alt Hacker NewsWould be nice if PG supported clustered indexes (Index Organized Tables in Oracle speak) as an option if you have a table thats accessed mostly the same way you can get a index without the write amplification because the table is the index.
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ComputerGuru • today at 12:22 AM
Another option would be a good way of placing indexes on a different physical disk. You could use fast, ephemeral storage like you can for a WAL without amplifying the writes to the same device that is your expensive bottleneck. You could rebuild on data loss.
But it would add complexity to detect out-of-sync indexes and tables.
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Clustered indexes only save up to 2x write amplification in the very rare case where you're indexing the entire table (e.g. if it has very few columns).
However, that is usually the least of your concerns with write amplification. If you don't batch your writes, you can easily get 100x write amplification. For any primary key or any other index not strongly correlated with your INSERTs, you can get perhaps another 100x write amplification even if you batch you writes.