter.
SQL Code is an unsigned number indicating the error on which to retry.
This parameter is required.
Operating System Error
is the file System error number returned with SQL_code. The
default is 0 (zero).
Retries is the number of times to retry the query. The default is 1.
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