enhance: avoid too many gorountines when calc distance

[CocaineCong]

use gorountines pool to avoid too many gorountines be created.

[sre-ci-robot]

Welcome @CocaineCong! It looks like this is your first PR to milvus-io/milvus 🎉

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: CocaineCong To complete the pull request process, please assign czs007 after the PR has been reviewed. You can assign the PR to them by writing /assign @czs007 in a comment when ready.

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• pkg/util/OWNERS

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[mergify[bot]]

@CocaineCong Thanks for your contribution. Please submit with DCO, see the contributing guide https://github.com/milvus-io/milvus/blob/master/CONTRIBUTING.md#developer-certificate-of-origin-dco.

[mergify[bot]]

@CocaineCong

Invalid PR Title Format Detected

Your PR submission does not adhere to our required standards. To ensure clarity and consistency, please meet the following criteria:

1. Title Format: The PR title must begin with one of these prefixes:

• feat: for introducing a new feature.
• fix: for bug fixes.
• enhance: for improvements to existing functionality.
• test: for add tests to existing functionality.
• doc: for modifying documentation.
• auto: for the pull request from bot.

2. Description Requirement: The PR must include a non-empty description, detailing the changes and their impact.

Required Title Structure:

[Type]: [Description of the PR]

Where Type is one of feat, fix, enhance, test or doc.

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enhance: improve search performance significantly 

Please review and update your PR to comply with these guidelines.

[mergify[bot]]

@CocaineCong E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[SimFG]

@CocaineCong thanks your contribution. you need to have a sign for the commit to pass the dco check. try to do:

git commit --amend -s

and then force to push it

[mergify[bot]]

@CocaineCong ut workflow job failed, comment rerun ut can trigger the job again.

[CocaineCong]

@SimFG ok, finished! thanks u so much and PTAL.

[CocaineCong]

rerun ut

[github-actions[bot]]

Hello CocaineCong, you are not in the organization, so you do not have the permission to rerun the workflow, please contact @milvus-io/milvus-maintainers for help.

[SimFG]

rerun ut