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. Thanks, Bradley
(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.