Commite7fc488

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Fix numeric_mul() overflow due to too many digits after decimal point.

This fixes an overflow error when using the numeric * operator if theresult has more than 16383 digits after the decimal point by roundingthe result. Overflow errors should only occur if the result has toomany digits *before* the decimal point.Discussion:https://postgr.es/m/CAEZATCUmeFWCrq2dNzZpRj5+6LfN85jYiDoqm+ucSXhb9U2TbA@mail.gmail.com

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Lines changed: 9 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -233,6 +233,7 @@ struct NumericData`
`233`	`233`	`*/`
`234`	`234`
`235`	`235`	`#defineNUMERIC_DSCALE_MASK0x3FFF`
	`236`	`+#defineNUMERIC_DSCALE_MAXNUMERIC_DSCALE_MASK`
`236`	`237`
`237`	`238`	`#defineNUMERIC_SIGN(n) \`
`238`	`239`	`(NUMERIC_IS_SHORT(n) ? \`
`@@ -2958,14 +2959,21 @@ numeric_mul_opt_error(Numeric num1, Numeric num2, bool *have_error)`
`2958`	`2959`	`* Unlike add_var() and sub_var(), mul_var() will round its result. In the`
`2959`	`2960`	`* case of numeric_mul(), which is invoked for the * operator on numerics,`
`2960`	`2961`	`* we request exact representation for the product (rscale = sum(dscale of`
`2961`		`- * arg1, dscale of arg2)).`
	`2962`	`+ * arg1, dscale of arg2)). If the exact result has more digits after the`
	`2963`	`+ * decimal point than can be stored in a numeric, we round it. Rounding`
	`2964`	`+ * after computing the exact result ensures that the final result is`
	`2965`	`+ * correctly rounded (rounding in mul_var() using a truncated product`
	`2966`	`+ * would not guarantee this).`
`2962`	`2967`	`*/`
`2963`	`2968`	`init_var_from_num(num1,&arg1);`
`2964`	`2969`	`init_var_from_num(num2,&arg2);`
`2965`	`2970`
`2966`	`2971`	`init_var(&result);`
`2967`	`2972`	`mul_var(&arg1,&arg2,&result,arg1.dscale+arg2.dscale);`
`2968`	`2973`
	`2974`	`+if (result.dscale>NUMERIC_DSCALE_MAX)`
	`2975`	`+round_var(&result,NUMERIC_DSCALE_MAX);`
	`2976`	`+`
`2969`	`2977`	`res=make_result_opt_error(&result,have_error);`
`2970`	`2978`
`2971`	`2979`	`free_var(&result);`

Lines changed: 6 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -2145,6 +2145,12 @@ select 4769999999999999999999999999999999999999999999999999999999999999999999999`
`2145`	`2145`	`47699999999999999999999999999999999999999999999999999999999999999999999999999999999999985230000000000000000000000000000000000000000000000000000000000000000000000000000000000001`
`2146`	`2146`	`(1 row)`
`2147`	`2147`
	`2148`	`+select trim_scale((0.1 - 2e-16383) * (0.1 - 3e-16383));`
	`2149`	`+ trim_scale`
	`2150`	`+------------`
	`2151`	`+ 0.01`
	`2152`	`+(1 row)`
	`2153`	`+`
`2148`	`2154`	`--`
`2149`	`2155`	`-- Test some corner cases for division`
`2150`	`2156`	`--`

Lines changed: 2 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -1044,6 +1044,8 @@ select 4770999999999999999999999999999999999999999999999999999999999999999999999`
`1044`	`1044`
`1045`	`1045`	`select4769999999999999999999999999999999999999999999999999999999999999999999999999999999999999*9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;`
`1046`	`1046`
	`1047`	`+select trim_scale((0.1- 2e-16383)* (0.1- 3e-16383));`
	`1048`	`+`
`1047`	`1049`	`--`
`1048`	`1050`	`-- Test some corner cases for division`
`1049`	`1051`	`--`

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