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Improve plpgsql's handling of record field references by forcing all potential 

field references in SQL expressions to have RECFIELD datum-array entries at
parse time.  If it turns out that the reference is actually to a SQL column,
the RECFIELD entry is useless, but it costs little.  This allows us to get rid
of the previous use of FieldSelect applied to a whole-row Param for the record
variable; which was not only slower than a direct RECFIELD reference, but
failed for references to system columns of a trigger's NEW or OLD record.
Per report and fix suggestion from Dean Rasheed.
This commit is contained in:
Tom Lane 2010-01-10 17:15:18 +00:00
parent f537e7dfa4
commit 01f7d29902
4 changed files with 77 additions and 74 deletions
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38
src/pl/plpgsql/src/gram.y
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.137 2010/01/02 16:58:12 momjian Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.138 2010/01/10 17:15:18 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -369,21 +369,21 @@ pl_block : decl_sect K_BEGIN proc_sect exception_sect K_END opt_label
decl_sect : opt_block_label
{
/* done with decls, so resume identifier lookup */
plpgsql_LookupIdentifiers = true;
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_NORMAL;
$$.label = $1;
$$.n_initvars = 0;
$$.initvarnos = NULL;
}
| opt_block_label decl_start
{
plpgsql_LookupIdentifiers = true;
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_NORMAL;
$$.label = $1;
$$.n_initvars = 0;
$$.initvarnos = NULL;
}
| opt_block_label decl_start decl_stmts
{
plpgsql_LookupIdentifiers = true;
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_NORMAL;
if ($3 != NULL)
$$.label = $3;
else
@ -401,7 +401,7 @@ decl_start : K_DECLARE
* Disable scanner lookup of identifiers while
* we process the decl_stmts
*/
plpgsql_LookupIdentifiers = false;
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_DECLARE;
}
;
@ -2121,7 +2121,7 @@ read_sql_construct(int until,
{
int tok;
StringInfoData ds;
bool save_LookupIdentifiers;
IdentifierLookup save_IdentifierLookup;
int startlocation = -1;
int parenlevel = 0;
PLpgSQL_expr *expr;
@ -2129,9 +2129,9 @@ read_sql_construct(int until,
initStringInfo(&ds);
appendStringInfoString(&ds, sqlstart);
/* no need to lookup identifiers within the SQL text */
save_LookupIdentifiers = plpgsql_LookupIdentifiers;
plpgsql_LookupIdentifiers = false;
/* special lookup mode for identifiers within the SQL text */
save_IdentifierLookup = plpgsql_IdentifierLookup;
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_EXPR;
for (;;)
{
@ -2176,7 +2176,7 @@ read_sql_construct(int until,
}
}
plpgsql_LookupIdentifiers = save_LookupIdentifiers;
plpgsql_IdentifierLookup = save_IdentifierLookup;
if (startloc)
*startloc = startlocation;
@ -2221,8 +2221,8 @@ read_datatype(int tok)
PLpgSQL_type *result;
int parenlevel = 0;
/* Should always be called with LookupIdentifiers off */
Assert(!plpgsql_LookupIdentifiers);
/* Should only be called while parsing DECLARE sections */
Assert(plpgsql_IdentifierLookup == IDENTIFIER_LOOKUP_DECLARE);
/* Often there will be a lookahead token, but if not, get one */
if (tok == YYEMPTY)
@ -2327,7 +2327,7 @@ static PLpgSQL_stmt *
make_execsql_stmt(int firsttoken, int location)
{
StringInfoData ds;
bool save_LookupIdentifiers;
IdentifierLookup save_IdentifierLookup;
PLpgSQL_stmt_execsql *execsql;
PLpgSQL_expr *expr;
PLpgSQL_row *row = NULL;
@ -2341,9 +2341,9 @@ make_execsql_stmt(int firsttoken, int location)
initStringInfo(&ds);
/* no need to lookup identifiers within the SQL text */
save_LookupIdentifiers = plpgsql_LookupIdentifiers;
plpgsql_LookupIdentifiers = false;
/* special lookup mode for identifiers within the SQL text */
save_IdentifierLookup = plpgsql_IdentifierLookup;
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_EXPR;
/*
* We have to special-case the sequence INSERT INTO, because we don't want
@ -2371,13 +2371,13 @@ make_execsql_stmt(int firsttoken, int location)
yyerror("INTO specified more than once");
have_into = true;
into_start_loc = yylloc;
plpgsql_LookupIdentifiers = true;
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_NORMAL;
read_into_target(&rec, &row, &have_strict);
plpgsql_LookupIdentifiers = false;
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_EXPR;
}
}
plpgsql_LookupIdentifiers = save_LookupIdentifiers;
plpgsql_IdentifierLookup = save_IdentifierLookup;
if (have_into)
{

86
src/pl/plpgsql/src/pl_comp.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.147 2010/01/02 16:58:12 momjian Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.148 2010/01/10 17:15:18 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1132,11 +1132,7 @@ resolve_column_ref(PLpgSQL_expr *expr, ColumnRef *cref)
return make_datum_param(expr, nse->itemno, cref->location);
if (nnames == nnames_field)
{
/* colname must be a field in this record */
PLpgSQL_rec *rec = (PLpgSQL_rec *) estate->datums[nse->itemno];
FieldSelect *fselect;
Oid fldtype;
int fldno;
/* colname could be a field in this record */
int i;
/* search for a datum referencing this field */
@ -1153,20 +1149,11 @@ resolve_column_ref(PLpgSQL_expr *expr, ColumnRef *cref)
}
/*
* We can't readily add a recfield datum at runtime, so
* instead build a whole-row Param and a FieldSelect node.
* This is a bit less efficient, so we prefer the recfield
* way when possible.
* We should not get here, because a RECFIELD datum should
* have been built at parse time for every possible qualified
* reference to fields of this record. But if we do, fall
* out and return NULL.
*/
fldtype = exec_get_rec_fieldtype(rec, colname,
&fldno);
fselect = makeNode(FieldSelect);
fselect->arg = (Expr *) make_datum_param(expr, nse->itemno,
cref->location);
fselect->fieldnum = fldno;
fselect->resulttype = fldtype;
fselect->resulttypmod = -1;
return (Node *) fselect;
}
break;
case PLPGSQL_NSTYPE_ROW:
@ -1174,7 +1161,7 @@ resolve_column_ref(PLpgSQL_expr *expr, ColumnRef *cref)
return make_datum_param(expr, nse->itemno, cref->location);
if (nnames == nnames_field)
{
/* colname must be a field in this row */
/* colname could be a field in this row */
PLpgSQL_row *row = (PLpgSQL_row *) estate->datums[nse->itemno];
int i;
@ -1187,10 +1174,7 @@ resolve_column_ref(PLpgSQL_expr *expr, ColumnRef *cref)
cref->location);
}
}
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("row \"%s\" has no field \"%s\"",
row->refname, colname)));
/* Not found, so return NULL */
}
break;
default:
@ -1257,8 +1241,12 @@ plpgsql_parse_word(char *word1, const char *yytxt,
{
PLpgSQL_nsitem *ns;
/* No lookup if disabled */
if (plpgsql_LookupIdentifiers)
/*
* We should do nothing in DECLARE sections. In SQL expressions, there's
* no need to do anything either --- lookup will happen when the expression
* is compiled.
*/
if (plpgsql_IdentifierLookup == IDENTIFIER_LOOKUP_NORMAL)
{
/*
* Do a lookup in the current namespace stack
@ -1281,6 +1269,7 @@ plpgsql_parse_word(char *word1, const char *yytxt,
return true;
default:
/* plpgsql_ns_lookup should never return anything else */
elog(ERROR, "unrecognized plpgsql itemtype: %d",
ns->itemtype);
}
@ -1313,8 +1302,12 @@ plpgsql_parse_dblword(char *word1, char *word2,
idents = list_make2(makeString(word1),
makeString(word2));
/* No lookup if disabled */
if (plpgsql_LookupIdentifiers)
/*
* We should do nothing in DECLARE sections. In SQL expressions,
* we really only need to make sure that RECFIELD datums are created
* when needed.
*/
if (plpgsql_IdentifierLookup != IDENTIFIER_LOOKUP_DECLARE)
{
/*
* Do a lookup in the current namespace stack
@ -1338,8 +1331,10 @@ plpgsql_parse_dblword(char *word1, char *word2,
if (nnames == 1)
{
/*
* First word is a record name, so second word must be
* a field in this record.
* First word is a record name, so second word could
* be a field in this record. We build a RECFIELD
* datum whether it is or not --- any error will be
* detected later.
*/
PLpgSQL_recfield *new;
@ -1366,8 +1361,9 @@ plpgsql_parse_dblword(char *word1, char *word2,
if (nnames == 1)
{
/*
* First word is a row name, so second word must be a
* field in this row.
* First word is a row name, so second word could be
* a field in this row. Again, no error now if it
* isn't.
*/
PLpgSQL_row *row;
int i;
@ -1385,10 +1381,7 @@ plpgsql_parse_dblword(char *word1, char *word2,
return true;
}
}
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("row \"%s\" has no field \"%s\"",
word1, word2)));
/* fall through to return CWORD */
}
else
{
@ -1399,6 +1392,7 @@ plpgsql_parse_dblword(char *word1, char *word2,
wdatum->idents = idents;
return true;
}
break;
default:
break;
@ -1429,8 +1423,12 @@ plpgsql_parse_tripword(char *word1, char *word2, char *word3,
makeString(word2),
makeString(word3));
/* No lookup if disabled */
if (plpgsql_LookupIdentifiers)
/*
* We should do nothing in DECLARE sections. In SQL expressions,
* we really only need to make sure that RECFIELD datums are created
* when needed.
*/
if (plpgsql_IdentifierLookup != IDENTIFIER_LOOKUP_DECLARE)
{
/*
* Do a lookup in the current namespace stack. Must find a qualified
@ -1446,7 +1444,7 @@ plpgsql_parse_tripword(char *word1, char *word2, char *word3,
case PLPGSQL_NSTYPE_REC:
{
/*
* words 1/2 are a record name, so third word must be a
* words 1/2 are a record name, so third word could be a
* field in this record.
*/
PLpgSQL_recfield *new;
@ -1468,8 +1466,8 @@ plpgsql_parse_tripword(char *word1, char *word2, char *word3,
case PLPGSQL_NSTYPE_ROW:
{
/*
* words 1/2 are a row name, so third word must be a field
* in this row.
* words 1/2 are a row name, so third word could be a
* field in this row.
*/
PLpgSQL_row *row;
int i;
@ -1487,10 +1485,8 @@ plpgsql_parse_tripword(char *word1, char *word2, char *word3,
return true;
}
}
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("row \"%s.%s\" has no field \"%s\"",
word1, word2, word3)));
/* fall through to return CWORD */
break;
}
default:

15
src/pl/plpgsql/src/pl_scanner.c
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_scanner.c,v 1.3 2010/01/02 16:58:13 momjian Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_scanner.c,v 1.4 2010/01/10 17:15:18 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -23,8 +23,8 @@
#define PG_KEYWORD(a,b,c) {a,b,c},
/* Klugy flag to tell scanner whether to lookup identifiers */
bool plpgsql_LookupIdentifiers = true;
/* Klugy flag to tell scanner how to look up identifiers */
IdentifierLookup plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_NORMAL;
/*
* A word about keywords:
@ -33,11 +33,10 @@ bool plpgsql_LookupIdentifiers = true;
* reserved keywords are passed to the core scanner, so they will be
* recognized before (and instead of) any variable name. Unreserved
* words are checked for separately, after determining that the identifier
* isn't a known variable name. If plpgsql_LookupIdentifiers is off then
* isn't a known variable name. If plpgsql_IdentifierLookup is DECLARE then
* no variable names will be recognized, so the unreserved words always work.
* (Note in particular that this helps us avoid reserving keywords that are
* only needed in DECLARE sections, since we scan those sections with
* plpgsql_LookupIdentifiers off.)
* only needed in DECLARE sections.)
*
* In certain contexts it is desirable to prefer recognizing an unreserved
* keyword over recognizing a variable name. Those cases are handled in
@ -193,7 +192,7 @@ static void location_lineno_init(void);
* It is a wrapper around the core lexer, with the ability to recognize
* PL/pgSQL variables and return them as special T_DATUM tokens. If a
* word or compound word does not match any variable name, or if matching
* is turned off by plpgsql_LookupIdentifiers, it is returned as
* is turned off by plpgsql_IdentifierLookup, it is returned as
* T_WORD or T_CWORD respectively, or as an unreserved keyword if it
* matches one of those.
*/
@ -567,7 +566,7 @@ plpgsql_scanner_init(const char *str)
scanorig = str;
/* Other setup */
plpgsql_LookupIdentifiers = true;
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_NORMAL;
num_pushbacks = 0;

12
src/pl/plpgsql/src/plpgsql.h
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.127 2010/01/02 16:58:13 momjian Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.128 2010/01/10 17:15:18 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -795,11 +795,19 @@ typedef struct
* Global variable declarations
**********************************************************************/
typedef enum
{
IDENTIFIER_LOOKUP_NORMAL, /* normal processing of var names */
IDENTIFIER_LOOKUP_DECLARE, /* In DECLARE --- don't look up names */
IDENTIFIER_LOOKUP_EXPR /* In SQL expression --- special case */
} IdentifierLookup;
extern IdentifierLookup plpgsql_IdentifierLookup;
extern int plpgsql_variable_conflict;
extern bool plpgsql_check_syntax;
extern bool plpgsql_DumpExecTree;
extern bool plpgsql_LookupIdentifiers;
extern PLpgSQL_stmt_block *plpgsql_parse_result;