Performance consequence of leftOuterJoinLateral

[Rex Fenley]

Hello,

I'm curious if there's any performance consequence of using a TableFunction + leftOuterJoinLateral to create some new columns vs creating each column individually?

I'm hoping that lookup for a row with leftOuterJoinLateral is essentially O(1), so as soon as the TableFunction is done it just appends the new column values to the row.

Thanks!

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[Danny Chan-2]

Hi, Rex ~

For "leftOuterJoinLateral" do you mean join a table function through lateral table ?

If it is, yes, the complexity is O(1) for each probe key of LHS. The table function evaluate the extra columns and append it to the left columns.

Rex Fenley <[hidden email]> 于2020年12月2日周三 上午7:54写道：

Hello,

I'm curious if there's any performance consequence of using a TableFunction + leftOuterJoinLateral to create some new columns vs creating each column individually?

I'm hoping that lookup for a row with leftOuterJoinLateral is essentially O(1), so as soon as the TableFunction is done it just appends the new column values to the row.

Thanks!

--

Rex Fenley  |  Software Engineer - Mobile and Backend

Remind.com |  BLOG  |  FOLLOW US  |  LIKE US

[Rex Fenley]

Yes, exactly. Thanks!

On Tue, Dec 1, 2020 at 6:11 PM Danny Chan <[hidden email]> wrote:

Hi, Rex ~

For "leftOuterJoinLateral" do you mean join a table function through lateral table ?

If it is, yes, the complexity is O(1) for each probe key of LHS. The table function evaluate the extra columns and append it to the left columns.

Rex Fenley <[hidden email]> 于2020年12月2日周三 上午7:54写道：

Hello,

I'm curious if there's any performance consequence of using a TableFunction + leftOuterJoinLateral to create some new columns vs creating each column individually?

I'm hoping that lookup for a row with leftOuterJoinLateral is essentially O(1), so as soon as the TableFunction is done it just appends the new column values to the row.

Thanks!

--

Rex Fenley  |  Software Engineer - Mobile and Backend

Remind.com |  BLOG  |  FOLLOW US  |  LIKE US

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