Re: Poor performance PostgreSQL 13/ PostGIS 3.x

On Thu, Jan 20, 2022 at 4:50 PM Lugosi, Jim <JimLug(at)clackamas(dot)us> wrote:
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> Hi folks,
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>
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> We are struggling to figure out what is going on. We are migrating from PostgreSQL 9.6 to PostgreSQL 13 w/ PostGIS. Our 9.6 version was compiled from source and the new version (13) was installed using Yum. BTW, the new version is on a VM that has 16GB of memory, two cores, and 500 GB of disk. In addition, we are using MapServer as our mapping engine and OpenLayers as the client side interface. Once we switch over to the new version of PostgreSQL, the performance takes a big nose dive. We have being tweaking and tuning the database and it appears to be happy but the response times from mapfile requests are 3 -7 seconds. Previously, the response time was below a second.

please post EXPLAIN ANALYZE for a query that you think is
underperforming. Ideally, we can also produce from legacy 9.6
equivalent.

merlin