Then you likely measure how fast PG updates in-memory buffer rather than actual writes to disk. I cannot find links to discussions where people mentioned that desktop OS and consumer grade SSDs can delay writes to get more performance. This is what ChatGPT has to say about this.
Historically and even in recent versions, macOS has had issues where fsync() does not guarantee data is truly flushed to persistent storage (e.g., SSD or spinning disk). This is due to:
• Disk write caching: macOS may acknowledge fsync() even if the data is just in the drive’s volatile cache (not flushed to physical storage).
• APFS quirks: The Apple File System (APFS) has been reported to coalesce or delay flushes more aggressively than other filesystems (like ext4 or xfs).
• SSD controller behavior: Even if macOS passes the flush through, the SSD itself may lie unless it supports FLUSH_CACHE and has power-loss protection.
Then you likely measure how fast PG updates in-memory buffer rather than actual writes to disk. I cannot find links to discussions where people mentioned that desktop OS and consumer grade SSDs can delay writes to get more performance. This is what ChatGPT has to say about this.
Historically and even in recent versions, macOS has had issues where fsync() does not guarantee data is truly flushed to persistent storage (e.g., SSD or spinning disk). This is due to: • Disk write caching: macOS may acknowledge fsync() even if the data is just in the drive’s volatile cache (not flushed to physical storage). • APFS quirks: The Apple File System (APFS) has been reported to coalesce or delay flushes more aggressively than other filesystems (like ext4 or xfs). • SSD controller behavior: Even if macOS passes the flush through, the SSD itself may lie unless it supports FLUSH_CACHE and has power-loss protection.