|
8 | 8 | * |
9 | 9 | * |
10 | 10 | * IDENTIFICATION |
11 | | - * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.148 2003/07/28 18:33:18 tgl Exp $ |
| 11 | + * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.149 2003/08/03 23:46:37 tgl Exp $ |
12 | 12 | * |
13 | 13 | * HISTORY |
14 | 14 | * AUTHORDATEMAJOR EVENT |
|
26 | 26 | #include"miscadmin.h" |
27 | 27 | #include"nodes/makefuncs.h" |
28 | 28 | #include"optimizer/clauses.h" |
| 29 | +#include"optimizer/cost.h" |
29 | 30 | #include"optimizer/planmain.h" |
30 | 31 | #include"optimizer/var.h" |
31 | 32 | #include"parser/analyze.h" |
@@ -1710,8 +1711,12 @@ evaluate_function(Oid funcid, Oid result_type, List *args, |
1710 | 1711 | * so we keep track of which functions we are already expanding and |
1711 | 1712 | * do not re-expand them. Also, if a parameter is used more than once |
1712 | 1713 | * in the SQL-function body, we require it not to contain any volatile |
1713 | | - * functions or sublinks --- volatiles might deliver inconsistent answers, |
1714 | | - * and subplans might be unreasonably expensive to evaluate multiple times. |
| 1714 | + * functions (volatiles might deliver inconsistent answers) nor to be |
| 1715 | + * unreasonably expensive to evaluate. The expensiveness check not only |
| 1716 | + * prevents us from doing multiple evaluations of an expensive parameter |
| 1717 | + * at runtime, but is a safety value to limit growth of an expression due |
| 1718 | + * to repeated inlining. |
| 1719 | + * |
1715 | 1720 | * We must also beware of changing the volatility or strictness status of |
1716 | 1721 | * functions by inlining them. |
1717 | 1722 | * |
@@ -1912,9 +1917,26 @@ inline_function(Oid funcid, Oid result_type, List *args, |
1912 | 1917 | } |
1913 | 1918 | elseif (usecounts[i]!=1) |
1914 | 1919 | { |
1915 | | -/* Param used multiple times: uncool if volatile or expensive */ |
1916 | | -if (contain_volatile_functions(param)|| |
1917 | | -contain_subplans(param)) |
| 1920 | +/* Param used multiple times: uncool if expensive or volatile */ |
| 1921 | +QualCosteval_cost; |
| 1922 | + |
| 1923 | +/* |
| 1924 | + * We define "expensive" as "contains any subplan or more than |
| 1925 | + * 10 operators". Note that the subplan search has to be done |
| 1926 | + * explicitly, since cost_qual_eval() will barf on unplanned |
| 1927 | + * subselects. |
| 1928 | + */ |
| 1929 | +if (contain_subplans(param)) |
| 1930 | +gotofail; |
| 1931 | +cost_qual_eval(&eval_cost,makeList1(param)); |
| 1932 | +if (eval_cost.startup+eval_cost.per_tuple> |
| 1933 | +10*cpu_operator_cost) |
| 1934 | +gotofail; |
| 1935 | +/* |
| 1936 | + * Check volatility last since this is more expensive than the |
| 1937 | + * above tests |
| 1938 | + */ |
| 1939 | +if (contain_volatile_functions(param)) |
1918 | 1940 | gotofail; |
1919 | 1941 | } |
1920 | 1942 | i++; |
|