Am 22.03.19 um 13:40 schrieb Francisco Olarte:
Thomas: On Fri, Mar 22, 2019 at 11:22 AM Thomas Güttler <guettliml@xxxxxxxxxxxxxxxxxx> wrote:Thank you for asking several times for a benchmark. I wrote it now and it is visible: inserting random bytes into bytea is much slower, if you use the psycopg2 defaults. Here is the chart: https://github.com/guettli/misc/blob/master/bench-bytea-inserts-postrgres.png And here is the script which creates the chart: https://github.com/guettli/misc/blob/master/bench-bytea-inserts-postrgres.pyI'm not too sure, but I read ( in the code ) you are measuring a nearly not compressible urandom data againtst a highly compressible ( 'x'*i ) data, are you sure the difference is not due to data being compressed and generating much less disk usage in toast-tables/wal?
+1 for this case toast-tables/wal is a detail of the implementation. This tests does not care about the "why it takes longer". It just generates a performance chart. Yes, it does exactly what you say: it compares nearly not compressible urandom data against a highly compressible data. In my case, will get nearly random data (binary PDF, JPG, ...). And that's why I wanted to benchmark it. Regards, Thomas -- Thomas Guettler http://www.thomas-guettler.de/ I am looking for feedback: https://github.com/guettli/programming-guidelines
