Contents
debug_print_rewritten
A GUC controlling whether the query rewriter output for a query is logged
debug_print_rewritten is a GUC controlling whether the query rewriter output for a query is logged.
debug_print_rewritten was added in PostgreSQL 7.1 (commit 6a68f426).
Default
Default value for debug_print_rewritten is: off
Notes
As far as it's possible to ascertain, debug_print_rewritten was added in feature commit (commit 6a68f426), in which PostgreSQL's Grand Unified Configuration system was introduced.
Examples
Sample output with an arbitrary query (here an INSERT into a partitioned table):
[2020-08-16 15:03:12 UTC] psql postgres postgres LOG: 00000: statement: INSERT INTO part_parent values(1,'foo') returning *;
[2020-08-16 15:03:12 UTC] psql postgres postgres LOCATION: exec_simple_query, postgres.c:1044
[2020-08-16 15:03:12 UTC] psql postgres postgres LOG: 00000: rewritten parse tree:
[2020-08-16 15:03:12 UTC] psql postgres postgres DETAIL: (
{QUERY
:commandType 3
:querySource 0
:canSetTag true
:utilityStmt <>
:resultRelation 1
:hasAggs false
:hasWindowFuncs false
:hasTargetSRFs false
:hasSubLinks false
:hasDistinctOn false
:hasRecursive false
:hasModifyingCTE false
:hasForUpdate false
:hasRowSecurity false
:cteList <>
:rtable (
{RTE
:alias <>
:eref
{ALIAS
:aliasname part_parent
:colnames ("id" "val")
}
:rtekind 0
:relid 16490
:relkind p
:rellockmode 3
:tablesample <>
:lateral false
:inh false
:inFromCl false
:requiredPerms 3
:checkAsUser 0
:selectedCols (b 8 9)
:insertedCols (b 8 9)
:updatedCols (b)
:extraUpdatedCols (b)
:securityQuals <>
}
)
:jointree
{FROMEXPR
:fromlist <>
:quals <>
}
:targetList (
{TARGETENTRY
:expr
{CONST
:consttype 23
:consttypmod -1
:constcollid 0
:constlen 4
:constbyval true
:constisnull false
:location 31
:constvalue 4 [ 1 0 0 0 0 0 0 0 ]
}
:resno 1
:resname id
:ressortgroupref 0
:resorigtbl 0
:resorigcol 0
:resjunk false
}
{TARGETENTRY
:expr
{FUNCEXPR
:funcid 669
:funcresulttype 1043
:funcretset false
:funcvariadic false
:funcformat 2
:funccollid 100
:inputcollid 100
:args (
{CONST
:consttype 1043
:consttypmod -1
:constcollid 100
:constlen -1
:constbyval false
:constisnull false
:location 33
:constvalue 7 [ 28 0 0 0 102 111 111 ]
}
{CONST
:consttype 23
:consttypmod -1
:constcollid 0
:constlen 4
:constbyval true
:constisnull false
:location -1
:constvalue 4 [ 36 0 0 0 0 0 0 0 ]
}
{CONST
:consttype 16
:consttypmod -1
:constcollid 0
:constlen 1
:constbyval true
:constisnull false
:location -1
:constvalue 1 [ 0 0 0 0 0 0 0 0 ]
}
)
:location -1
}
:resno 2
:resname val
:ressortgroupref 0
:resorigtbl 0
:resorigcol 0
:resjunk false
}
)
:override 0
:onConflict <>
:returningList (
{TARGETENTRY
:expr
{VAR
:varno 1
:varattno 1
:vartype 23
:vartypmod -1
:varcollid 0
:varlevelsup 0
:varnosyn 1
:varattnosyn 1
:location 51
}
:resno 1
:resname id
:ressortgroupref 0
:resorigtbl 16490
:resorigcol 1
:resjunk false
}
{TARGETENTRY
:expr
{VAR
:varno 1
:varattno 2
:vartype 1043
:vartypmod 36
:varcollid 100
:varlevelsup 0
:varnosyn 1
:varattnosyn 2
:location 51
}
:resno 2
:resname val
:ressortgroupref 0
:resorigtbl 16490
:resorigcol 2
:resjunk false
}
)
:groupClause <>
:groupingSets <>
:havingQual <>
:windowClause <>
:distinctClause <>
:sortClause <>
:limitOffset <>
:limitCount <>
:limitOption 0
:rowMarks <>
:setOperations <>
:constraintDeps <>
:withCheckOptions <>
:stmt_location 0
:stmt_len 52
}
)
[2020-08-16 15:03:12 UTC] psql postgres postgres LOCATION: elog_node_display, print.c:85
References
- PostgreSQL documentation: debug_print_rewritten