Contents
Is reindex safe?
Reindexing is not dangerous and can not harm data consistency. However, if you have time critical writes, you may loose data if the table is locked and the DML is aborted. Reindexing should not take a lot of time, but will usually involve reading the whole table, sorting the index fields and writing a new index.
How does postgres vacuum work?
VACUUM reclaims storage occupied by dead tuples. In normal PostgreSQL operation, tuples that are deleted or obsoleted by an update are not physically removed from their table; they remain present until a VACUUM is done. VACUUM ANALYZE performs a VACUUM and then an ANALYZE for each selected table.
Do you need to reindex a table in cluster?
You do not need to reindex, because CLUSTER effectively does it for you. More specifically, CLUSTER locks the source table then creates a new copy of it ordered according to the target index. It creates indexes on the new copy then replaces the old table and indexes with the new ones.
When is the best time to do reindexing?
Here are some recommendations when considering reindexing: Only enable reindexing (database configuration) during off-peak hours. The duration to complete the reindex will increase, but performance during peak hours will be better. Changes in the cluster configuration may require rebalancing content across forests.
How does reindexing work when indexes are changed?
When the indexes are changed, the server will begin the process of reindexing all affected content. In most cases, this will include all documents in a database, but the server does try to reindex only the fragments that contain content that would be populated in the added/removed index.
When do I need to reindex a fragment?
If no index changes have been made, the server will simply reindex zero fragments. If the changes include index settings, however, the server will find that some/all fragments may need to be reindexed.