From 8cec4cf91b844e8ff3e19a444ddfa750ea4dba11 Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Wed, 14 Oct 1998 05:10:12 +0000 Subject: [PATCH] New QUERY_LIMIT set command. --- doc/src/sgml/ref/set.sgml | 38 +++++++++++++++ src/backend/commands/variable.c | 103 +++++++++++++++++++++++++++++++++++++--- src/backend/executor/execMain.c | 10 ++-- src/bin/psql/psqlHelp.h | 14 +++--- src/include/executor/executor.h | 6 ++- src/man/set.l | 8 +++- 6 files changed, 161 insertions(+), 18 deletions(-) diff --git a/doc/src/sgml/ref/set.sgml b/doc/src/sgml/ref/set.sgml index 64060984d5..87742007ef 100644 --- a/doc/src/sgml/ref/set.sgml +++ b/doc/src/sgml/ref/set.sgml @@ -415,6 +415,44 @@ Equivalent to specifying SET R_PLANS=Off. The frontend may be initialized by setting the PGRPLANS environment variable. + + +QUERY_LIMIT + + + +Sets the number of rows returned by a query. + + + + +Value + + + +Maximum number of rows to return for a query. The default is unlimited. + + +# + + + +Sets the maximum number of rows returned by a +query to #. + + +DEFAULT + + + +Sets the number of rows returned by a query to unlimited. + + + + By default, there is no limit to the number of rows + returned by a query. + + diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c index 9cf3b93008..17728b35a3 100644 --- a/src/backend/commands/variable.c +++ b/src/backend/commands/variable.c @@ -2,7 +2,7 @@ * Routines for handling of 'SET var TO', * 'SHOW var' and 'RESET var' statements. * - * $Id: variable.c,v 1.15 1998/10/08 23:50:28 tgl Exp $ + * $Id: variable.c,v 1.16 1998/10/14 05:09:58 momjian Exp $ * */ @@ -18,6 +18,10 @@ #ifdef MULTIBYTE #include "mb/pg_wchar.h" #endif +#ifdef QUERY_LIMIT +#include "executor/executor.h" +#include "executor/execdefs.h" +#endif static bool show_date(void); static bool reset_date(void); @@ -40,6 +44,11 @@ static bool parse_geqo(const char *); static bool show_ksqo(void); static bool reset_ksqo(void); static bool parse_ksqo(const char *); +#ifdef QUERY_LIMIT +static bool show_query_limit(void); +static bool reset_query_limit(void); +static bool parse_query_limit(const char *); +#endif extern Cost _cpu_page_wight_; extern Cost _cpu_index_page_wight_; @@ -48,7 +57,11 @@ extern int32 _use_geqo_rels_; extern bool _use_right_sided_plans_; extern bool _use_keyset_query_optimizer; -/*-----------------------------------------------------------------------*/ +/* + * + * Get_Token + * + */ static const char * get_token(char **tok, char **val, const char *str) { @@ -149,7 +162,11 @@ get_token(char **tok, char **val, const char *str) return str; } -/*-----------------------------------------------------------------------*/ +/* + * + * GEQO + * + */ static bool parse_geqo(const char *value) { @@ -221,6 +238,11 @@ reset_geqo(void) return TRUE; } +/* + * + * R_PLANS + * + */ static bool parse_r_plans(const char *value) { @@ -240,7 +262,6 @@ parse_r_plans(const char *value) return TRUE; } -/*-----------------------------------------------------------------------*/ static bool show_r_plans() { @@ -264,7 +285,11 @@ reset_r_plans() return TRUE; } -/*-----------------------------------------------------------------------*/ +/* + * + * COST_HEAP + * + */ static bool parse_cost_heap(const char *value) { @@ -297,7 +322,11 @@ reset_cost_heap() return TRUE; } -/*-----------------------------------------------------------------------*/ +/* + * + * COST_INDEX + * + */ static bool parse_cost_index(const char *value) { @@ -330,7 +359,11 @@ reset_cost_index() return TRUE; } -/*-----------------------------------------------------------------------*/ +/* + * + * DATE_STYLE + * + */ static bool parse_date(const char *value) { @@ -448,6 +481,11 @@ static char *defaultTZ = NULL; static char TZvalue[64]; static char tzbuf[64]; +/* + * + * TIMEZONE + * + */ /* parse_timezone() * Handle SET TIME ZONE... * Try to save existing TZ environment variable for later use in RESET TIME ZONE. @@ -545,7 +583,53 @@ reset_timezone() return TRUE; } /* reset_timezone() */ +/* + * + * Query_limit + * + */ +#ifdef QUERY_LIMIT +static bool +parse_query_limit(const char *value) +{ + int32 limit; + + if (value == NULL) { + reset_query_limit(); + return(TRUE); + } + limit = pg_atoi(value, sizeof(int32), '\0'); + if (limit <= -1) { + elog(ERROR, "Bad value for # of query limit (%s)", value); + } + ExecutorLimit(limit); + return(TRUE); +} + +static bool +show_query_limit(void) +{ + int limit; + + limit = ExecutorGetLimit(); + if (limit == ALL_TUPLES) { + elog(NOTICE, "No query limit is set"); + } else { + elog(NOTICE, "query limit is %d",limit); + } + return(TRUE); +} + +static bool +reset_query_limit(void) +{ + ExecutorLimit(ALL_TUPLES); + return(TRUE); +} +#endif + /*-----------------------------------------------------------------------*/ + struct VariableParsers { const char *name; @@ -584,6 +668,11 @@ struct VariableParsers { "ksqo", parse_ksqo, show_ksqo, reset_ksqo }, +#ifdef QUERY_LIMIT + { + "query_limit", parse_query_limit, show_query_limit, reset_query_limit + }, +#endif { NULL, NULL, NULL, NULL } diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index d55eb2a07c..a7a7cb93cc 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -26,7 +26,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.57 1998/10/01 02:03:58 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.58 1998/10/14 05:10:00 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -83,14 +83,18 @@ static int queryLimit = ALL_TUPLES; #undef ALL_TUPLES #define ALL_TUPLES queryLimit -int ExecutorLimit(int limit); - int ExecutorLimit(int limit) { return queryLimit = limit; } +int +ExecutorGetLimit() +{ + return queryLimit; +} + #endif /* ---------------------------------------------------------------- diff --git a/src/bin/psql/psqlHelp.h b/src/bin/psql/psqlHelp.h index c6d97ab4cd..7e3399332f 100644 --- a/src/bin/psql/psqlHelp.h +++ b/src/bin/psql/psqlHelp.h @@ -5,7 +5,7 @@ * * Copyright (c) 1994, Regents of the University of California * - * $Id: psqlHelp.h,v 1.53 1998/10/08 01:10:28 tgl Exp $ + * $Id: psqlHelp.h,v 1.54 1998/10/14 05:10:02 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -296,10 +296,10 @@ static struct _helpStruct QL_HELP[] = { "set run-time environment back to default", #ifdef MULTIBYTE "\ -\tRESET DateStyle|GEQO|R_PLANS|CLIENT_ENCODING"}, +\tRESET DateStyle|GEQO|R_PLANS|QUERY_LIMIT|CLIENT_ENCODING"}, #else "\ -\tRESET DateStyle|GEQO|R_PLANS"}, +\tRESET DateStyle|GEQO|R_PLANS|QUERY_LIMIT"}, #endif {"revoke", "revoke access control from a user or group", @@ -329,21 +329,23 @@ static struct _helpStruct QL_HELP[] = { \tSET DateStyle TO 'ISO'|'SQL'|'Postgres'|'European'|'US'|'NonEuropean'\n\ set GEQO TO 'ON[=#]'|'OFF'\n\ set R_PLANS TO 'ON'|'OFF'\n\ +set QUERY_LIMIT TO #\n\ set CLIENT_ENCODING TO 'EUC_JP'|'SJIS'|'EUC_CN'|'EUC_KR'|'EUC_TW'|'MULE_INTERNAL'|'LATIN1'|'LATIN2'|'LATIN3'|'LATIN4'|'LATIN5'"}, #else "\ \tSET DateStyle TO 'ISO'|'SQL'|'Postgres'|'European'|'US'|'NonEuropean'\n\ set GEQO TO 'ON[=#]'|'OFF'\n\ -set R_PLANS TO 'ON'| 'OFF'"}, +set R_PLANS TO 'ON'| 'OFF'\n\ +set QUERY_LIMIT TO #"}, #endif {"show", "show current run-time environment", #ifdef MULTIBYTE "\ -\tSHOW DateStyle|GEQO|R_PLANS|CLIENT_ENCODING"}, +\tSHOW DateStyle|GEQO|R_PLANS|QUERY_LIMIT|CLIENT_ENCODING"}, #else "\ -\tSHOW DateStyle|GEQO|R_PLANS"}, +\tSHOW DateStyle|GEQO|R_PLANS|QUERY_LIMIT"}, #endif {"unlisten", "stop listening for notification on a condition name", diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h index 3e6ae39e57..d87e57ebb2 100644 --- a/src/include/executor/executor.h +++ b/src/include/executor/executor.h @@ -6,7 +6,7 @@ * * Copyright (c) 1994, Regents of the University of California * - * $Id: executor.h,v 1.26 1998/10/08 18:30:29 momjian Exp $ + * $Id: executor.h,v 1.27 1998/10/14 05:10:05 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -86,6 +86,10 @@ extern TupleDesc ExecutorStart(QueryDesc *queryDesc, EState *estate); extern TupleTableSlot *ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, int count); extern void ExecutorEnd(QueryDesc *queryDesc, EState *estate); extern HeapTuple ExecConstraints(char *caller, Relation rel, HeapTuple tuple); +#ifdef QUERY_LIMIT +extern int ExecutorLimit(int limit); +extern int ExecutorGetLimit(void); +#endif /* * prototypes from functions in execProcnode.c diff --git a/src/man/set.l b/src/man/set.l index b1ec864023..609a88da7a 100644 --- a/src/man/set.l +++ b/src/man/set.l @@ -1,6 +1,6 @@ .\" This is -*-nroff-*- .\" XXX standard disclaimer belongs here.... -.\" $Header: /cvsroot/pgsql/src/man/Attic/set.l,v 1.10 1998/10/14 02:36:44 momjian Exp $ +.\" $Header: /cvsroot/pgsql/src/man/Attic/set.l,v 1.11 1998/10/14 05:10:12 momjian Exp $ .TH SET SQL 05/14/97 PostgreSQL PostgreSQL .SH NAME set - set run-time parameters for session @@ -76,6 +76,12 @@ by default. It's not used by GEQO anyway. off - do not use right-hand plan evaluation .fi +.PP +.IR QUERY_LIMIT +restricts the number of rows returned by a query. +The default is unlimited. + + .SH EXAMPLES .nf -- -- 2.11.0