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SAP HANA Developer Guide - Get a Free Blog

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● Preprocessing<br />

● Preprocessed<br />

● Indexing<br />

● Error<br />

If the original column entry is modified or deleted during text processing, the queue is notified and, if necessary,<br />

the entry is preprocessed again.<br />

Note: The content of the queue is not made persistent at any stage. If the <strong>HANA</strong> index server process fails,<br />

the queue data is lost and the queue manager automatically restarts the process for those entries that<br />

were not already processed. Any incomplete text preprocessing is restarted from the beginning.<br />

Flush Scheduling<br />

When you create an asynchronous full text index, you can specify when documents are removed from the queue<br />

after they are preprocessed and inserted into the full text index; this is called flushing. You can schedule flushing<br />

based on either time or the number of documents. To do this, when you create the full text index, define one of the<br />

following clauses with the ASYNC parameter:<br />

● FLUSH EVERY (n) MINUTES<br />

● FLUSH AFTER (n) DOCUMENTS<br />

● FLUSH EVERY (n) MINUTES OR AFTER (m) DOCUMENTS<br />

Note: You cannot specify negatives values for minutes or documents.<br />

To determine when the queue of an existing full text index is flushed, see the FLUSH_EVERY_MINUTES and<br />

FLUSH_AFTER_ROWS attributes in the view FULLTEXT_INDEXES.<br />

Related Links<br />

Manipulating Queue Processing [page 241]<br />

By default, queues are active initially and run automatically based on the parameters you specify when<br />

creating the full text index. However, if necessary, you can manually manipulate the processing of an existing<br />

queue.<br />

Manipulating Queue Processing<br />

By default, queues are active initially and run automatically based on the parameters you specify when creating<br />

the full text index. However, if necessary, you can manually manipulate the processing of an existing queue.<br />

To manipulate the processing of a queue, the following commands are available:<br />

● FLUSH<br />

Updates the full text index with the documents in the queue which have already been processed and removes<br />

them from the queue.<br />

● SUSPEND<br />

Suspends the full text index processing queue<br />

● ACTIVATE<br />

<strong>SAP</strong> <strong>HANA</strong> <strong>Developer</strong> <strong>Guide</strong><br />

Enabling Search<br />

P U B L I C<br />

© 2012 <strong>SAP</strong> AG. All rights reserved. 241

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