21
PostgreSQL / Create new table with structure of another but no data
Last post by tino -Code: [Select]
CREATE TABLE new_table AS SELECT * FROM old_table WHERE 1=2;
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PHP - Upgrade all pack...
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[November 26, 2021, 08:54:45 pm] -
ESP8266 - AT Firmware
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22
PostgreSQL / timestamp round function
Last post by tino -Code: [Select]
CREATE FUNCTION ts_round( timestamptz, INT4 ) RETURNS TIMESTAMPTZ AS $$
SELECT 'epoch'::timestamptz + '1 second'::INTERVAL * ( $2 * ( extract( epoch FROM $1 )::INT4 / $2 ) );
$$ LANGUAGE SQL;
23
PostgreSQL / PostgreSQL upgrade instructions
Last post by tino -untar , then
Code: [Select]
./configure
make
Stop the old server
Code: [Select]
sudo /usr/local/pgsql/bin/pgsql.sh stop
Move the old server directory
Code: [Select]
mv /usr/local/pgsql /usr/local/pgsql-9.1.24
Now install the new server
Code: [Select]
make install
cd into the contrib/pg_upgrade directory.
Code: [Select]
make
make install
cd into the contrib/pg_upgrade_support directory.
Code: [Select]
make
make install
run the following, changing the directories to be the correct ones. old => new
Code: [Select]
su postgres
Create the new data directory
Code: [Select]
/usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data
Code: [Select]
/usr/local/pgsql/bin/pg_upgrade -b /usr/local/pgsql-9.1.24/bin/ -B /usr/local/pgsql/bin/ -d /usr/local/pgsql-9.1.24/data -D /usr/local/pgsql/data
Copy the pgsql.sh file to the new bin location.
Code: [Select]
cp /usr/local/pgsql-9.1.24/bin/pgsql.sh /usr/local/pgsql/bin/
Code: [Select]
mkdir /usr/local/pgsql/log
Code: [Select]
chown postgres:postgres /usr/local/pgsql/log
edit the pg_hba.conf file and add the following to the end
Code: [Select]
# Allow any user from host 192.168.1.x to connect to
# any database if the user's password is correctly supplied.
# TYPE DATABASE USER ADDRESS METHOD
host all all 192.168.1.0/24 md5
start the server again.
24
C Code / WatchDog Timer
Last post by tino -Code: [Select]
#include <avr/sleep.h>
#include <avr/power.h>
#include <avr/wdt.h>
/*
Watchdog Timer Prescale Select
WDP3 WDP2 WDP1 WDP0 Number of WDT Typical Time-out at Oscillator Cycles VCC = 5.0V
0 0 0 0 2K (2048) cycles 16 ms
0 0 0 1 4K (4096) cycles 32 ms
0 0 1 0 8K (8192) cycles 64 ms
0 0 1 1 16K (16384) cycles 0.125 s
0 1 0 0 32K (32768) cycles 0.25 s
0 1 0 1 64K (65536) cycles 0.5 s
0 1 1 0 128K (131072) cycles 1.0 s
0 1 1 1 256K (262144) cycles 2.0 s
1 0 0 0 512K (524288) cycles 4.0 s
1 0 0 1 1024K (1048576) cycles 8.0 s
*/
unsigned int i = 0;
void setup(void) {
Serial.begin(57600);
MCUSR &= ~(1 << WDRF); // reset status flag
WDTCSR |= (1 << WDCE) | (1 << WDE); // enable configuration changes
WDTCSR = (1<< WDP0) | ( 1 << WDP3); // set the prescalar = 9
WDTCSR |= (1 << WDIE); // enable interrupt mode
}
void loop(void) {
set_sleep_mode(SLEEP_MODE_PWR_DOWN); // select the watchdog timer mode
sleep_enable(); // enable the sleep mode ready for use
sleep_mode(); // trigger the sleep
Serial.print("Woken ");
Serial.println(i++);
Serial.flush();
sleep_disable(); // prevent further sleeps
}
ISR(WDT_vect) {
}