the Postgresql version is 13.6 and the DECLARE COMMAND IS declare sdx_3a6c_8 no scroll binary cursor without hold for select "roalkL"."smid","roalkL"."smgeometry" from "public"."roalkL" where "roalkL"."smgeometry" && st_makeenvelope(321673.3153346270555630,3375950.6560412631370127,367212.1915803211741149,3402758.1912380573339760,32649)
the data might be 1GB,and we need get all in about 10 seconds. Adrian Klaver <adrian.kla...@aklaver.com> 于2023年4月14日周五 23:11写道： > On 4/14/23 04:04, 黄宁 wrote: > > i want to use cursor with hold ,but when I declare a curosr , it takes a > > long time to save the result set to disk. can i save the query state in > > memory? and fetch forward the next result. > > > > From the docs: > > https://www.postgresql.org/docs/current/sql-declare.html > > A cursor created with WITH HOLD is closed when an explicit CLOSE command > is issued on it, or the session ends. In the current implementation, the > rows represented by a held cursor are copied into a temporary file or > memory area so that they remain available for subsequent transactions. > > So I am going to guess the cursor query is holding a large amount of data. > > To get a more specific answer you will need to provide: > > 1) Postgres version. > > 2) The complete DECLARE command being used. > > 3) An indication of the amount of data being retrieved. > > 4) The actual time for a 'long time'. > > -- > Adrian Klaver > adrian.kla...@aklaver.com > >
