Ravi Sir's Cards › AWS
Projection cost
This revision card explains Projection cost. It starts from the need that ALL projections quietly double storage and writes. It describes KEYS_ONLY / INCLUDE / ALL — project only what Query returns need. The how-to section notes sketch needed attrs , then choose projection , then estimate write amplification. An example on the card is elena Petrova budgets GSI writes before launch week.
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What this card says
Why do we need it?
ALL projections quietly double storage and writes.
What is it?
KEYS_ONLY / INCLUDE / ALL — project only what Query returns need.
KEYS_ONLY
How to do it
Sketch needed attrs → choose projection → estimate write amplification.
Example
Elena Petrova budgets GSI writes before launch week.