Postgresql on FromDual GmbH

Comparing Optimizer Results

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 18 Nov 2022 10:59:18 +0000

A while ago I read a paper about Optimizer Benchmarks: How Good Are Query Optimizers, Really? by Viktor Leis from Fakultät für Informatik of the Technische Universität München.

Databases are standardized but in detail they behave different

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 10 Feb 2021 11:47:20 +0000

For a fancy application we want to query a chunk of rows from a table and therefore we need the minimum and the maximum of the Primary Key of these rows.
Because InnoDB is an Index Organized Table or Index Clustered Table we know that this access will use the Primary Key. But to be sure and to be compliant with the standard (and compatible) we use and ORDER BY on the Primary Key.

Who else is using my memory - File System Cache analysis

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 19 Jul 2019 15:52:32 +0200

Do not underestimate performance impacts of swapping on NUMA database systems

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 21 Jun 2019 09:26:59 +0200

If your MariaDB or MySQL database system is swapping it can have a significant impact on your database query performance! Further it can also slow down your database shutdown and thus influence the whole reboot of your machine. This is especially painful if you have only short maintenance windows or if you do not want to spend the whole night with operation tasks.

MariaDB and MySQL swap analysis

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 14 Aug 2018 17:51:32 +0000

# free
 total used free shared buff/cache available
Mem: 16106332 3914228 367072 296508 11825032 11441608
Swap: 31250428 182924 31067504

# cat /proc/meminfo | grep ^Swap
SwapCached: 10056 kB
SwapTotal: 31250428 kB
SwapFree: 31067504 kB

# for file in /proc/*/status ; do
 awk '/VmSwap|Name/{
 if ( $2 != "0" )
 printf $2 " " $3
 }END{ print ""}' $file
done | grep kB | sort -k 2 -n -r

mysqld 29988 kB
plasmashell 19096 kB
kwin_x11 13444 kB
Xorg 13328 kB
krunner 11200 kB
knotes 5768 kB
kded5 5016 kB
korgac 4760 kB
kglobalaccel5 3288 kB
kwalletd 3148 kB
kaccess 3148 kB
polkit-kde-auth 2704 kB
xembedsniproxy 2660 kB
akonadi_control 2652 kB
kwalletd5 2616 kB
python 2572 kB
kactivitymanage 2508 kB
klauncher 2352 kB
kdeinit5 2324 kB
ksmserver 2256 kB
python 1480 kB
pulseaudio 1312 kB
sddm-helper 1172 kB
baloo_file 1172 kB
kscreen_backend 1132 kB
mission-control 1104 kB
python 992 kB
TeamDrive.bin 772 kB
sddm 772 kB
akonadiserver 616 kB
systemd 504 kB
at-spi2-registr 488 kB
systemd 472 kB
kwrapper5 468 kB
dbus-launch 400 kB
dbus-launch 396 kB
(sd-pam) 364 kB
dbus-daemon 328 kB
(sd-pam) 300 kB
at-spi-bus-laun 264 kB
obexd 260 kB
ssh-agent 252 kB
dbus-daemon 216 kB
gnome-keyring-d 212 kB
dbus-daemon 200 kB
gpg-agent 104 kB
startkde 100 kB
skypeforlinux 64 kB
start_kdeinit 60 kB
apache2 32 kB
apache2 32 kB
apache2 32 kB
apache2 32 kB
apache2 32 kB
apache2 32 kB

# sudo smem --totals --sort=swap
 PID User Command Swap USS PSS RSS
...
 1500 root /usr/sbin/apache2 -k start 32 5616 9534 23740 
10469 www-data /usr/sbin/apache2 -k start 32 136 1421 9848 
10470 www-data /usr/sbin/apache2 -k start 32 132 1418 9848 
10471 www-data /usr/sbin/apache2 -k start 32 132 1418 9848 
10472 www-data /usr/sbin/apache2 -k start 32 132 1418 9848 
10473 www-data /usr/sbin/apache2 -k start 32 132 1418 9848 
 2111 oli /usr/lib/x86_64-linux-gnu/l 60 40 43 548 
 2291 oli /usr/share/skypeforlinux/sk 60 73920 80765 106312 
 1957 oli /bin/sh /usr/bin/startkde 100 8 54 1576 
 2050 oli /usr/bin/gpg-agent --daemon 104 256 278 1924 
 2056 oli /usr/bin/dbus-daemon --fork 200 1740 1820 4480 
 1951 oli /usr/bin/gnome-keyring-daem 212 704 887 5768 
 2132 oli /usr/bin/dbus-daemon --conf 216 712 806 3924 
 2052 oli /usr/bin/ssh-agent /usr/bin 252 204 209 908 
 2315 oli /usr/lib/bluetooth/obexd 260 1084 1345 7936 
 2127 oli /usr/lib/at-spi2-core/at-sp 264 536 625 5700 
 1228 sddm (sd-pam) 300 1412 1728 3036 
 1476 sddm /usr/bin/dbus-daemon --fork 328 56 143 2748 
 1946 oli (sd-pam) 364 1216 1615 3132 
 1475 sddm dbus-launch --autolaunch 61 396 8 28 2252 
 2055 oli /usr/bin/dbus-launch --exit 400 8 24 2160 
 1223 sddm /lib/systemd/systemd --user 444 432 995 4376 
 1937 oli /lib/systemd/systemd --user 448 404 971 4400 
 2144 oli kwrapper5 /usr/bin/ksmserve 468 4 102 6356 
 2134 oli /usr/lib/at-spi2-core/at-sp 488 268 343 5776 
 2223 oli akonadiserver 616 11196 11401 21988 
 1129 root /usr/bin/sddm 724 716 963 11848 
 2277 oli ./TeamDrive.bin autostart 772 352656 353309 365768 
 2298 oli python /usr/bin/hp-systray 992 4904 7157 15340 
 2162 oli /usr/lib/telepathy/mission- 1104 1196 1540 8640 
 2166 oli /usr/lib/x86_64-linux-gnu/l 1132 696 973 15148 
 1934 root /usr/lib/x86_64-linux-gnu/s 1172 352 802 10996 
 2177 oli /usr/bin/baloo_file 1172 74356 74784 90584 
 2208 oli /usr/bin/pulseaudio --start 1312 4520 4897 10672 
 2299 oli python /usr/bin/hp-systray 1480 3152 5448 11184 
 2146 oli /usr/bin/ksmserver 2256 5024 6013 34104 
 2115 oli kdeinit5: Running... 2324 264 748 15492 
 2116 oli klauncher [kdeinit5] --fd=9 2352 1256 1997 21712 
 2154 oli /usr/bin/kactivitymanagerd 2472 4588 5337 29772 
 2284 oli python /usr/bin/hp-systray 2572 15216 18372 37452 
 1956 oli /usr/bin/kwalletd5 --pam-lo 2616 5272 6454 37400 
 2219 oli /usr/bin/akonadi_control 2652 2048 2450 23964 
 2195 oli /usr/bin/xembedsniproxy 2660 968 1405 23600 
 2190 oli /usr/lib/x86_64-linux-gnu/l 2704 1172 1703 26716 
 1954 oli /usr/bin/kwalletd --pam-log 3144 1180 1601 12784 
 2124 oli /usr/bin/kaccess 3148 708 1110 21276 
 2151 oli /usr/bin/kglobalaccel5 3288 1316 1799 25164 
 2203 oli /usr/bin/korgac -session 10 4760 1384 2093 28576 
 2118 oli kded5 [kdeinit5] 5016 77440 78828 107932 
 2217 oli /usr/bin/knotes -session 10 5768 7048 8467 41744 
 2179 oli /usr/bin/krunner 11200 16276 19166 55272 
 1148 root /usr/lib/xorg/Xorg -noliste 13316 31464 45953 68016 
 2167 oli kwin_x11 -session 106368656 13444 35972 39318 76556 
 2186 oli /usr/bin/plasmashell --shut 19096 90608 94701 135284 
 2224 oli /usr/sbin/mysqld --defaults 29988 148588 148624 151832 
-------------------------------------------------------------------------------
 170 14 150808 4085792 4318525 6436312 

# sudo smem --totals --sort=swap | grep -e mysql -e Command
 PID User Command Swap USS PSS RSS 
 6903 mysql /home/mysql/product/mariadb 0 191000 191071 194964 
16937 mysql /home/mysql/product/mysql-8 0 358812 358865 362364 
17480 mysql /home/mysql/product/mysql-5 0 271420 273310 278692 
28484 root grep -e mysql -e Command 0 352 395 2404 
29071 mysql /bin/sh bin/mysqld_safe --d 0 152 227 1724 
29326 mysql /home/mysql/product/mysql-5 0 506848 508747 514268 
 2224 oli /usr/sbin/mysqld --defaults 29988 148588 148624 151832

Migration from other databases to MySQL or MariaDB

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 03 Jul 2015 08:32:31 +0000

Database migration tools

A generic database migration tool to MySQL and MariaDB is the MySQL Workbench.

Presentations

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 26 Feb 2010 21:29:43 +0100

The following presentations are available:

Date	Title	Location	Lang
September 2026	PostgreSQL Daten retten (PDF, 952 kib)	LinuxDay 2026, 26 September 2026, HTL Dornbirn, Austria	Ger
November 2025	MySQL Honeypot (PDF, 324 kib)	DOAG 2025 Konferenz + Ausstellung, 18 - 20 November 2025, Nürnberg, Germany	Ger
November 2024	MySQL Performance Tuning (PDF, 791 kib), Was ist neu in MySQL 8.4? (PDF, 407 kib)	DOAG 2024 Konferenz + Ausstellung, 19 - 21 November 2024, Nürnberg, Germany	Ger
August 2024	Was ist neu in MariaDB 11.4? (PDF, 271 kib)	FrOSCon 2024, 17 and 18 August 2024, St. Augustin, Germany	Ger
November 2023	Das relationale Open Source Datenbank Ökosystem - IT strategische Gedanken (PDF, 496.4 kib)	DOAG 2023 Konferenz + Ausstellung: 22 November 2023, Nürnberg, Germany	Ger
November 2023	MariaDB und MySQL HA Lösungen - Ein Datenbank-Quartett im Hochverfügbarkeitsvergleich (PDF, 30.2 kib)	DOAG 2023 Konferenz + Ausstellung: 21 November 2023, Nürnberg, Germany	Ger
November 2023	Upgrade MySQL 5.7 Galera Cluster auf MySQL 8.0 (PDF, 132.7 kib)	Galera Webinar, 17 November 2023, Webinar, DACH	Ger
May 2023	Galera Cluster for MySQL and Master/Slave Replication (PDF, 300.1 kib)	Datenbank-Tage 2023, 24 and 25 May 2023, virtual in Frankfurt, Germany	Ger
May 2023	MariaDB - aber sicher! (PDF, 1.1 Mib)	Secure Linux Administration Converence (SLAC) 2023, 23 to 25 May 2023, Berlin, Germany	Ger
September 2022	Galera Cluster for MySQL and Master/Slave Replication (PDF, 223 kib), MySQL Point-in-Time-Recovery (PiTR) (PDF, 154 kib)	DOAG 2022 Konferenz + Ausstellung, 20 to 23 September 2022, Nürnberg, Germany	Ger
March 2022	MariaDB Galera Cluster and M/S replication (PDF, 352 kib)	Chemnitzer Linux-Tage, 12 and 13 March 2022, virtual in Chemnitz, Germany	Ger
February 2022	MariaDB Connection ID (PDF, 301 kib), MariaDB Galera Cluster and M/S replication (PDF, 239 kib), MariaDB Point-in-Time-Recovery (PDF, 168 kib)	FOSDEM 2022, 5/6 February 2022, virtual in Brussels, Belgium	Eng
November 2021	MySQL Security (PDF, 266 kib)	DOAG 2021 Conference and Expo, 16 - 18 November 2021, virtual in Nuremberg, Germany	Ger
February 2021	Mariabackup - too rarely used (PDF, 226 kib)	FOSDEM 2021, MariaDB devroom, 6/7 February 2021, Brussels, remote, Belgium	Eng
December 2020	MariaDB and MySQL for Web Developers (PDF, 623 kib), Examples	Web Developer Congress 2020, 18 - 20 December 2020, remote, DACH	Ger
November 2020	MariaDB / MySQL Stolperfallen - und wie komme ich da wieder raus? (PDF, 695 kib)	DOAG Konferenz und Expo, 19 November 2020, remote in Nürnberg, Germany	Ger
October 2020	MariaDB / MySQL Stolperfallen und wie komme ich da wieder raus? (PDF, 768 kib)	GNU/LinuxDay in Vorarlberg, 10 October 2020, Dornbirn (remote), Austria	Ger
March 2020	Migration Workshop PXC 5.5 to MariaDB 10.4 (PDF, 445 kib)	Customer Event, March 2020, Paris, France	Eng
December 2019	MariaDB 10.4 New Features (PDF, 443 kib)	IT-Tage 2019, 9 - 12 December 2019, Frankfurt, Germany	Ger
November 2019	MariaDB 10.4 New Features (PDF, 399 kib)	DOAG K + A 2019, 19 - 21 November 2019, Nürnberg, Germany	Ger
November 2018	MySQL 8.0 New Features (PDF, 393 kib), MariaDB 10.3 - MySQL with PL/SQL (PDF, 518 kib)	DOAG K + A 2018, 20 - 22 November 2018, Nürnberg, Germany	Ger
May 2018	MariaDB 10.2 - New Features (PDF, 1.6 Mib)	SLAC 2018, 7 - 9 May 2018, Berlin, Germany	Ger
March 2018	MariaDB 10.2 - New Features (PDF, 683 kib)	Chemnitzer Linux-Tage 2018, 11 March 2018, Chemnitz, Germany	Ger
November 2017	MySQL Query Tuning (PDF, 2.2 Mib), MySQL Replication and GTID (PDF, 293 kib), Wenn rwx für ugo zu ungenau ist - SELinux und AppArmor (PDF, 291 kib)	DOAG K + A 2017, 21 - 23 November 2017, Nürnberg, Germany	Ger
August 2017	Wenn rwx für ugo zu ungenau ist - SELinux und AppArmor (PDF, 303 kib)	FrOSCon 2017, 19 - 20 August 2017, St.Augustin, Germany	Ger
July 2017	Wenn rwx für ugo zu ungenau ist - SELinux und AppArmor (PDF, 280 kib)	Admin-Runde, 6 July 2017, Berlin, Germany	Ger
March 2017	Katastrophenschutz durch Backup - auch privat (PDF, 1.1 Mib), Wenn rwx für ugo zu ungenau ist - SELinux und AppArmor (PDF, 265 kib)	Chemnitzer Linux-Tage 2017, 11 + 12 March 2017, Chemnitz, Germany	Ger
December 2016	MySQL/MariaDB für nicht-MySQL DBAs (PDF, 491 kib)	IT-Tage 2016, 15 December 2016, Frankfurt, Germany	Ger
November 2016	MySQL Security für Oracle DBAs (PDF, 480 kib), MySQL HA vs HA (PDF, 358 kib), Einführung in das Tuning von MySQL (PDF, 421 kib), MySQL 5.7: JSON und GIS (PDF, 1.9 Mib)	DOAG K + A 2016, 15 -17 November 2016, Nürnberg, Germany	Ger
September 2016	MySQL Database Scalability (PDF, 300 kib)	Nextcloud Conference 2016, 16 - 22 September 2016, Berlin, Germany	Eng
August 2016	ClickHouse Column Store (PDF, 943 kib), Vergleich von Replikation und Galera Cluster (PDF, 633 kib), MySQL-Auswahl auch gegen die Distribution (PDF, 407 kib), Der DB-Backup ist gemacht - was nun? (PDF, 419 kib), MySQL 5.7, JSON und GIS (PDF, 1.3 Mib), MySQL 5.7: Migration und Sicherheit (PDF, 1.6 Mib)	FrOSCON 2016, 20 - 21 August 2016, St. Augustin, Germany	Ger
July 2016	MySQL 5.7 New Features (PDF, 980 kib)	DOAG Webinar, 8 July 2016, Webinar	Ger
June 2016	MySQL für Oracle DBAs (PDF, 3.35 Mib), MySQL Beispiele aus der Praxis - Wie setzen Kunden MySQL ein? (PDF, 3.3 Mib)	SOUG DAY 2016, 23 June 2016, Baden-Dättwil, Switzerland	Ger
June 2016	Sicherheitsrelevante Änderungen (und einige andere) in MySQL 5.7 (PDF, 289 kib)	SLAC 2016, 15 - 17 June 2016, Berlin, Germany	Ger
May 2016	MySQL für Oracle DBAs (PDF, 991 kib)	DOAG 2016 Datenbank, 10 May 2016, Düsseldorf, Germany	Ger
April 2016	MySQL Servers Working as a Team - Replication or Galera Cluster (PDF, 631 kib)	Open Source Data Center Conference (OSDC), 27 April 2016, Berlin, Germany	Eng
March 2016	RPM-Konventionen - ein moderner Turm von Babel (PDF, 384 kib)	Chemnitzer Linux-Tage 2016, 20 March 2016, Chemnitz, Germany	Ger
March 2016	MySQL 5.7 New Features (PDF, 990 kib)	CeBIT 2016, 14 March 2016, Hannover, Germany	Ger
January 2016	PERFORMANCE_SCHEMA and sys schema - What can we do with it? (PDF, 406 kib)	FOSDEM 2016, 29/30 January 2016, Brussels, Belgium	Eng
January 2016	MySQL für Oracle DBA’s (PDF, 1.7 Mib), MySQL Backup/Recovery (PDF, 348 kib)	DOAG Regionaltreffen Freiburg/Südbaden, 26 January 2016, Freiburg, Germany	Ger
January 2016	MySQL-Server im Teamwork - Replikation und Cluster (PDF, 631 kib)	Admin-Runde, 7 January 2016, Berlin, Germany	Ger
December 2015	MySQL Beispiele aus der Praxis - Wie setzen Kunden MySQL ein? (PDF, 3.3 Mib)	DOAG Regionaltreffen Nürnberg/Franken, 17 December 2015, Nürnberg, Germany	Ger
November 2015	MySQL Performance Tuningfür Oracle-DBA’s (PDF, 680 kib), Der Datenbank-Backup ist gemacht - was nun ? (PDF, 415 kib), MySQL-Server im Teamwork - Replikation und Cluster (PDF, 456 kib), Weltweite Produktionsdatenverwaltung mit MySQL-Replikation (PDF, 625 kib)	DOAG Conference 2015, 17 - 19 November 2015, Nürnberg, Germany	Ger
September 2015	MySQL-Server im Teamwork (PDF, 395 kib), MySQL Replikation und Galera Cluster im Überblick	DOAG Regionaltreffen München, 28 September 2015, Munich, Germany	Ger
June 2015	Der Datenbank-Backup ist gemacht - was nun? (PDF, 743 kib), Recovery testen und dann als Produktiv-Kopie nutzen, MySQL sicher aufsetzen und betreiben (PDF, 863 kib)	SLAC 2015, 24 - 26 June 2015, Berlin, Germany	Ger
April 2015	MySQL für Oracle DBA’s (PDF, 890 kib)	DOAG Regionaltreffen Stuttgart, 1 April 2015, Stuttgart, Germany	Ger
March 2015	MySQL Performance Tuning für Entwickler (PDF, 961 kib)	Chemnitzer Linux-Tage 2015, 21/22 March 2015, Chemnitz, Germany	Ger
March 2015	MySQL für Oracle DBA’s (PDF, 1006 kib)	SOUG GV 2015 + SIG, 19 March 2015, Baden-Dättwil, Switzerland	Ger
March 2015	MySQL Performance Tuning für Entwickler (PDF, 755 kib)	CeBIT 2015, 16 March 2015, Hannover, Germany	Ger
January 2015	MySQL Replikation - Die Eier legende Wollmilchsau? (PDF, 1.2 Mib)	DOAG Webinar, 9 January 2015, Webinar	Ger
November 2014	Konsolidieren von MySQL Landschaften (PDF, 438.0 kib), Backup und Point-in-Time-Recovery mit MySQL (PDF, 183.8 kib)	DOAG Conference 2014, 18 - 20 November 2014, Nürnberg, Germany	Ger
November 2014	GTID Replication Implementation and Troubleshooting (PDF, 175.6 Mib)	Percona Live London 2014, November 3-4, 2014, London, UK.	Eng
September 2014	High-availability with Galera Cluster for MySQL (PDF, 277 kib), Reading MySQL fingerprints (PDF, 161 kib), What is a Backup Good For? (PDF, 51 kib) & How to implement GTID Replication? (PDF, 99 kib)	FromDual Company Meeting 2014, September 10 - 12, Barcelona, Spain/Catalonia	Eng
May 2014	MySQL always-up with Galera (PDF, 438 kib)	SLAC 2014, May 14 2014, Berlin, Germany	Ger
May 2014	High-availability with Galera Cluster for MySQL (PDF, 313 kib)	LinuxTag 2014, May 10 2014, Berlin, Germany	Ger
March 2014	Need for Speed: MySQL Indexing (PDF, 1.1 Mib)	CeBIT 2014, March 11 2014, Hannover, Germany	Ger
November 2013	MySQL Backup (PDF, 315 kib), MySQL Cluster with Galera (PDF, 297 kib)	DOAG Conference 2013, November 10-12 2013, Nürnberg, Germany	Ger
November 2013	Need for Speed: MySQL Indexing (PDF, 977 kib)	Percona Live London 2013, November 11-12, 2013, London, UK	Eng
October 2013	Simple usage of Xtrabackup tool (PDF, 107.8 kib), Galera Cluster for MySQL (PDF, 325 kib)	FromDual annual company Meeting, October 9, 2013, Leoforos Vravronos, Greece	Eng
June 2013	MySQL for Oracle DBAs (PDF, 331 kib)	MySQL für Oracle DBAs, June 14 2013, Online	Ger
June 2013	MySQL HA and Security (PDF, 719 kib)	SLAC 2013, June 5 to 7 2013, Berlin, Germany	Ger
May 2013	MySQL Security (PDF, 295 kib), MySQL High-Availability (PDF, 244 kib)	DOAG 2013 Datenbank, May 14 2013, Düsseldorf, Germany	Ger
March 2013	MySQL Performance Tuning (PDF, 633 kib)	Frankfurter Datenbanktage 2013, March 13 to 15 2013, Oberems-Glashütten, Germany	Ger
February 2012	Synchronous multi-Master Replication for MySQL (PDF, 134 kib), MySQL Replication: New Features in 5.5 and 5.6 (PDF, 490 kib)	DOAG SIG MySQL, February 27 2013, Munich, Germany	Ger
November 2012	Data Warehouse (DWH) with MySQL (PDF, 1.3 Mib), MySQL New Features 5.6 (PDF, 474 kib), MySQL Replication (PDF, 451 kib)	DOAG Conference 2012, November 20-22 2012, Nürnberg, Germany	Ger
August 2012	We build a Data Warehouse with MySQL (PDF, 1.3 Mib)	FrOSCon 2012, August 25-26 2012, St. Augustin, Germany	Ger
March 2012	MySQL Configuration - the most important parameters (PDF, 727 kib), Indexing with MySQL (PDF, 520 kib)	DOAG SIG MySQL - Performance, March 13 2012, Wiesbaden, Germany	Ger
February 2012	New Features in MySQL 5.6 (PDF, 459 kib), MySQL synchronous replication in practice with Galera (PDF, 176 kib)	FOSDEM 2012 at MySQL and Friends Devroom, February 5 2012, Brussels, Belgium	Eng
December 2011	HandlerSocket und ähnliche Architekturen, NoSQL für MySQL (PDF, 524 kib)	Internet Briefing Developer Conference 2011, December 8 2011, Zürich, Switzerland	Ger
December 2011	MySQL Architectures for Oracle DBA’s (PDF, 700 kib), Practical MySQL Tuning (PDF, 796 kib)	UK Oracle User Group (UKOUG) Conference 2011, December 5-7 2011, Birmingham, UK	Eng
November 2011	MySQL Performance Tuning (PDF, 811 kib), MySQL Replication for Beginners (PDF, 503 kib)	DOAG Conference 2011, November 15 - 17 2011, Nürnberg, Germany	Ger
October 2011	Various MySQL High Availability (HA) Solutions (PDF, 234 kib)	Percona Live MySQL Conference, October 24 - 25 2011, London, UK	Eng
August 2011	MySQL Performance Tuning (PDF, 693 kib), MySQL Replication for Beginners (PDF, 380 kib)	FrOSCon 2011, August 20-21 2011, St. Augustin, Germany	Ger
June 2011	DB-Programming in a different way: HandlerSocket and similar Technologies - NoSQL for MySQL (PDF, 448 kib)	DOAG SIG Development, June, 9^th 2011, Kassel, Germany	Ger
May 2011	HA Architectures with MySQL (PDF, 228 kib)	DOAG SIG Database MySQL, May, 19^th 2011, Hanover, Germany	Ger
April 2011	HandlerSocket und ähnliche Architekturen, NoSQL für MySQL (PDF, 897 kib)	Grazer Linuxtage 2011 April 9^th 2011, Graz, Austria	Ger
March 2011	MySQL Replication - Scale-Out, Master-Master, Backup (PDF, 381 kib)	DOAG Regionaltreffen München March 23^rd 2011, Munich, Germany	Ger
February 2011	HandlerSocket and similar architectures - NoSQL for MySQL (PDF, 880 kib)	FOSDEM 2011, Brussels, Belgium	Eng
November 2010	MySQL Architectures for Oracle DBA’s (PDF, 479 kib)	DOAG Conference 2010, Nürnberg, Germany	Ger
August 2010	MySQL Performance Monitoring with Zabbix (PDF, 2.1 Mib)	OpenSQL Camp EU 2010 / FrOSCon, St. Augustin, Germany	Ger
March 2010	MySQL, where are you going? (PDF, 171 kib)	OpenExpo, Bern, Switzerland	Eng
March 2010	Performance Tuning & Scale-Out mit MySQL (PDF, 339 kib)	Internet Briefing, Zürich, Switzerland	Ger
September 2007	MySQL High-Availability and Scale-Out architectures (PDF, 547 kib)	/ch/open Workshop-Tage, Zürich, Switzerland	Eng
September 2007	MySQL Performance Tuning (PDF, 834 kib)	/ch/open Workshop-Tage, Zürich, Switzerland	Eng
August 2007	Locality of (P)reference (PDF, 467 kib)	MySQL PS EMEA Meeting, Budapest, Hungary	Eng

If you want us to have a talk at your conference or event please let us know.

MariaDB, Galera, MySQL and PostgreSQL Services

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 04 Nov 2009 22:59:07 +0100

Neutral and vendor independent
MariaDB, Galera Cluster, MySQL, Percona Server and PostgreSQL
Consulting and Services!

Recovering PostgreSQL Data When Blocks Are Corrupted

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 01 Sep 2026 10:12:00 +0200

As part of our work on “PostgreSQL for Dolphins and Sea Lions,” I also enjoy reading the PostgreSQL mailing lists to see what kinds of problems come up and how they’re solved.

Making the PostgreSQL Documentation Even Better

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 11 Aug 2026 08:40:00 +0200

While working on our project “PostgreSQL for Dolphins and Sea Lions,” I pored over the PostgreSQL documentation on replication.

Artificially Delayed Replication with PostgreSQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 03 Aug 2026 09:53:00 +0200

While working on our project titled “PostgreSQL for Dolphins and Sea Lions,” I pored over the PostgreSQL documentation on replication. What struck me was that PostgreSQL does NOT support artificially delayed replication—at least according to this documentation.

PostgreSQL Point-in-Time Recovery with Oops-Queries

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 22 Jul 2026 17:26:00 +0200

While working on the topic “PostgreSQL for Dolphins and Sea Lions,” I discovered that in the PostgreSQL universe, the topic of point-in-time recovery tends to be sidestepped when it comes to specific statements or transactions. And when examples are provided, they primarily focus on DDL statements rather than DML statements.

Database Index Optimizer

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 15 Jul 2026 16:55:00 +0200

Recently, a client asked me if the “time-consuming” task of checking indexes could be left to an index optimizer. Of course it can…

MariaDB shortens maintenance period from 5 to 3 years

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 11 Jun 2026 09:34:00 +0200

Somehow this news slipped past me: MariaDB has shortened the support period for the long-term releases of the MariaDB Community Server from 5 to 3 years. OK, I guess that’s not really surprising — I’ve been offline for a good month…

What is the quickest way to load data into the database?

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 11 Feb 2026 10:04:00 +0100

We had some really exciting problems to solve for the last customer! Especially because the database wasn’t exactly small.

How much space does NULL need?

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sun, 08 Feb 2026 16:15:00 +0100

The last time I consulted a customer, he came up to me beaming with joy and said that he had taken my advice and changed all the primary key columns from BIGINT (8 bytes) to INT (4 bytes) and that had made a big difference! His MySQL 8.4 database is now 750 Gbyte smaller (from 5.5 Tbyte). Nice!

Someone is deleting my shared memory segments!

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sun, 08 Feb 2026 06:27:00 +0100

When we work with PostgreSQL under our myEnv, we regularly get shared memory segment errors. Example:

Load CSV files into the database

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 06 Feb 2026 18:04:00 +0100

Recently, I wanted to display the places of residence of the members of my club on a map for a personal gimmick (IGOC members). I knew the addresses of the club members. But not the coordinates of their places of residence.

Support policy for MariaDB, MySQL and PostgreSQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 23 Dec 2014 15:46:54 +0100

Distribution maintenance policies
MariaDB Lifetime Support Matrix for MariaDB Releases
MariaDB Corp Enterprise Support Subscriptions
MySQL Lifetime Support Matrix for MySQL Releases
Oracle Corp Enterprise Support Subscriptions for MySQL
PostgreSQL Versioning Policy
Database Support by FromDual

Distribution maintenance policies

Maintenance policies for Long Term Support (LTS) releases of common distributions: