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Create a standard function pg_sleep() to sleep for a specified amount of time.
Replace the former ad-hoc implementation used in the regression tests. Joachim Wieland
This commit is contained in:
Tom Lane
parent
fb627b76cc
commit
782eefc580
@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.301 2005/12/28 01:29:58 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.302 2006/01/11 20:12:38 tgl Exp $
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PostgreSQL documentation
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-->
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@ -6170,6 +6170,56 @@ SELECT TIMESTAMP 'now'; -- incorrect for use with DEFAULT
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</para>
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</tip>
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</sect2>
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<sect2 id="functions-datetime-delay">
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<title>Delaying Execution</title>
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<indexterm>
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<primary>pg_sleep</primary>
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</indexterm>
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<indexterm>
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<primary>sleep</primary>
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</indexterm>
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<indexterm>
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<primary>delay</primary>
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</indexterm>
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<para>
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The following function is available to delay execution of the server
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process:
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<synopsis>
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pg_sleep(<replaceable>seconds</replaceable>)
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</synopsis>
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<function>pg_sleep</function> makes the current session's process
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sleep until <replaceable>seconds</replaceable> seconds have
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elapsed. <replaceable>seconds</replaceable> is a value of type
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<type>double precision</>, so fractional-second delays can be specified.
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For example:
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<programlisting>
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SELECT pg_sleep(1.5);
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</programlisting>
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</para>
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<note>
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<para>
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The effective resolution of the sleep interval is platform-specific;
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0.01 seconds is a common value. The sleep delay will be at least as long
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as specified. It may be longer depending on factors such as server load.
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</para>
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</note>
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<warning>
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<para>
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Make sure that your session does not hold more locks than necessary
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when calling <function>pg_sleep</function>. Otherwise other sessions
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might have to wait for your sleeping process, slowing down the entire
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system.
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</para>
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</warning>
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</sect2>
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</sect1>
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/misc.c,v 1.49 2005/10/15 02:49:29 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/misc.c,v 1.50 2006/01/11 20:12:39 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -17,6 +17,7 @@
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#include <sys/file.h>
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#include <signal.h>
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#include <dirent.h>
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#include <math.h>
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#include "catalog/pg_tablespace.h"
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#include "catalog/pg_type.h"
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@ -259,3 +260,51 @@ pg_tablespace_databases(PG_FUNCTION_ARGS)
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FreeDir(fctx->dirdesc);
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SRF_RETURN_DONE(funcctx);
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}
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/*
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* pg_sleep - delay for N seconds
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*/
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Datum
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pg_sleep(PG_FUNCTION_ARGS)
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{
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float8 secs = PG_GETARG_FLOAT8(0);
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float8 endtime;
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/*
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* We break the requested sleep into segments of no more than 1 second,
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* to put an upper bound on how long it will take us to respond to a
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* cancel or die interrupt. (Note that pg_usleep is interruptible by
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* signals on some platforms but not others.) Also, this method avoids
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* exposing pg_usleep's upper bound on allowed delays.
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*
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* By computing the intended stop time initially, we avoid accumulation
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* of extra delay across multiple sleeps. This also ensures we won't
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* delay less than the specified time if pg_usleep is interrupted
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* by other signals such as SIGHUP.
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*/
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#ifdef HAVE_INT64_TIMESTAMP
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#define GetNowFloat() ((float8) GetCurrentTimestamp() / 1000000.0)
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#else
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#define GetNowFloat() GetCurrentTimestamp()
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#endif
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endtime = GetNowFloat() + secs;
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for (;;)
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{
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float8 delay;
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CHECK_FOR_INTERRUPTS();
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delay = endtime - GetNowFloat();
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if (delay >= 1.0)
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pg_usleep(1000000L);
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else if (delay > 0.0)
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pg_usleep((long) ceil(delay * 1000000.0));
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else
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break;
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}
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PG_RETURN_VOID();
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}
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@ -37,7 +37,7 @@
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.309 2006/01/08 07:00:25 neilc Exp $
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* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.310 2006/01/11 20:12:39 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -53,6 +53,6 @@
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*/
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/* yyyymmddN */
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#define CATALOG_VERSION_NO 200601081
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#define CATALOG_VERSION_NO 200601111
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#endif
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.390 2006/01/08 07:00:25 neilc Exp $
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* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.391 2006/01/11 20:12:39 tgl Exp $
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*
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* NOTES
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* The script catalog/genbki.sh reads this file and generates .bki
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@ -3025,6 +3025,8 @@ DATA(insert OID = 2624 ( pg_read_file PGNSP PGUID 12 f f t f v 3 25 "25 20 20"
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DESCR("Read text from a file");
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DATA(insert OID = 2625 ( pg_ls_dir PGNSP PGUID 12 f f t t v 1 25 "25" _null_ _null_ _null_ pg_ls_dir - _null_ ));
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DESCR("List all files in a directory");
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DATA(insert OID = 2626 ( pg_sleep PGNSP PGUID 12 f f t f v 1 2278 "701" _null_ _null_ _null_ pg_sleep - _null_ ));
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DESCR("Sleep for the specified time in seconds");
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/* Aggregates (moved here from pg_aggregate for 7.3) */
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.269 2006/01/08 07:00:26 neilc Exp $
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* $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.270 2006/01/11 20:12:42 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -387,6 +387,7 @@ extern Datum pg_cancel_backend(PG_FUNCTION_ARGS);
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extern Datum pg_reload_conf(PG_FUNCTION_ARGS);
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extern Datum pg_tablespace_databases(PG_FUNCTION_ARGS);
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extern Datum pg_rotate_logfile(PG_FUNCTION_ARGS);
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extern Datum pg_sleep(PG_FUNCTION_ARGS);
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/* not_in.c */
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extern Datum int4notin(PG_FUNCTION_ARGS);
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@ -36,8 +36,8 @@ SELECT count(*) FROM tenk2 WHERE unique1 = 1;
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(1 row)
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-- let stats collector catch up
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SELECT do_sleep(2);
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do_sleep
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SELECT pg_sleep(2.0);
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pg_sleep
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----------
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(1 row)
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@ -52,11 +52,6 @@ CREATE FUNCTION set_ttdummy (int4)
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AS '@abs_builddir@/regress@DLSUFFIX@'
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LANGUAGE 'C' STRICT;
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CREATE FUNCTION do_sleep (int4)
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RETURNS void
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AS '@abs_builddir@/regress@DLSUFFIX@'
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LANGUAGE 'C' STRICT;
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-- Things that shouldn't work:
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CREATE FUNCTION test1 (int) RETURNS int LANGUAGE sql
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@ -47,10 +47,6 @@ CREATE FUNCTION set_ttdummy (int4)
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RETURNS int4
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AS '@abs_builddir@/regress@DLSUFFIX@'
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LANGUAGE 'C' STRICT;
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CREATE FUNCTION do_sleep (int4)
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RETURNS void
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AS '@abs_builddir@/regress@DLSUFFIX@'
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LANGUAGE 'C' STRICT;
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-- Things that shouldn't work:
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CREATE FUNCTION test1 (int) RETURNS int LANGUAGE sql
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AS 'SELECT ''not an integer'';';
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@ -1,5 +1,5 @@
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/*
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* $PostgreSQL: pgsql/src/test/regress/regress.c,v 1.64 2005/10/15 02:49:51 momjian Exp $
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* $PostgreSQL: pgsql/src/test/regress/regress.c,v 1.65 2006/01/11 20:12:43 tgl Exp $
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*/
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#include "postgres.h"
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@ -26,7 +26,6 @@ extern char *reverse_name(char *string);
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extern int oldstyle_length(int n, text *t);
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extern Datum int44in(PG_FUNCTION_ARGS);
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extern Datum int44out(PG_FUNCTION_ARGS);
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extern Datum do_sleep(PG_FUNCTION_ARGS);
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/*
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@ -735,18 +734,3 @@ int44out(PG_FUNCTION_ARGS)
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*--walk = '\0';
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PG_RETURN_CSTRING(result);
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}
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/*
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* do_sleep - delay for N seconds
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*/
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PG_FUNCTION_INFO_V1(do_sleep);
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Datum
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do_sleep(PG_FUNCTION_ARGS)
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{
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int32 secs = PG_GETARG_INT32(0);
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pg_usleep(secs * 1000000L);
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PG_RETURN_VOID();
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}
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@ -26,7 +26,7 @@ SELECT count(*) FROM tenk2;
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SELECT count(*) FROM tenk2 WHERE unique1 = 1;
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-- let stats collector catch up
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SELECT do_sleep(2);
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SELECT pg_sleep(2.0);
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-- check effects
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SELECT st.seq_scan >= pr.seq_scan + 1,
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