Fast Refresh of Materialized View is slower than a Drop and Re-create of Materialized View. The data in a materialized view is updated by either a complete or incremental refresh. (Also see that you DO have MV Logs on the source tables, else the FAST Refresh's may be falling back to doing COMPLETE Refresh's). I am using a materialized view, and I cant set it to fast refresh because some of the tables are from remote database which does not have materialized view log. This article describes how to troubleshoot slow materialized view complete refresh in order to find the cause of the slowness, and it provides directions towards the solution. You can follow any responses to this entry through the RSS 2.0 feed. I was recently working on tuning – production environment, which had number of materialized views which were scheduled to complete refresh during off hours. Suppose it is already created in the database and you want to query the defination. When I create the materialized view, it took like 20 30 seconds. With this refresh method, only the changes since the last refresh are applied to the materialized view. It took more than 2 3 hours. materialized view refresh is now slow Guess2 Dec 29, 2009 4:17 PM solaris: 5.1 Oracle: 10.1.0.3 FULL REFRESH OF A MATERIALIZED VIEW I am doing a materialized view refresh across a database link. The name “Fast Refresh” is a bit misleading, because there may be situations where a Fast Refresh is slower than a Complete Refresh. You can leave a response , or trackback from your own site. This complete refresh process was very time consuming, also producing a large amount archivelogs & undo. If they are FAST refresh's the most likely cause is a change in Execution Plans. The materialized view fast refresh mechanism is a one-size-fits-all solution, and is probably not efficient for 99% of summary table maintenance operations. Refresh statistics can be … Hi Tom,I had a quick question about why the Fast Refresh of a simple Materialized View subject_mview which is defined on one table, takes much longer than the drop and recreate of the same subject_mview Materialized view, as defined below:I have a log defined on the subject table :===== however when I was trying to refresh it. and total number of records are only around 460,000. Tagged: materialized view, materialized view refresh slow, refreshing data slow. Primary key materialized views allow materialized view master tables to be reorganized without affecting the eligibility of the materialized view for fast refresh. Prior to 10g, when a materialized view is completely refreshed the base table was truncated and then populated with a data. Historical materialized view refresh statistics enable you to understand and analyze materialized view refresh performance over time in your database. (COMPLETE, FAST, FORCE) Since you migrated to 10g there is a slight difference in how Oracle does the refresh. ... many changes happening and many queries running on master table simultaneously with refresh time,then again it will slow down the materialized view refresh. An incremental or fast refresh uses a log table to keep track of changes on the master table. Purpose. Oracle Database - Enterprise Edition - Version 9.2.0.1 and later Information in this document applies to any platform. The master table must contain an enabled primary key constraint, and the defining query of the materialized view must specify all of the primary key columns directly. Oracle materialized view and materialized view log. Slow Materialized View Complete Refresh Issues Resolved…. A more elegant and efficient way to refresh materialized views is a Fast Refresh. See Oracle Support Document ID 553464.1 However, we do not have information about whether your MV Refresh's are COMPLETE or FAST. 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