Ensure example .rrd files have description first (#7179)

### What
* Closes  #7175

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using examples from latest `main` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/7179?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/7179?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG
* [x] If applicable, add a new check to the [release
checklist](https://github.com/rerun-io/rerun/blob/main/tests/python/release_checklist)!
* [x] If have noted any breaking changes to the log API in
`CHANGELOG.md` and the migration guide

- [PR Build Summary](https://build.rerun.io/pr/7179)
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

To run all checks from `main`, comment on the PR with `@rerun-bot
full-check`.

---------

Co-authored-by: Clement Rey <cr.rey.clement@gmail.com>

Cargo.lock

@@ -4486,6 +4486,7 @@ dependencies = [
  "serde",
  "serde_json",
  "serde_yaml",
+ "tempfile",
  "toml",
  "ureq",
  "url",

crates/build/re_dev_tools/Cargo.toml

@@ -38,6 +38,7 @@ rustdoc-types = "0.24.0"
 serde = { workspace = true, features = ["derive"] }
 serde_json.workspace = true
 serde_yaml.workspace = true
+tempfile.workspace = true
 toml = { workspace = true, features = ["parse", "preserve_order"] }
 ureq = { workspace = true, features = ["json"] }
 url.workspace = true

crates/build/re_dev_tools/src/build_examples/install.rs

@@ -36,21 +36,9 @@ impl Install {
         }
 
         let progress = MultiProgress::new();
-        let output = wait_for_output(cmd, "installing examples", &progress)?;
+        wait_for_output(cmd, "installing examples", &progress)?;
 
-        if output.status.success() {
-            println!("Successfully installed examples");
-        } else {
-            anyhow::bail!(
-                "Failed to install examples: \
-                \nstdout: \
-                \n{} \
-                \nstderr: \
-                \n{}",
-                String::from_utf8(output.stdout)?,
-                String::from_utf8(output.stderr)?,
-            );
-        }
+        println!("Successfully installed examples");
 
         Ok(())
     }

crates/build/re_dev_tools/src/build_examples/rrd.rs

@@ -74,39 +74,39 @@ impl Rrd {
 
 impl Example {
     fn build(self, progress: &MultiProgress, output_dir: &Path) -> anyhow::Result<PathBuf> {
-        let rrd_path = output_dir.join(&self.name).with_extension("rrd");
+        let tempdir = tempfile::tempdir()?;
 
-        let mut cmd = Command::new("python3");
-        cmd.arg("-m").arg(&self.name);
-        cmd.arg("--save").arg(&rrd_path);
-        cmd.args(self.script_args);
-
-        let final_args = cmd
-            .get_args()
-            .map(|arg| arg.to_string_lossy().to_string())
-            .collect::<Vec<_>>();
+        let initial_rrd_path = tempdir.path().join(&self.name).with_extension("rrd");
 
-        // Configure flushing so that:
-        // * the resulting file size is deterministic
-        // * the file is chunked into small batches for better streaming
-        cmd.env("RERUN_FLUSH_TICK_SECS", 1_000_000_000.to_string());
-        cmd.env("RERUN_FLUSH_NUM_BYTES", (128 * 1024).to_string());
+        {
+            let mut cmd = Command::new("python3");
+            cmd.arg("-m").arg(&self.name);
+            cmd.arg("--save").arg(&initial_rrd_path);
+            cmd.args(self.script_args);
 
-        let output = wait_for_output(cmd, &self.name, progress)?;
+            // Configure flushing so that:
+            // * the resulting file size is deterministic
+            // * the file is chunked into small batches for better streaming
+            cmd.env("RERUN_FLUSH_TICK_SECS", 1_000_000_000.to_string());
+            cmd.env("RERUN_FLUSH_NUM_BYTES", (128 * 1024).to_string());
 
-        if output.status.success() {
-            Ok(rrd_path)
-        } else {
-            anyhow::bail!(
-                "Failed to run `python3 {}`: \
-                \nstdout: \
-                \n{} \
-                \nstderr: \
-                \n{}",
-                final_args.join(" "),
-                String::from_utf8(output.stdout)?,
-                String::from_utf8(output.stderr)?,
-            );
+            wait_for_output(cmd, &self.name, progress)?;
         }
+
+        // Now run compaction on the result:
+        let final_rrd_path = output_dir.join(&self.name).with_extension("rrd");
+
+        let mut cmd = Command::new("python3");
+        cmd.arg("-m").arg("rerun");
+        cmd.arg("rrd");
+        cmd.arg("compact");
+        // Small chunks for better streaming:
+        cmd.arg("--max-bytes").arg((128 * 1024).to_string());
+        cmd.arg(&initial_rrd_path);
+        cmd.arg("-o").arg(&final_rrd_path);
+
+        wait_for_output(cmd, &format!("{} compaction", self.name), progress)?;
+
+        Ok(final_rrd_path)
     }
 }

crates/build/re_dev_tools/src/build_examples/snippets.rs

@@ -160,11 +160,6 @@ impl Snippet {
         cmd.arg(&self.path);
         cmd.args(&self.extra_args);
 
-        let final_args = cmd
-            .get_args()
-            .map(|arg| arg.to_string_lossy().to_string())
-            .collect::<Vec<_>>();
-
         cmd.envs([
             ("RERUN_FLUSH_NUM_ROWS", "0"),
             ("RERUN_STRICT", "1"),
@@ -175,22 +170,9 @@ impl Snippet {
             ),
         ]);
 
-        let output = wait_for_output(cmd, &self.name, progress)?;
-
-        if output.status.success() {
-            Ok(rrd_path)
-        } else {
-            anyhow::bail!(
-                "Failed to run `python3 {}`: \
-                \nstdout: \
-                \n{} \
-                \nstderr: \
-                \n{}",
-                final_args.join(" "),
-                String::from_utf8(output.stdout)?,
-                String::from_utf8(output.stderr)?,
-            );
-        }
+        wait_for_output(cmd, &self.name, progress)?;
+
+        Ok(rrd_path)
     }
 }
 

crates/build/re_dev_tools/src/build_examples/wait_for_output.rs

@@ -1,17 +1,24 @@
 use std::io::stdout;
 use std::io::IsTerminal;
 use std::process::Command;
-use std::process::Output;
 use std::time::Duration;
 
 use indicatif::MultiProgress;
 use indicatif::ProgressBar;
 
+/// Returns an error on non-zero returncode.
 pub fn wait_for_output(
     mut cmd: Command,
     name: &str,
     progress: &MultiProgress,
-) -> anyhow::Result<Output> {
+) -> anyhow::Result<()> {
+    // Remember what we tried to run, for a better error message:
+    let program = cmd.get_program().to_string_lossy().to_string();
+    let args = cmd
+        .get_args()
+        .map(|arg| arg.to_string_lossy().to_string())
+        .collect::<Vec<_>>();
+
     let progress = progress.add(ProgressBar::new_spinner().with_message(name.to_owned()));
     progress.enable_steady_tick(Duration::from_millis(100));
 
@@ -32,5 +39,18 @@ pub fn wait_for_output(
         println!("{message}");
     }
 
-    Ok(output)
+    if !output.status.success() {
+        let args = args.join(" ");
+        let stdout = String::from_utf8(output.stdout)?;
+        let stderr = String::from_utf8(output.stderr)?;
+        anyhow::bail!(
+            "Failed to run `{program} {args}`: \
+                \nstdout: \
+                \n{stdout} \
+                \nstderr: \
+                \n{stderr}",
+        );
+    }
+
+    Ok(())
 }

crates/store/re_chunk/src/chunk.rs

@@ -833,6 +833,9 @@ impl Chunk {
         (times, counters)
     }
 
+    /// All the [`RowId`] in this chunk.
+    ///
+    /// This could be in any order if this chunk is unsorted.
     #[inline]
     pub fn row_ids(&self) -> impl Iterator<Item = RowId> + '_ {
         let (times, counters) = self.row_ids_raw();

crates/store/re_chunk/src/transport.rs

@@ -613,6 +613,7 @@ impl Chunk {
 
     #[inline]
     pub fn to_arrow_msg(&self) -> ChunkResult<re_log_types::ArrowMsg> {
+        re_tracing::profile_function!();
         self.sanity_check()?;
 
         let transport = self.to_transport()?;

crates/store/re_entity_db/src/entity_db.rs

@@ -466,35 +466,44 @@ impl EntityDb {
             .store_info_msg()
             .map(|msg| Ok(LogMsg::SetStoreInfo(msg.clone())));
 
-        let time_filter = time_selection.map(|(timeline, range)| {
-            (
-                timeline,
-                ResolvedTimeRange::new(range.min.floor(), range.max.ceil()),
-            )
-        });
-
-        let data_messages = self
-            .store()
-            .iter_chunks()
-            .filter(move |chunk| {
-                let Some((timeline, time_range)) = time_filter else {
-                    return true;
-                };
+        let data_messages = {
+            let time_filter = time_selection.map(|(timeline, range)| {
+                (
+                    timeline,
+                    ResolvedTimeRange::new(range.min.floor(), range.max.ceil()),
+                )
+            });
 
-                // TODO(cmc): chunk.slice_time_selection(time_selection)
-                chunk
-                    .timelines()
-                    .get(&timeline)
-                    .map_or(false, |time_column| {
-                        time_range.contains(time_column.time_range().min())
-                            || time_range.contains(time_column.time_range().max())
-                    })
-            })
-            .map(|chunk| {
+            let mut chunks: Vec<&Arc<Chunk>> = self
+                .store()
+                .iter_chunks()
+                .filter(move |chunk| {
+                    let Some((timeline, time_range)) = time_filter else {
+                        return true;
+                    };
+
+                    // TODO(cmc): chunk.slice_time_selection(time_selection)
+                    chunk
+                        .timelines()
+                        .get(&timeline)
+                        .map_or(false, |time_column| {
+                            time_range.contains(time_column.time_range().min())
+                                || time_range.contains(time_column.time_range().max())
+                        })
+                })
+                .collect();
+
+            // Try to roughly preserve the order of the chunks
+            // from how they were originally logged.
+            // See https://github.com/rerun-io/rerun/issues/7175 for why.
+            chunks.sort_by_key(|chunk| chunk.row_id_range().map(|(min, _)| min));
+
+            chunks.into_iter().map(|chunk| {
                 chunk
                     .to_arrow_msg()
                     .map(|msg| LogMsg::ArrowMsg(self.store_id().clone(), msg))
-            });
+            })
+        };
 
         // If this is a blueprint, make sure to include the `BlueprintActivationCommand` message.
         // We generally use `to_messages` to export a blueprint via "save". In that