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5983a4cffc
The new compact_attrs array stores a few select fields from FormData_pg_attribute in a more compact way, using only 16 bytes per column instead of the 104 bytes that FormData_pg_attribute uses. Using CompactAttribute allows performance-critical operations such as tuple deformation to be performed without looking at the FormData_pg_attribute element in TupleDesc which means fewer cacheline accesses. For some workloads, tuple deformation can be the most CPU intensive part of processing the query. Some testing with 16 columns on a table where the first column is variable length showed around a 10% increase in transactions per second for an OLAP type query performing aggregation on the 16th column. However, in certain cases, the increases were much higher, up to ~25% on one AMD Zen4 machine. This also makes pg_attribute.attcacheoff redundant. A follow-on commit will remove it, thus shrinking the FormData_pg_attribute struct by 4 bytes. Author: David Rowley Reviewed-by: Andres Freund, Victor Yegorov Discussion: https://postgr.es/m/CAApHDvrBztXP3yx=NKNmo3xwFAFhEdyPnvrDg3=M0RhDs+4vYw@mail.gmail.com |
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| expected | ||
| sql | ||
| .gitignore | ||
| connection.c | ||
| deparse.c | ||
| Makefile | ||
| meson.build | ||
| option.c | ||
| postgres_fdw--1.1--1.2.sql | ||
| postgres_fdw--1.0--1.1.sql | ||
| postgres_fdw--1.0.sql | ||
| postgres_fdw.c | ||
| postgres_fdw.control | ||
| postgres_fdw.h | ||
| shippable.c | ||