CODEWITHSUNDEEP
vertica
Maxim
Maxim

Reputation: 9961

Performance of INSERT vs INSERT /*+ direct */

Which directive INSERT or INSERT /*+ direct */ has a smallest insertion time? Why?

Upvotes: 1

Views: 1722

Answers (1)

mauro
mauro

Reputation: 5940

When you use the DIRECT hint the INSERT statement will by-pass the Write Optimised Store (WOS - in memory) and write directly to disc into the Read Optimised Store (ROS).

So...

  • the single INSERT without DIRECT could be faster but it depends on several configuration parameter and the WOS status
  • even if you insert in the WOS - sooner or later - a Vertica process (Tuple Mover) will have to move data to disc (ROS).

Upvotes: 6

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