SQLite Forum

Window RAM Disk no better than local SSD?

Window RAM Disk no better than local SSD?

(1) By anonymous on 2021-05-17 21:47:42 [link]

I'm trying to build a SQLite database completely on an appropriately sized Windows 10 RAM disk (R:), where both inputs and outputs are on R:.  I am using sqlite3.exe command-line tool < test.ddl

Even though I'm setting TMP to R:\ I get the same run-time as when using the local (SSD) disk for inputs and outputs.

What I/O am I missing?  I would expect the .imports, DDL/DML, and writes to be much, much faster than SSD.


(2) By Keith Medcalf (kmedcalf) on 2021-05-17 22:55:01 in reply to 1 [link]

Windows does not have RAMDISKs, that is the purview of Third-Party software.  Perhaps the THird-Party software is buggered up.

Alternatively, perhaps you are CPU limited, not I/O limited.

(3) By Larry Brasfield (larrybr) on 2021-05-17 23:14:43 in reply to 1

Before declaring puzzlement, I would want to know whether OS-level caching being done for the SSD store was causing its performance as seen by the sqlite3.exe process to approach RAM-disk performance. If the caching lets that process proceed without waiting for bits to reach NV-RAM, delays would be similar rather than much (or much, much) different.

(4) By anonymous on 2021-05-18 10:05:00 in reply to 1 [link]

What is your the value set for "synchronous"? In what "journal_mode"?

If you are not actually syncing to desk then expect pretty similar performance since data will be mostly residing in RAM anyways.