wingfoil 4.0.1

graph based stream processing framework
Documentation 
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# KDB+ Read Example

Reads from a KDB+ table using 10-second time slices over a 100-second window.
Each chunk issues a separate time-bounded query, demonstrating the time slicing feature.

## Setup

Start KDB+ on port 5000 and create a `prices` table with data spread across multiple 10s chunks:

```sh
q -p 5000
```

```q
prices:([]time:`timestamp$();sym:`symbol$();mid:`float$())
`prices insert (2000.01.01D00:00:05.000000000;`AAPL;150.25)
`prices insert (2000.01.01D00:00:15.000000000;`GOOG;2800.50)
`prices insert (2000.01.01D00:00:25.000000000;`MSFT;310.75)
`prices insert (2000.01.01D00:00:55.000000000;`AAPL;151.00)
`prices insert (2000.01.01D00:01:25.000000000;`GOOG;2805.00)
```

## Run

```sh
RUST_LOG=info cargo run --example kdb_read --features kdb
```

## Code

```rust
#[derive(Debug, Clone, Default)]
struct Price {
    sym: Sym,
    mid: f64,
}

impl KdbDeserialize for Price {
    fn from_kdb_row(
        row: Row<'_>,
        _columns: &[String],
        interner: &mut SymbolInterner,
    ) -> Result<(NanoTime, Self), KdbError> {
        let time = row.get_timestamp(0)?;
        Ok((time, Price {
            sym: row.get_sym(1, interner)?,
            mid: row.get(2)?.get_float()?,
        }))
    }
}

kdb_read::<Price, _>(
    conn,
    Duration::from_secs(10),
    |(t0, t1), _date, _iter| {
        format!(
            "select time, sym, mid from prices \
             where time >= (`timestamp$){}j, time < (`timestamp$){}j",
            t0.to_kdb_timestamp(),
            t1.to_kdb_timestamp(),
        )
    },
)
.logged("prices", Info)
.run(
    RunMode::HistoricalFrom(NanoTime::from_kdb_timestamp(0)),
    RunFor::Duration(Duration::from_secs(100)),
)?;
```

## Output

```
[INFO prices] Price { sym: AAPL, mid: 150.25 }
[INFO prices] Price { sym: GOOG, mid: 2800.5 }
[INFO prices] Price { sym: MSFT, mid: 310.75 }
[INFO prices] Price { sym: AAPL, mid: 151.0 }
[INFO prices] Price { sym: GOOG, mid: 2805.0 }
```