mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2025-01-18 18:44:06 +08:00
Code Issues Packages Projects Releases Wiki Activity

Don't lose precision for float fields of Nodes.

Browse Source 
Historically we've been more worried about making the output of
float fields look pretty than whether they'd be read back exactly.
That won't work if we're to compare the read-back nodes for
equality, so switch to using the Ryu code for float output.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/4159834.1657405226@sss.pgh.pa.us
This commit is contained in:
Peter Eisentraut 2022-09-26 16:02:09 +02:00
parent c07785d458
commit acd624644b
2 changed files with 25 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
src/backend/nodes/gen_node_support.pl
View File

@ -983,29 +983,29 @@ _read${n}(void)
}
elsif ($t eq 'double')
{
print $off "\tWRITE_FLOAT_FIELD($f, \"%.6f\");\n";
print $off "\tWRITE_FLOAT_FIELD($f);\n";
print $rff "\tREAD_FLOAT_FIELD($f);\n" unless $no_read;
}
elsif ($t eq 'Cardinality')
{
print $off "\tWRITE_FLOAT_FIELD($f, \"%.0f\");\n";
print $off "\tWRITE_FLOAT_FIELD($f);\n";
print $rff "\tREAD_FLOAT_FIELD($f);\n" unless $no_read;
}
elsif ($t eq 'Cost')
{
print $off "\tWRITE_FLOAT_FIELD($f, \"%.2f\");\n";
print $off "\tWRITE_FLOAT_FIELD($f);\n";
print $rff "\tREAD_FLOAT_FIELD($f);\n" unless $no_read;
}
elsif ($t eq 'QualCost')
{
print $off "\tWRITE_FLOAT_FIELD($f.startup, \"%.2f\");\n";
print $off "\tWRITE_FLOAT_FIELD($f.per_tuple, \"%.2f\");\n";
print $off "\tWRITE_FLOAT_FIELD($f.startup);\n";
print $off "\tWRITE_FLOAT_FIELD($f.per_tuple);\n";
print $rff "\tREAD_FLOAT_FIELD($f.startup);\n" unless $no_read;
print $rff "\tREAD_FLOAT_FIELD($f.per_tuple);\n" unless $no_read;
}
elsif ($t eq 'Selectivity')
{
print $off "\tWRITE_FLOAT_FIELD($f, \"%.4f\");\n";
print $off "\tWRITE_FLOAT_FIELD($f);\n";
print $rff "\tREAD_FLOAT_FIELD($f);\n" unless $no_read;
}
elsif ($t eq 'char*')

23
src/backend/nodes/outfuncs.c
View File

@ -17,6 +17,7 @@
#include <ctype.h>
#include "access/attnum.h"
#include "common/shortest_dec.h"
#include "lib/stringinfo.h"
#include "miscadmin.h"
#include "nodes/bitmapset.h"
@ -25,6 +26,7 @@
#include "utils/datum.h"
static void outChar(StringInfo str, char c);
static void outDouble(StringInfo str, double d);
/*
@ -69,9 +71,10 @@ static void outChar(StringInfo str, char c);
appendStringInfo(str, " :" CppAsString(fldname) " %d", \
(int) node->fldname)
/* Write a float field --- caller must give format to define precision */
#define WRITE_FLOAT_FIELD(fldname,format) \
appendStringInfo(str, " :" CppAsString(fldname) " " format, node->fldname)
/* Write a float field (actually, they're double) */
#define WRITE_FLOAT_FIELD(fldname) \
(appendStringInfo(str, " :" CppAsString(fldname) " "), \
outDouble(str, node->fldname))
/* Write a boolean field */
#define WRITE_BOOL_FIELD(fldname) \
@ -198,6 +201,18 @@ outChar(StringInfo str, char c)
outToken(str, in);
}
/*
* Convert a double value, attempting to ensure the value is preserved exactly.
*/
static void
outDouble(StringInfo str, double d)
{
char buf[DOUBLE_SHORTEST_DECIMAL_LEN];
double_to_shortest_decimal_buf(d, buf);
appendStringInfoString(str, buf);
}
/*
* common implementation for scalar-array-writing functions
*
@ -525,7 +540,7 @@ _outRangeTblEntry(StringInfo str, const RangeTblEntry *node)
break;
case RTE_NAMEDTUPLESTORE:
WRITE_STRING_FIELD(enrname);
WRITE_FLOAT_FIELD(enrtuples, "%.0f");
WRITE_FLOAT_FIELD(enrtuples);
WRITE_OID_FIELD(relid);
WRITE_NODE_FIELD(coltypes);
WRITE_NODE_FIELD(coltypmods);