From db61437b274a5d9134467346bf7bf996877cc5f6 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 23 Mar 2006 04:22:45 +0000 Subject: [PATCH] Fix plpgsql to pass only one copy of any given plpgsql variable into a SQL command or expression, rather than one copy for each textual occurrence as it did before. This might result in some small performance improvement, but the compelling reason to do it is that not doing so can result in unexpected grouping failures because the main SQL parser won't see different parameter numbers as equivalent. Add a regression test for the failure case. Per report from Robert Davidson. --- src/pl/plpgsql/src/gram.y | 92 +++++++++++++++++---------- src/test/regress/expected/plpgsql.out | 18 ++++++ src/test/regress/sql/plpgsql.sql | 15 +++++ 3 files changed, 92 insertions(+), 33 deletions(-) diff --git a/src/pl/plpgsql/src/gram.y b/src/pl/plpgsql/src/gram.y index 8e7097c9619..dd4ea9ccdeb 100644 --- a/src/pl/plpgsql/src/gram.y +++ b/src/pl/plpgsql/src/gram.y @@ -4,7 +4,7 @@ * procedural language * * IDENTIFICATION - * $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.82 2005/10/13 15:34:19 tgl Exp $ + * $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.82.2.1 2006/03/23 04:22:44 tgl Exp $ * * This software is copyrighted by Jan Wieck - Hamburg. * @@ -1666,6 +1666,44 @@ lno : %% +#define MAX_EXPR_PARAMS 1024 + +/* + * determine the expression parameter position to use for a plpgsql datum + * + * It is important that any given plpgsql datum map to just one parameter. + * We used to be sloppy and assign a separate parameter for each occurrence + * of a datum reference, but that fails for situations such as "select DATUM + * from ... group by DATUM". + * + * The params[] array must be of size MAX_EXPR_PARAMS. + */ +static int +assign_expr_param(int dno, int *params, int *nparams) +{ + int i; + + /* already have an instance of this dno? */ + for (i = 0; i < *nparams; i++) + { + if (params[i] == dno) + return i+1; + } + /* check for array overflow */ + if (*nparams >= MAX_EXPR_PARAMS) + { + plpgsql_error_lineno = plpgsql_scanner_lineno(); + ereport(ERROR, + (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED), + errmsg("too many variables specified in SQL statement"))); + } + /* add new parameter dno to array */ + params[*nparams] = dno; + (*nparams)++; + return *nparams; +} + + PLpgSQL_expr * plpgsql_read_expression(int until, const char *expected) { @@ -1704,7 +1742,7 @@ read_sql_construct(int until, PLpgSQL_dstring ds; int parenlevel = 0; int nparams = 0; - int params[1024]; + int params[MAX_EXPR_PARAMS]; char buf[32]; PLpgSQL_expr *expr; @@ -1756,32 +1794,26 @@ read_sql_construct(int until, if (plpgsql_SpaceScanned) plpgsql_dstring_append(&ds, " "); - /* Check for array overflow */ - if (nparams >= 1024) - { - plpgsql_error_lineno = lno; - ereport(ERROR, - (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED), - errmsg("too many variables specified in SQL statement"))); - } - switch (tok) { case T_SCALAR: - params[nparams] = yylval.scalar->dno; - snprintf(buf, sizeof(buf), " $%d ", ++nparams); + snprintf(buf, sizeof(buf), " $%d ", + assign_expr_param(yylval.scalar->dno, + params, &nparams)); plpgsql_dstring_append(&ds, buf); break; case T_ROW: - params[nparams] = yylval.row->rowno; - snprintf(buf, sizeof(buf), " $%d ", ++nparams); + snprintf(buf, sizeof(buf), " $%d ", + assign_expr_param(yylval.row->rowno, + params, &nparams)); plpgsql_dstring_append(&ds, buf); break; case T_RECORD: - params[nparams] = yylval.rec->recno; - snprintf(buf, sizeof(buf), " $%d ", ++nparams); + snprintf(buf, sizeof(buf), " $%d ", + assign_expr_param(yylval.rec->recno, + params, &nparams)); plpgsql_dstring_append(&ds, buf); break; @@ -1879,7 +1911,7 @@ make_select_stmt(void) { PLpgSQL_dstring ds; int nparams = 0; - int params[1024]; + int params[MAX_EXPR_PARAMS]; char buf[32]; PLpgSQL_expr *expr; PLpgSQL_row *row = NULL; @@ -1942,32 +1974,26 @@ make_select_stmt(void) if (plpgsql_SpaceScanned) plpgsql_dstring_append(&ds, " "); - /* Check for array overflow */ - if (nparams >= 1024) - { - plpgsql_error_lineno = plpgsql_scanner_lineno(); - ereport(ERROR, - (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED), - errmsg("too many parameters specified in SQL statement"))); - } - switch (tok) { case T_SCALAR: - params[nparams] = yylval.scalar->dno; - snprintf(buf, sizeof(buf), " $%d ", ++nparams); + snprintf(buf, sizeof(buf), " $%d ", + assign_expr_param(yylval.scalar->dno, + params, &nparams)); plpgsql_dstring_append(&ds, buf); break; case T_ROW: - params[nparams] = yylval.row->rowno; - snprintf(buf, sizeof(buf), " $%d ", ++nparams); + snprintf(buf, sizeof(buf), " $%d ", + assign_expr_param(yylval.row->rowno, + params, &nparams)); plpgsql_dstring_append(&ds, buf); break; case T_RECORD: - params[nparams] = yylval.rec->recno; - snprintf(buf, sizeof(buf), " $%d ", ++nparams); + snprintf(buf, sizeof(buf), " $%d ", + assign_expr_param(yylval.rec->recno, + params, &nparams)); plpgsql_dstring_append(&ds, buf); break; diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out index aef73e1eee7..961fe9f46ee 100644 --- a/src/test/regress/expected/plpgsql.out +++ b/src/test/regress/expected/plpgsql.out @@ -2721,3 +2721,21 @@ end; $$ language plpgsql; ERROR: end label "outer_label" specified for unlabelled block CONTEXT: compile of PL/pgSQL function "end_label4" near line 5 +-- regression test: verify that multiple uses of same plpgsql datum within +-- a SQL command all get mapped to the same $n parameter. The return value +-- of the SELECT is not important, we only care that it doesn't fail with +-- a complaint about an ungrouped column reference. +create function multi_datum_use(p1 int) returns bool as $$ +declare + x int; + y int; +begin + select into x,y unique1/p1, unique1/$1 from tenk1 group by unique1/p1; + return x = y; +end$$ language plpgsql; +select multi_datum_use(42); + multi_datum_use +----------------- + t +(1 row) + diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql index fdb2f46ff89..6bffb3e13b6 100644 --- a/src/test/regress/sql/plpgsql.sql +++ b/src/test/regress/sql/plpgsql.sql @@ -2280,3 +2280,18 @@ begin end loop outer_label; end; $$ language plpgsql; + +-- regression test: verify that multiple uses of same plpgsql datum within +-- a SQL command all get mapped to the same $n parameter. The return value +-- of the SELECT is not important, we only care that it doesn't fail with +-- a complaint about an ungrouped column reference. +create function multi_datum_use(p1 int) returns bool as $$ +declare + x int; + y int; +begin + select into x,y unique1/p1, unique1/$1 from tenk1 group by unique1/p1; + return x = y; +end$$ language plpgsql; + +select multi_datum_use(42);