I was asked for sending a reduced patchset
Would be good to explain what this reduced patchset is.
Complete patch contains this and that
Reduced patch contains only this.
Reduced patch contains:
* possibility to create and drop session variables (support for catalog pg_variable and related operations)
* possibility to set the session variable (command LET) and possibility to use session variable in the query
* access right support
* support for DISCARD command
* memory cleaning at transaction end when the variable is dropped
* warning when variable is shadowed by column
* introduction of variable's fences - syntax VARIABLE(varname)
Complete patch contains plus
* LET can be described by EXPLAIN
* LET can be prepared statement
* temporary session variables
* RESET at transaction end
* implementation of DEFAULT value for the variable
* implementation IMMUTABLE and NOT NULL clauses for the variable
* variable can be used as an argument of CALL statement (and doesn't block simple evaluation in plpgsql)
* used variable doesn't block with parallel execution
* LET from plpgsql can use simple expression evaluation (performance optimization for PL/pgSQL)
* variables doesn't block inlining SQL functions
* fix message "column doesn't exist" to "column or variable doesn't exist"
* support for transactional variables (content can be transactional)
* possibility to specify the name of restored variable for pg_restore
Regards
Pavel
