35 lines
1.8 KiB
Rust
35 lines
1.8 KiB
Rust
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// Timestamp to versionstamp tests
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// This translation mechanism is currently used by the garbage collector to determine which change feed entries to delete.
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//
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// FAQ:
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// Q: What’s the difference between database TS and database VS?
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// A: Timestamps are basically seconds since the unix epoch.
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// Versionstamps can be anything that is provided by our TSO.
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// Q: Why do we need to translate timestamps to versionstamps?
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// A: The garbage collector needs to know which change feed entries to delete.
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// However our SQL syntax `DEFINE DATABASE foo CHANGEFEED 1h` let the user specify the expiration in a duration, not a delta in the versionstamp.
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// We need to translate the timestamp to the versionstamp due to that; `now - 1h` to a key suffixed by the versionstamp.
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#[tokio::test]
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#[serial]
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async fn timestamp_to_versionstamp() {
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// Create a new datastore
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let ds = new_ds().await;
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// Give the current versionstamp a timestamp of 0
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let mut tx = ds.transaction(true, false).await.unwrap();
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tx.set_timestamp_for_versionstamp(0, "myns", "mydb", true).await.unwrap();
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let vs1 = tx.get_versionstamp_from_timestamp(0, "myns", "mydb", true).await.unwrap().unwrap();
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tx.commit().await.unwrap();
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// Give the current versionstamp a timestamp of 1
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let mut tx = ds.transaction(true, false).await.unwrap();
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tx.set_timestamp_for_versionstamp(1, "myns", "mydb", true).await.unwrap();
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let vs2 = tx.get_versionstamp_from_timestamp(1, "myns", "mydb", true).await.unwrap().unwrap();
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tx.commit().await.unwrap();
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// Give the current versionstamp a timestamp of 2
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let mut tx = ds.transaction(true, false).await.unwrap();
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tx.set_timestamp_for_versionstamp(2, "myns", "mydb", true).await.unwrap();
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let vs3 = tx.get_versionstamp_from_timestamp(2, "myns", "mydb", true).await.unwrap().unwrap();
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tx.commit().await.unwrap();
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assert!(vs1 < vs2);
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assert!(vs2 < vs3);
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}
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