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Adjust fetch size on queries #2097
Description
Hi, we are suffereing from hight ClientWaits and one thing we would like to try is to make the fetch size bigger when we receive many results from the query. I cannot find anything related to this in the docs or the code (to be honest I have to dig deeper yet), is there any way to play with this value?
Am I right to assume this rows (https://github.com/brianc/node-postgres/blob/master/packages/pg/lib/query.js#L27) config defined the amount of rows to fetch by the cursor each time? I dont find docs around this
Activity
brianc commentedon Feb 4, 2020
glena commentedon Feb 4, 2020
I am talking about the analogous to this JDBC configuration. At this point we are running out of ideas and experimenting with a setting as such will help us to tune or discard the hypothesis
https://medium.com/@FranckPachot/oracle-postgres-jdbc-fetch-size-3012d494712
brianc commentedon Feb 4, 2020
glena commentedon Feb 7, 2020
I have being playing with this and works as expected (probably is worth documenting). PG will split the results into batches of x rows which helps avoiding flooding the consumer on large result-sets (or unbounded queries). It is not helping our particular case as we were under the assumption that by default it will use a small batch (as the java driver does) but turns out it just gets everything from one transfer.
I could not test fast-connection yet, what is the current status? is it production ready or you are still polishing out?
what is the main differences between both?
Thank you!
siddhsql commentedon May 6, 2023
ping. same question here. does this library have anything analogous to jdbc setfetchsize? ref: https://stackoverflow.com/questions/1318354/what-does-statement-setfetchsizensize-method-really-do-in-sql-server-jdbc-driv
proddata commentedon May 8, 2023
You can use a Cursor which afaik is eqv: https://node-postgres.com/apis/cursor
JDBC Fetch Size afaik also uses the extended queries and server side cursors/portals:
https://www.postgresql.org/docs/current/protocol-flow.html#PROTOCOL-FLOW-EXT-QUERY
brianc commentedon May 8, 2023