Postgres 9.6升级后查询执行极其缓慢

Question

在Postgres从9.5升级到9.6之后，我看到了非常慢的处理时间，这与查询(用于处理OpenStreetMap数据的命令行Java应用程序)有关。特别是与主osm同步本地osm数据库(Postgis 2.3从2.2)。同步过去每天都会发生，平均花费大约500秒。经过升级，48小时后，它仍然没有结束。我注意到与以前相比，对象处理时间非常慢(低于零)(日志记录在下面)。我相当肯定问题在于Postgres的更新。不知道该修什么。pg_stat_activity提供以下查询(当前)：

UPDATE ways w 
SET linestring = ( 
    SELECT ST_MakeLine(c.geom) AS way_line 
    FROM ( 
        SELECT n.geom AS geom 
        FROM nodes n 
        INNER JOIN way_nodes wn ON n.id = wn.node_id 
        WHERE (wn.way_id = w.id) 
        ORDER BY wn.sequence_id ) c ) 
WHERE w.id IN ( 
    SELECT w.id 
    FROM ways w 
    INNER JOIN way_nodes wn ON w.id = wn.way_id 
    WHERE wn.node_id = $1 
    GROUP BY w.id ) 

更新后的日志记录：

Oct 31, 2017 12:23:59 PM org.openstreetmap.osmosis.core.Osmosis run
INFO: Osmosis Version 0.45
Oct 31, 2017 12:24:00 PM org.openstreetmap.osmosis.core.Osmosis run
INFO: Preparing pipeline.
Oct 31, 2017 12:24:00 PM org.openstreetmap.osmosis.core.Osmosis run
INFO: Launching pipeline execution.
Oct 31, 2017 12:24:00 PM org.openstreetmap.osmosis.core.Osmosis run
INFO: Pipeline executing, waiting for completion.
Oct 31, 2017 12:24:16 PM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 26022046 with action Modify, 0.06660006660006661 objects/second.
Oct 31, 2017 4:12:49 PM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 26022047 with action Modify, 7.292125918680253E-5 objects/second.
Oct 31, 2017 6:54:27 PM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 26022053 with action Modify, 1.0311411856040729E-4 objects/second.
Oct 31, 2017 9:39:22 PM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 26022056 with action Modify, 1.0106204077408672E-4 objects/second.
Nov 01, 2017 5:07:11 AM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 26022057 with action Modify, 3.72178939465691E-5 objects/second.
Nov 01, 2017 7:43:20 AM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 26022058 with action Modify, 1.0673723278600615E-4 objects/second.

更新前的日志记录：

Oct 22, 2017 11:00:01 PM org.openstreetmap.osmosis.core.Osmosis run
INFO: Osmosis Version 0.45
Oct 22, 2017 11:00:02 PM org.openstreetmap.osmosis.core.Osmosis run
INFO: Preparing pipeline.
Oct 22, 2017 11:00:02 PM org.openstreetmap.osmosis.core.Osmosis run
INFO: Launching pipeline execution.
Oct 22, 2017 11:00:02 PM org.openstreetmap.osmosis.core.Osmosis run
INFO: Pipeline executing, waiting for completion.
Oct 22, 2017 11:00:17 PM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 557521 with action Modify, 0.06700616456714018 objects/second.
Oct 22, 2017 11:00:22 PM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 49820266 with action Modify, 58.15347721822542 objects/second.
Oct 22, 2017 11:00:27 PM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 81804664 with action Modify, 40.64719810576164 objects/second.
Oct 22, 2017 11:00:32 PM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 109690032 with action Modify, 24.57577530719719 objects/second.
Oct 22, 2017 11:00:38 PM org.openstreetmap.osmosis.core.progress.v0_6.ChangeProgressLogger process
INFO: Processing Node 124684125 with action Modify, 58.35490938060148 objects/second.

Answer 1

FYI，我遇到了完全相同的问题:我将pg从9.4升级到9.6，查询速度要慢得多。

我只运行真空，没有什么改变，但我运行分析，如@harmic建议，现在运行良好(更快，由于第9.6页的改进: )！

Answer 2

在Postgres升级之后，您需要分析数据库以便快速查询平面。

若要分析完整的数据库，请运行以下查询

ANALYZE VERBOSE  --for all database analyze 

仅分析特定表，然后使用此查询

ANALYZE VERBOSE  [Table_name] --for particular table

查询在此支持的版本中工作:当前(13) / 12 / 11 / 10 / 9.6 / 9.5

参考资料：https://www.postgresql.org/docs/9.1/sql-analyze.html