You are viewing a plain text version of this content. The canonical link for it is here.
Posted to github@arrow.apache.org by "tustvold (via GitHub)" <gi...@apache.org> on 2023/05/16 18:50:10 UTC
[GitHub] [arrow-datafusion] tustvold opened a new pull request, #6366: Parallel parquet schema inference
tustvold opened a new pull request, #6366:
URL: https://github.com/apache/arrow-datafusion/pull/6366
# Which issue does this PR close?
<!--
We generally require a GitHub issue to be filed for all bug fixes and enhancements and this helps us generate change logs for our releases. You can link an issue to this PR using the GitHub syntax. For example `Closes #123` indicates that this PR will close issue #123.
-->
Closes #.
# Rationale for this change
<!--
Why are you proposing this change? If this is already explained clearly in the issue then this section is not needed.
Explaining clearly why changes are proposed helps reviewers understand your changes and offer better suggestions for fixes.
-->
Inferring parquet metadata is largely IO bound, especially when interacting with remote stores or when there is no parquet size hint. As such it makes sense to attempt to run in parallel.
# What changes are included in this PR?
<!--
There is no need to duplicate the description in the issue here but it is sometimes worth providing a summary of the individual changes in this PR.
-->
# Are these changes tested?
<!--
We typically require tests for all PRs in order to:
1. Prevent the code from being accidentally broken by subsequent changes
2. Serve as another way to document the expected behavior of the code
If tests are not included in your PR, please explain why (for example, are they covered by existing tests)?
-->
# Are there any user-facing changes?
<!--
If there are user-facing changes then we may require documentation to be updated before approving the PR.
-->
<!--
If there are any breaking changes to public APIs, please add the `api change` label.
-->
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org
[GitHub] [arrow-datafusion] alamb commented on a diff in pull request #6366: Concurrent Parquet Schema Inference
Posted by "alamb (via GitHub)" <gi...@apache.org>.
alamb commented on code in PR #6366:
URL: https://github.com/apache/arrow-datafusion/pull/6366#discussion_r1196984754
##########
datafusion/core/src/datasource/file_format/parquet.rs:
##########
@@ -151,12 +152,12 @@ impl FileFormat for ParquetFormat {
store: &Arc<dyn ObjectStore>,
objects: &[ObjectMeta],
) -> Result<SchemaRef> {
- let mut schemas = Vec::with_capacity(objects.len());
- for object in objects {
- let schema =
- fetch_schema(store.as_ref(), object, self.metadata_size_hint).await?;
- schemas.push(schema)
- }
+ let schemas: Vec<_> = futures::stream::iter(objects)
+ .map(|object| fetch_schema(store.as_ref(), object, self.metadata_size_hint))
+ .boxed() // Workaround https://github.com/rust-lang/rust/issues/64552
+ .buffered(32)
Review Comment:
I think the `32` should at least be a named constant so it is more discoverable
What do you think about potentially using the same value as in https://github.com/apache/arrow-datafusion/pull/6183:
```
const CONCURRENCY_LIMIT: usize = 100;
```
(I sort of imagine some day someone will want to make that a configuration knob rather than a constant so using the same constant in the code will make it easier to find where they are used)
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org
[GitHub] [arrow-datafusion] alamb commented on a diff in pull request #6366: Concurrent Parquet Schema Inference
Posted by "alamb (via GitHub)" <gi...@apache.org>.
alamb commented on code in PR #6366:
URL: https://github.com/apache/arrow-datafusion/pull/6366#discussion_r1198822142
##########
datafusion/core/src/datasource/file_format/parquet.rs:
##########
@@ -151,12 +152,12 @@ impl FileFormat for ParquetFormat {
store: &Arc<dyn ObjectStore>,
objects: &[ObjectMeta],
) -> Result<SchemaRef> {
- let mut schemas = Vec::with_capacity(objects.len());
- for object in objects {
- let schema =
- fetch_schema(store.as_ref(), object, self.metadata_size_hint).await?;
- schemas.push(schema)
- }
+ let schemas: Vec<_> = futures::stream::iter(objects)
+ .map(|object| fetch_schema(store.as_ref(), object, self.metadata_size_hint))
+ .boxed() // Workaround https://github.com/rust-lang/rust/issues/64552
+ .buffered(32)
Review Comment:
https://github.com/apache/arrow-datafusion/pull/6389
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org
[GitHub] [arrow-datafusion] alamb commented on a diff in pull request #6366: Concurrent Parquet Schema Inference
Posted by "alamb (via GitHub)" <gi...@apache.org>.
alamb commented on code in PR #6366:
URL: https://github.com/apache/arrow-datafusion/pull/6366#discussion_r1198818162
##########
datafusion/core/src/datasource/file_format/parquet.rs:
##########
@@ -151,12 +152,12 @@ impl FileFormat for ParquetFormat {
store: &Arc<dyn ObjectStore>,
objects: &[ObjectMeta],
) -> Result<SchemaRef> {
- let mut schemas = Vec::with_capacity(objects.len());
- for object in objects {
- let schema =
- fetch_schema(store.as_ref(), object, self.metadata_size_hint).await?;
- schemas.push(schema)
- }
+ let schemas: Vec<_> = futures::stream::iter(objects)
+ .map(|object| fetch_schema(store.as_ref(), object, self.metadata_size_hint))
+ .boxed() // Workaround https://github.com/rust-lang/rust/issues/64552
+ .buffered(32)
Review Comment:
I'll make this change as a follow up
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org
[GitHub] [arrow-datafusion] alamb merged pull request #6366: Concurrent Parquet Schema Inference
Posted by "alamb (via GitHub)" <gi...@apache.org>.
alamb merged PR #6366:
URL: https://github.com/apache/arrow-datafusion/pull/6366
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org
[GitHub] [arrow-datafusion] tustvold commented on a diff in pull request #6366: Parallel parquet schema inference
Posted by "tustvold (via GitHub)" <gi...@apache.org>.
tustvold commented on code in PR #6366:
URL: https://github.com/apache/arrow-datafusion/pull/6366#discussion_r1195569323
##########
datafusion/core/src/datasource/file_format/parquet.rs:
##########
@@ -151,12 +152,12 @@ impl FileFormat for ParquetFormat {
store: &Arc<dyn ObjectStore>,
objects: &[ObjectMeta],
) -> Result<SchemaRef> {
- let mut schemas = Vec::with_capacity(objects.len());
- for object in objects {
- let schema =
- fetch_schema(store.as_ref(), object, self.metadata_size_hint).await?;
- schemas.push(schema)
- }
+ let schemas: Vec<_> = futures::stream::iter(objects)
+ .map(|object| fetch_schema(store.as_ref(), object, self.metadata_size_hint))
+ .boxed() // Workaround https://github.com/rust-lang/rust/issues/64552
Review Comment:
No I cannot explain why this works... But for some unknown reason it placates the compiler
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org
[GitHub] [arrow-datafusion] alamb commented on a diff in pull request #6366: Concurrent Parquet Schema Inference
Posted by "alamb (via GitHub)" <gi...@apache.org>.
alamb commented on code in PR #6366:
URL: https://github.com/apache/arrow-datafusion/pull/6366#discussion_r1196982227
##########
datafusion/core/src/datasource/file_format/parquet.rs:
##########
@@ -151,12 +152,12 @@ impl FileFormat for ParquetFormat {
store: &Arc<dyn ObjectStore>,
objects: &[ObjectMeta],
) -> Result<SchemaRef> {
- let mut schemas = Vec::with_capacity(objects.len());
- for object in objects {
- let schema =
- fetch_schema(store.as_ref(), object, self.metadata_size_hint).await?;
- schemas.push(schema)
- }
+ let schemas: Vec<_> = futures::stream::iter(objects)
+ .map(|object| fetch_schema(store.as_ref(), object, self.metadata_size_hint))
+ .boxed() // Workaround https://github.com/rust-lang/rust/issues/64552
Review Comment:
I found using streams was a similarly frustrating experience where the compiler give you an opaque error message (and opaque is being polite)
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org