feat: Avoid small batches in Exchange #12010
Conversation
facebook-github-bot
added
the
CLA Signed
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
✅ Deploy Preview for meta-velox canceled.
|
Summary: X-link: facebookincubator/velox#12010 Prevent exchange client from unblocking to early. Unblocking to early impedes effectiveness of page merging. When the cost of creating a vector is high (for example for data sets with high number of columns) creating small pages can make queries significantly less efficient. For example it was observed that when network is congested and Exchange buffers are not filled up as fast query may experience CPU efficiency drop up to 4x: T211034421 Differential Revision: D67615570
arhimondr
force-pushed
the
export-D67615570
branch
from
d634e88 to
ebd2e0b
Compare
arhimondr
changed the title
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
Summary: Prevent exchange client from unblocking to early. Unblocking to early impedes effectiveness of page merging. When the cost of creating a vector is high (for example for data sets with high number of columns) creating small pages can make queries significantly less efficient. For example it was observed that when network is congested and Exchange buffers are not filled up as fast query may experience CPU efficiency drop up to 4x: T211034421 Differential Revision: D67615570
arhimondr
force-pushed
the
export-D67615570
branch
from
ebd2e0b to
54f4247
Compare
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
arhimondr
force-pushed
the
export-D67615570
branch
from
54f4247 to
0c92f8b
Compare
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
arhimondr
force-pushed
the
export-D67615570
branch
from
0c92f8b to
8197447
Compare
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
arhimondr
force-pushed
the
export-D67615570
branch
from
8197447 to
6421f7d
Compare
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
arhimondr
force-pushed
the
export-D67615570
branch
from
6421f7d to
2631e22
Compare
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
arhimondr
force-pushed
the
export-D67615570
branch
from
2631e22 to
34fbab7
Compare
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
arhimondr
force-pushed
the
export-D67615570
branch
from
34fbab7 to
d82f1c8
Compare
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
arhimondr
force-pushed
the
export-D67615570
branch
from
d82f1c8 to
401586f
Compare
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
| @@ -52,6 +52,7 @@ Exchange::Exchange( | |||
| operatorCtx_->driverCtx()->queryConfig(), | |||
| serdeKind_)}, | |||
| processSplits_{operatorCtx_->driverCtx()->driverId == 0}, | |||
| driverId_{driverCtx->driverId}, | |||
There was a problem hiding this comment.
nit: we can just fetch from operatorCtx_->driverCtx()->driverId and not necessary save a copy of it.
There was a problem hiding this comment.
Just wanted to safe a couple of extra dereferences :-)
velox/exec/ExchangeQueue.h
Outdated
| uint32_t maxBytes, | ||
| bool* atEnd, | ||
| ContinueFuture* future, | ||
| std::vector<ContinuePromise>& promises); |
There was a problem hiding this comment.
s/promises/staledPromises/
Maybe put a comment? And at the caller, we expect it at most has one promise?
There was a problem hiding this comment.
Actually yeah, let me use a pointer instead of a list. It should never be more than one
Summary: Prevent exchange client from unblocking to early. Unblocking to early impedes effectiveness of page merging. When the cost of creating a vector is high (for example for data sets with high number of columns) creating small pages can make queries significantly less efficient. For example it was observed that when network is congested and Exchange buffers are not filled up as fast query may experience CPU efficiency drop up to 4x: T211034421 Reviewed By: xiaoxmeng Differential Revision: D67615570
arhimondr
force-pushed
the
export-D67615570
branch
from
401586f to
d263477
Compare
|
This pull request was exported from Phabricator. Differential Revision: D67615570 |
|
This pull request has been merged in 121b230. |
|
Conbench analyzed the 0 benchmark runs that triggered this notification. None of the specified runs were found on the Conbench server. The full Conbench report has more details. |
Summary:
Prevent exchange client from unblocking to early. Unblocking to early impedes
effectiveness of page merging. When the cost of creating a vector is high (for
example for data sets with high number of columns) creating small pages can
make queries significantly less efficient.
For example it was observed that when network is congested and Exchange buffers
are not filled up as fast query may experience CPU efficiency drop up to 4x: T211034421
Differential Revision: D67615570