Home/ Questions/Q 3212402
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-17T14:50:05+00:00

I was indexing a huge table today containing 2 billion records. I thought MySQL

  • 0

I was indexing a huge table today containing 2 billion records. I thought MySQL would eat away my 2TB drive… The disk consumption kept increasing to 400GB and then 500GB and then finally drops to 180GB and MySQL says successfully added the index. Why the space increase and what happened in the end? Can someone please give me some pointers?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Incidentally yesterday I answered a question on how to make index creation faster in MySQL, and the following came out from my research:

    The CREATE INDEX and DROP INDEX commands work by creating a new, empty table defined with the requested set of indexes. It then copies the existing rows to the new table one-by-one, updating the indexes as it goes. Inserting entries into the indexes in this fashion, where the key values are not sorted, requires random access to the index nodes, and is far from optimal. After all rows from the original table are copied, the old table is dropped and the copy is renamed with the name of the original table.

    Source: Overview of Fast Index Creation

    • 0