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docs: Eradicate unpaged SELECTs and warn about their drawbacks #1068

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merged 7 commits into from
Sep 4, 2024
Merged

docs: Eradicate unpaged SELECTs and warn about their drawbacks #1068

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17316cd
docs: rephrase paging purpose in a leftover spot
wprzytula Aug 27, 2024
dc01d0d
docs/data_types: use query_iter for SELECTs
wprzytula Aug 27, 2024
5975fa9
docs: use query_iter in SELECT example in README
wprzytula Aug 27, 2024
112ed5d
docs: use query_iter for SELECT in quickstart example
wprzytula Aug 27, 2024
8e4c555
docs: add caveat about unpaged SELECTs' drawbacks
wprzytula Aug 27, 2024
663e09d
docs/paged: remove leftover PageSize try_into()
wprzytula Aug 29, 2024
8604a33
docs: exhaustive overview of statements & best practices
wprzytula Aug 29, 2024
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8 changes: 5 additions & 3 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -15,13 +15,15 @@ The [documentation book](https://rust-driver.docs.scylladb.com/stable/index.html

## Examples
```rust
use futures::TryStreamExt;

let uri = "127.0.0.1:9042";

let session: Session = SessionBuilder::new().known_node(uri).build().await?;

let result = session.query_unpaged("SELECT a, b, c FROM ks.t", &[]).await?;
let mut iter = result.rows_typed::<(i32, i32, String)>()?;
while let Some((a, b, c)) = iter.next().transpose()? {
let raw_iter = session.query_iter("SELECT a, b, c FROM ks.t", &[]).await?;
let mut iter = raw_iter.into_typed::<(i32, i32, String)>();
while let Some((a, b, c)) = iter.try_next().await? {
println!("a, b, c: {}, {}, {}", a, b, c);
}
```
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8 changes: 4 additions & 4 deletions docs/source/data-types/blob.md
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Original file line number Diff line number Diff line change
Expand Up @@ -4,10 +4,11 @@

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;

// Insert some blob into the table as a Vec<u8>
// We can insert it by reference to not move the whole blob
Expand All @@ -17,9 +18,8 @@ session
.await?;

// Read blobs from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(Vec<u8>,)>()?;
while let Some((blob_value,)) = iter.next().transpose()? {
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[]).await?.into_typed::<(Vec<u8>,)>();
while let Some((blob_value,)) = iter.try_next().await? {
println!("{:?}", blob_value);
}
# Ok(())
Expand Down
64 changes: 37 additions & 27 deletions docs/source/data-types/collections.md
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Original file line number Diff line number Diff line change
Expand Up @@ -5,10 +5,11 @@

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;

// Insert a list of ints into the table
let my_list: Vec<i32> = vec![1, 2, 3, 4, 5];
Expand All @@ -17,9 +18,8 @@ session
.await?;

// Read a list of ints from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(Vec<i32>,)>()?;
while let Some((list_value,)) = iter.next().transpose()? {
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[]).await?.into_typed::<(Vec<i32>,)>();
while let Some((list_value,)) = iter.try_next().await? {
println!("{:?}", list_value);
}
# Ok(())
Expand All @@ -31,10 +31,11 @@ while let Some((list_value,)) = iter.next().transpose()? {

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;

// Insert a set of ints into the table
let my_set: Vec<i32> = vec![1, 2, 3, 4, 5];
Expand All @@ -43,21 +44,23 @@ session
.await?;

// Read a set of ints from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(Vec<i32>,)>()?;
while let Some((list_value,)) = iter.next().transpose()? {
println!("{:?}", list_value);
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.into_typed::<(Vec<i32>,)>();
while let Some((set_value,)) = iter.try_next().await? {
println!("{:?}", set_value);
}
# Ok(())
# }
```

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;
use std::collections::HashSet;

// Insert a set of ints into the table
Expand All @@ -67,21 +70,23 @@ session
.await?;

// Read a set of ints from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(HashSet<i32>,)>()?;
while let Some((list_value,)) = iter.next().transpose()? {
println!("{:?}", list_value);
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.into_typed::<(HashSet<i32>,)>();
while let Some((set_value,)) = iter.try_next().await? {
println!("{:?}", set_value);
}
# Ok(())
# }
```

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;
use std::collections::BTreeSet;

// Insert a set of ints into the table
Expand All @@ -91,10 +96,11 @@ session
.await?;

// Read a set of ints from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(BTreeSet<i32>,)>()?;
while let Some((list_value,)) = iter.next().transpose()? {
println!("{:?}", list_value);
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.into_typed::<(BTreeSet<i32>,)>();
while let Some((set_value,)) = iter.try_next().await? {
println!("{:?}", set_value);
}
# Ok(())
# }
Expand All @@ -105,10 +111,11 @@ while let Some((list_value,)) = iter.next().transpose()? {

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;
use std::collections::HashMap;

// Insert a map of text and int into the table
Expand All @@ -120,9 +127,10 @@ session
.await?;

// Read a map from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(HashMap<String, i32>,)>()?;
while let Some((map_value,)) = iter.next().transpose()? {
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.into_typed::<(HashMap<String, i32>,)>();
while let Some((map_value,)) = iter.try_next().await? {
println!("{:?}", map_value);
}
# Ok(())
Expand All @@ -131,10 +139,11 @@ while let Some((map_value,)) = iter.next().transpose()? {

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;
use std::collections::BTreeMap;

// Insert a map of text and int into the table
Expand All @@ -146,9 +155,10 @@ session
.await?;

// Read a map from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(BTreeMap<String, i32>,)>()?;
while let Some((map_value,)) = iter.next().transpose()? {
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.into_typed::<(BTreeMap<String, i32>,)>();
while let Some((map_value,)) = iter.try_next().await? {
println!("{:?}", map_value);
}
# Ok(())
Expand Down
10 changes: 6 additions & 4 deletions docs/source/data-types/counter.md
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Original file line number Diff line number Diff line change
Expand Up @@ -4,16 +4,18 @@

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;
use scylla::frame::value::Counter;

// Read counter from the table
let result = session.query_unpaged("SELECT c FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(Counter,)>()?;
while let Some((counter_value,)) = iter.next().transpose()? {
let mut iter = session.query_iter("SELECT c FROM keyspace.table", &[])
.await?
.into_typed::<(Counter,)>();
while let Some((counter_value,)) = iter.try_next().await? {
let counter_int_value: i64 = counter_value.0;
println!("{}", counter_int_value);
}
Expand Down
38 changes: 20 additions & 18 deletions docs/source/data-types/date.md
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Expand Up @@ -14,11 +14,12 @@ However, for most use cases other types are more practical. See following sectio

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::frame::value::CqlDate;
use scylla::IntoTypedRows;
use futures::TryStreamExt;

// 1970-01-08
let to_insert = CqlDate((1 << 31) + 7);
Expand All @@ -29,14 +30,11 @@ session
.await?;

// Read raw Date from the table
if let Some(rows) = session
.query_unpaged("SELECT a FROM keyspace.table", &[])
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.rows
{
for row in rows.into_typed::<(CqlDate,)>() {
let (date_value,): (CqlDate,) = row?;
}
.into_typed::<(CqlDate,)>();
while let Some((date_value,)) = iter.try_next().await? {
// ...
}
# Ok(())
# }
Expand All @@ -52,11 +50,12 @@ If full range is not required and `chrono` feature is enabled,
```rust
# extern crate chrono;
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use chrono::NaiveDate;
use scylla::IntoTypedRows;
use futures::TryStreamExt;

// 2021-03-24
let to_insert = NaiveDate::from_ymd_opt(2021, 3, 24).unwrap();
Expand All @@ -67,10 +66,11 @@ session
.await?;

// Read NaiveDate from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(NaiveDate,)>()?;
while let Some((date_value,)) = iter.next().transpose()? {
println!("{:?}", date_value);
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.into_typed::<(NaiveDate,)>();
while let Some((date_value,)) = iter.try_next().await? {
// ...
}
# Ok(())
# }
Expand All @@ -86,10 +86,11 @@ documentation to get more info.
```rust
# extern crate scylla;
# extern crate time;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;
use time::{Date, Month};

// 2021-03-24
Expand All @@ -101,10 +102,11 @@ session
.await?;

// Read Date from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(Date,)>()?;
while let Some((date_value,)) = iter.next().transpose()? {
println!("{:?}", date_value);
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.into_typed::<(Date,)>();
while let Some((date_value,)) = iter.try_next().await? {
// ...
}
# Ok(())
# }
Expand Down
22 changes: 13 additions & 9 deletions docs/source/data-types/decimal.md
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Expand Up @@ -7,10 +7,11 @@ Without any feature flags, the user can interact with `decimal` type by making u

```rust
# extern crate scylla;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;
use scylla::frame::value::CqlDecimal;
use std::str::FromStr;

Expand All @@ -22,10 +23,11 @@ session
.await?;

// Read a decimal from the table
if let Some(rows) = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?.rows {
for row in rows.into_typed::<(CqlDecimal,)>() {
let (decimal_value,): (CqlDecimal,) = row?;
}
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.into_typed::<(CqlDecimal,)>();
while let Some((decimal_value,)) = iter.try_next().await? {
println!("{:?}", decimal_value);
}
# Ok(())
# }
Expand All @@ -38,10 +40,11 @@ To make use of `bigdecimal::Bigdecimal` type, user should enable `bigdecimal-04`
```rust
# extern crate scylla;
# extern crate bigdecimal;
# extern crate futures;
# use scylla::Session;
# use std::error::Error;
# async fn check_only_compiles(session: &Session) -> Result<(), Box<dyn Error>> {
use scylla::IntoTypedRows;
use futures::TryStreamExt;
use bigdecimal::BigDecimal;
use std::str::FromStr;

Expand All @@ -52,9 +55,10 @@ session
.await?;

// Read a decimal from the table
let result = session.query_unpaged("SELECT a FROM keyspace.table", &[]).await?;
let mut iter = result.rows_typed::<(BigDecimal,)>()?;
while let Some((decimal_value,)) = iter.next().transpose()? {
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.into_typed::<(BigDecimal,)>();
while let Some((decimal_value,)) = iter.try_next().await? {
println!("{:?}", decimal_value);
}
# Ok(())
Expand Down
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