On Sat, 2020-05-16 at 20:12 -0500, Jack Christensen wrote: > I'm the creator of the PostgreSQL driver pgx (https://github.com/jackc/pgx) > for the Go language. > I have found significant performance advantages to using the extended > protocol and binary format > values -- in particular for types such as timestamptz. > > However, I was recently very surprised to find that it is significantly > slower to select a text > type value in the binary format. For an example case of selecting 1,000 rows > each with 5 text > columns of 16 bytes each the application time from sending the query to > having received the > entire response is approximately 16% slower. Here is a link to the test > benchmark: > https://github.com/jackc/pg_text_binary_bench > > Given that the text and binary formats for the text type are identical I > would not have > expected any performance differences. > > My C is rusty and my knowledge of the PG server internals is minimal but the > performance > difference appears to be that function textsend creates an extra copy where > textout > simply returns a pointer to the existing data. This seems to be superfluous. > > I can work around this by specifying the format per result column instead of > specifying > binary for all but this performance bug / anomaly seemed worth reporting.
Did you profile your benchmark? It would be interesting to know where the time is spent. Yours, Laurenz Albe
