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postgres - 如何在使用 order by 扫描查询时跳过分区

[英]postgres - how to skip partitions when scanning query with order by

原文 2022-08-30 18:40:14 2 1 postgresql/ postgresql-11

I'm trying to query a postgres partitioned by range table with order by and limit.我正在尝试使用 order by 和 limit 查询由范围表分区的 postgres。 Is there a way to make it scan partitions by order and skip the rest of partitions after it reached the limit of 20?有没有办法让它按顺序扫描分区并在达到20个限制后跳过分区的rest？ (using postgres 11.3 but can upgrade if necessary) （使用 postgres 11.3 但必要时可以升级）

SELECT * FROM table ORDER BY timestamp DESC LIMIT 20 SELECT * FROM table ORDER BY timestamp DESC LIMIT 20

1 个解决方案

Not in v11.不在 v11 中。

This will work automatically provided you have an index starting with "timestamp", and you upgrade to at least v12.如果您有一个以“timestamp”开头的索引，并且您至少升级到 v12，这将自动工作。

It seems like this could work without the index (sorting each partition in turn, starting at the proper end of the range, until it gets its LIMIT), but I guess no one bothered to implement that.似乎这可以在没有索引的情况下工作（依次对每个分区进行排序，从范围的正确末端开始，直到它得到它的 LIMIT），但我想没有人会费心去实现它。

分区表查询仍然扫描所有分区 - Partitioned table query still scanning all partitions

Postgres-如何合并分区？ - Postgres - how to merge partitions?

¿ Postgres 窗口的 function 在分区中使用 order by 时是否执行隐式过滤？ - ¿Does Postgres window's function performs an implicit filtering when using order by in the partitions?

如何在ActiveRecord Postgres查询中对分组的列进行排序 - How to order grouped columns in an ActiveRecord Postgres query

如何在 postgres 中按自定义日期格式的顺序查询？ - How to query in order of custom date format in postgres?

在postgres中的递归查询中排序 - Order by in a recursive query in postgres

Postgres 中有多少表分区太多了？ - How many table partitions is too many in Postgres?

在 postgres 中按查询执行 where 和 order by 时的奇怪行为 - Strange behavior when doing where and order by query in postgres

在 postgres 查询中使用 ANY 时，有没有办法保留顺序或数组？ - is there a way to preserve order or array when using ANY in postgres query?

当没有提供ORDER BY时，postgres如何订购结果 - How does postgres order the results when ORDER BY is not provided

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