Santosh Kangane

In last post I explained  PostgreSQL 9.1 Vs 9.2 .    In this post I will explain 9.3. PostgreSQL 9.1 Vs 9.3 I)      Stability:  PostgreSQL 9.3 released on 9 th  Sept 2013. II)     Performance Improvement: Collect and use histograms of upper and lower bounds, as well as range lengths, for range types  Improve optimizer's cost estimation for index access Improve optimizer's hash table size estimate for doing DISTINCT via hash aggregation Suppress no-op Result and Limit plan nodes  Reduce optimizer overhead by not keeping plans on the basis of cheap start-up cost when the optimizer only cares about total cost overall III)     Other Key New Features: Streaming-Only Remastering: "Remastering" is the process whereby a replica in a set of replicas becomes the new master for all of the other replicas. For example: Master M1 is replicating to replicas R1, R2 and R3. Master M1 needs to be taken d...

Recently one of my customer asked me what is advantage of upgrading PostgreSQL from 9.1 to 9.2 or 9.3? In this series of post I will try to explain the impact & benefit of moving to 9.2 or 9.3 Key Point of Evaluation: Stability of Product Performance Improvement Other Key New Features Compatibility with Existing Applications Cost of Upgreadation. PostgreSQL 9.1 Vs 9.2 I)      Stability:  PostgreSQL 9.2 released on 10 th  Sept 2012. II)     Performance Improvement: Index Only scan:   (Very important feature)  9.1 PgSQL has to scan both index and Table segment to show the final result set as it needs to check the tuple visibility. In 9.2 PgSQL has been improved to allow queries to retrieve data only from indexes, avoiding heap access. Show the result just by scanning the index segment if all the columns in query are present in Index segment itself. There by reduces IO. PgSQL manages and update visibility...