From 77a162f968c36e18890d0f845a8ebbb501769c10 Mon Sep 17 00:00:00 2001 From: Daniel Gustafsson Date: Fri, 14 Feb 2025 15:11:23 +0100 Subject: [PATCH v7] psql: Make default \watch interval configurable The default interval for \watch to wait between executing queries, when executed without a specified interval, was hardcoded to two seconds. This adds the new variable WATCH_INTERVAL which is used to set the default interval, making it configurable for the user. Author: Daniel Gustafsson Reviewed-by: Heikki Linnakangas Reviewed-by: Michael Paquier Reviewed-by: Kirill Reshke Reviewed-by: Masahiro Ikeda Reviewed-by: Laurenz Albe Reviewed-by: Greg Sabino Mullane Reviewed-by: Ashutosh Bapat Discussion: https://postgr.es/m/B2FD26B4-8F64-4552-A603-5CC3DF1C7103@yesql.se --- doc/src/sgml/ref/psql-ref.sgml | 16 +++++++- src/bin/psql/command.c | 6 ++- src/bin/psql/help.c | 2 + src/bin/psql/settings.h | 7 ++++ src/bin/psql/startup.c | 18 +++++++++ src/bin/psql/t/001_basic.pl | 24 ++++++++++++ src/bin/psql/variables.c | 70 ++++++++++++++++++++++++++++++++++ src/bin/psql/variables.h | 3 ++ 8 files changed, 142 insertions(+), 4 deletions(-) diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml index f083dba49a9..5ead1c784a0 100644 --- a/doc/src/sgml/ref/psql-ref.sgml +++ b/doc/src/sgml/ref/psql-ref.sgml @@ -3851,8 +3851,9 @@ SELECT 1 \bind \sendpipeline Repeatedly execute the current query buffer (as \g does) until interrupted, or the query fails, or the execution count limit (if given) is reached, or the query no longer returns the minimum number - of rows. Wait the specified number of seconds (default 2) between executions. - For backwards compatibility, + of rows. Wait the specified number of seconds (defaults to 2 if omitted, which can be + changed with the variable ) + between executions. For backwards compatibility, seconds can be specified with or without an interval= prefix. Each query result is @@ -4746,6 +4747,17 @@ bar + + WATCH_INTERVAL + + + This variable sets the default interval which \watch + waits between executing the query. Specifying an interval in the + command overrides this variable. + + + + diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c index bbe337780ff..015ece77aec 100644 --- a/src/bin/psql/command.c +++ b/src/bin/psql/command.c @@ -3278,7 +3278,7 @@ exec_command_watch(PsqlScanState scan_state, bool active_branch, bool have_sleep = false; bool have_iter = false; bool have_min_rows = false; - double sleep = 2; + double sleep = pset.watch_interval; int iter = 0; int min_rows = 0; @@ -3292,7 +3292,9 @@ exec_command_watch(PsqlScanState scan_state, bool active_branch, /* * Parse arguments. We allow either an unlabeled interval or * "name=value", where name is from the set ('i', 'interval', 'c', - * 'count', 'm', 'min_rows'). + * 'count', 'm', 'min_rows'). The parsing of interval value should + * be kept in sync with ParseVariableDouble which is used for setting + * the default interval value. */ while (success) { diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c index e47cad24de9..30e3792d263 100644 --- a/src/bin/psql/help.c +++ b/src/bin/psql/help.c @@ -460,6 +460,8 @@ helpVariables(unsigned short int pager) " VERSION_NAME\n" " VERSION_NUM\n" " psql's version (in verbose string, short string, or numeric format)\n"); + HELP0(" WATCH_INTERVAL\n" + " number of seconds \\watch waits between executing the query buffer\n"); HELP0("\nDisplay settings:\n"); HELP0("Usage:\n"); diff --git a/src/bin/psql/settings.h b/src/bin/psql/settings.h index 71f553c22ad..fd82303f776 100644 --- a/src/bin/psql/settings.h +++ b/src/bin/psql/settings.h @@ -27,6 +27,12 @@ #define DEFAULT_PROMPT2 "%/%R%x%# " #define DEFAULT_PROMPT3 ">> " +#define DEFAULT_WATCH_INTERVAL "2" +/* + * Limit the max default setting to a value which should be safe for the + * itimer call, yet large enough to cover all realistic usecases. + */ +#define DEFAULT_WATCH_INTERVAL_MAX (1000*1000) /* * Note: these enums should generally be chosen so that zero corresponds * to the default behavior. @@ -166,6 +172,7 @@ typedef struct _psqlSettings int fetch_count; int histsize; int ignoreeof; + double watch_interval; PSQL_ECHO echo; PSQL_ECHO_HIDDEN echo_hidden; PSQL_ERROR_ROLLBACK on_error_rollback; diff --git a/src/bin/psql/startup.c b/src/bin/psql/startup.c index 5018eedf1e5..249b6aa5169 100644 --- a/src/bin/psql/startup.c +++ b/src/bin/psql/startup.c @@ -944,6 +944,21 @@ histsize_hook(const char *newval) return ParseVariableNum(newval, "HISTSIZE", &pset.histsize); } +static char * +watch_interval_substitute_hook(char *newval) +{ + if (newval == NULL) + newval = pg_strdup(DEFAULT_WATCH_INTERVAL); + return newval; +} + +static bool +watch_interval_hook(const char *newval) +{ + return ParseVariableDouble(newval, "WATCH_INTERVAL", &pset.watch_interval, + 0, DEFAULT_WATCH_INTERVAL_MAX); +} + static char * ignoreeof_substitute_hook(char *newval) { @@ -1270,4 +1285,7 @@ EstablishVariableSpace(void) SetVariableHooks(pset.vars, "HIDE_TABLEAM", bool_substitute_hook, hide_tableam_hook); + SetVariableHooks(pset.vars, "WATCH_INTERVAL", + watch_interval_substitute_hook, + watch_interval_hook); } diff --git a/src/bin/psql/t/001_basic.pl b/src/bin/psql/t/001_basic.pl index dca34ac975a..7192d96049d 100644 --- a/src/bin/psql/t/001_basic.pl +++ b/src/bin/psql/t/001_basic.pl @@ -375,6 +375,12 @@ psql_like( $node, sprintf('SELECT 1 \watch c=3 i=%g', 0.0001), qr/1\n1\n1/, '\watch with 3 iterations, interval of 0.0001'); +# Test zero interval +psql_like( + $node, '\set WATCH_INTERVAL 0 +SELECT 1 \watch c=3', + qr/1\n1\n1/, '\watch with 3 iterations, interval of 0'); + # Check \watch minimum row count psql_fails_like( $node, @@ -426,6 +432,24 @@ psql_fails_like( qr/iteration count is specified more than once/, '\watch, iteration count is specified more than once'); +# Check WATCH_INTERVAL +psql_like( + $node, + '\echo :WATCH_INTERVAL +\set WATCH_INTERVAL 0.001 +\echo :WATCH_INTERVAL +\unset WATCH_INTERVAL +\echo :WATCH_INTERVAL', + qr/^2$ +^0.001$ +^2$/m, + 'WATCH_INTERVAL variable is set and updated'); +psql_fails_like( + $node, + '\set WATCH_INTERVAL 1e500', + qr/is out of range/, + 'WATCH_INTERVAL variable is out of range'); + # Test \g output piped into a program. # The program is perl -pe '' to simply copy the input to the output. my $g_file = "$tempdir/g_file_1.out"; diff --git a/src/bin/psql/variables.c b/src/bin/psql/variables.c index 59956028918..5150eb0532b 100644 --- a/src/bin/psql/variables.c +++ b/src/bin/psql/variables.c @@ -7,6 +7,8 @@ */ #include "postgres_fe.h" +#include + #include "common.h" #include "common/logging.h" #include "variables.h" @@ -179,6 +181,74 @@ ParseVariableNum(const char *value, const char *name, int *result) } } +/* + * Try to interpret "value" as a double value, and if successful store it in + * *result. If unsuccessful, *result isn't clobbered. "name" is the variable + * which is being assigned, the value of which is only used to produce a good + * error message. Pass NULL as the name to suppress the error message. The + * value must be within the range [min,max] in order to be considered valid. + * + * Returns true, with *result containing the interpreted value, if "value" is + * syntactically valid, else false (with *result unchanged). + */ +bool +ParseVariableDouble(const char *value, const char *name, double *result, double min, double max) +{ + char *end; + double dblval; + + /* + * Empty-string input has historically been treated differently by strtod + * on various platforms, so handle that by specifically checking for it. + */ + if ((value == NULL) || (*value == '\0')) + { + if (name) + pg_log_error("invalid input syntax for \"%s\"", name); + return false; + } + + errno = 0; + dblval = strtod(value, &end); + if (errno == 0 && *end == '\0' && end != value) + { + if (dblval < min) + { + if (name) + pg_log_error("invalid value \"%s\" for \"%s\": must be greater than %.2f", + value, name, min); + return false; + } + else if (dblval > max) + { + if (name) + pg_log_error("invalid value \"%s\" for \"%s\": must be less than %.2f", + value, name, max); + } + *result = dblval; + return true; + } + + /* + * Cater for platforms which treat values which aren't zero, but that are + * too close to zero to have full precision, by checking for zero or real + * out-of-range values. + */ + else if ((errno = ERANGE) && + (dblval == 0.0 || dblval >= HUGE_VAL || dblval <= -HUGE_VAL)) + { + if (name) + pg_log_error("\"%s\" is out of range for \"%s\"", value, name); + return false; + } + else + { + if (name) + pg_log_error("invalid value \"%s\" for \"%s\"", value, name); + return false; + } +} + /* * Print values of all variables. */ diff --git a/src/bin/psql/variables.h b/src/bin/psql/variables.h index a95bc29f407..df23ccb987d 100644 --- a/src/bin/psql/variables.h +++ b/src/bin/psql/variables.h @@ -81,6 +81,9 @@ bool ParseVariableBool(const char *value, const char *name, bool ParseVariableNum(const char *value, const char *name, int *result); +bool ParseVariableDouble(const char *value, const char *name, + double *result, double min, double max); + void PrintVariables(VariableSpace space); bool SetVariable(VariableSpace space, const char *name, const char *value); -- 2.39.3 (Apple Git-146)