Commit5763ef4

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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
`@@ -203,6 +203,7 @@ struct NumericData`
`203`	`203`	`*/`
`204`	`204`
`205`	`205`	`#defineNUMERIC_DSCALE_MASK0x3FFF`
	`206`	`+#defineNUMERIC_DSCALE_MAXNUMERIC_DSCALE_MASK`
`206`	`207`
`207`	`208`	`#defineNUMERIC_SIGN(n) \`
`208`	`209`	`(NUMERIC_IS_SHORT(n) ? \`
`@@ -2488,14 +2489,21 @@ numeric_mul(PG_FUNCTION_ARGS)`
`2488`	`2489`	`* Unlike add_var() and sub_var(), mul_var() will round its result. In the`
`2489`	`2490`	`* case of numeric_mul(), which is invoked for the * operator on numerics,`
`2490`	`2491`	`* we request exact representation for the product (rscale = sum(dscale of`
`2491`		`- * arg1, dscale of arg2)).`
	`2492`	`+ * arg1, dscale of arg2)). If the exact result has more digits after the`
	`2493`	`+ * decimal point than can be stored in a numeric, we round it. Rounding`
	`2494`	`+ * after computing the exact result ensures that the final result is`
	`2495`	`+ * correctly rounded (rounding in mul_var() using a truncated product`
	`2496`	`+ * would not guarantee this).`
`2492`	`2497`	`*/`
`2493`	`2498`	`init_var_from_num(num1,&arg1);`
`2494`	`2499`	`init_var_from_num(num2,&arg2);`
`2495`	`2500`
`2496`	`2501`	`init_var(&result);`
`2497`	`2502`	`mul_var(&arg1,&arg2,&result,arg1.dscale+arg2.dscale);`
`2498`	`2503`
	`2504`	`+if (result.dscale>NUMERIC_DSCALE_MAX)`
	`2505`	`+round_var(&result,NUMERIC_DSCALE_MAX);`
	`2506`	`+`
`2499`	`2507`	`res=make_result(&result);`
`2500`	`2508`
`2501`	`2509`	`free_var(&result);`

Lines changed: 6 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -1498,6 +1498,12 @@ select 4769999999999999999999999999999999999999999999999999999999999999999999999`
`1498`	`1498`	`47699999999999999999999999999999999999999999999999999999999999999999999999999999999999985230000000000000000000000000000000000000000000000000000000000000000000000000000000000001`
`1499`	`1499`	`(1 row)`
`1500`	`1500`
	`1501`	`+select (0.1 - 2e-16383) * (0.1 - 3e-16383) = 0.01 as rounds_to_point_zero_one;`
	`1502`	`+ rounds_to_point_zero_one`
	`1503`	`+--------------------------`
	`1504`	`+ t`
	`1505`	`+(1 row)`
	`1506`	`+`
`1501`	`1507`	`--`
`1502`	`1508`	`-- Test some corner cases for division`
`1503`	`1509`	`--`

Lines changed: 2 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -864,6 +864,8 @@ select 4770999999999999999999999999999999999999999999999999999999999999999999999`
`864`	`864`
`865`	`865`	`select4769999999999999999999999999999999999999999999999999999999999999999999999999999999999999*9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;`
`866`	`866`
	`867`	`+select (0.1- 2e-16383)* (0.1- 3e-16383)=0.01as rounds_to_point_zero_one;`
	`868`	`+`
`867`	`869`	`--`
`868`	`870`	`-- Test some corner cases for division`
`869`	`871`	`--`

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