LSA2 - PostgreSQL
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This document discusses PostgreSQL, including its directory structure, on-disk data structure with tables stored in separate files, configuration involving authentication and server settings, and working with PostgreSQL through tools like psql and phpPgAdmin. It also covers backup and restore methods like pg_dump and monitoring the server, tables, and indexes.
LSA2 - PostgreSQL
- 1. DataBases - PostgreSQL Linux System Administration II Marian Marinov Linux System Administration II DataBases - PostgreSQL
- 2. Important links http://www.postgresql.org PostgreSQL 9.3 Documentation PostgreSQL Wiki pgFoundry projects pg-as-nosql-pgday-fosdem-2013.pdf Linux System Administration II DataBases - PostgreSQL
- 3. Installation Source RPM/DEB Linux System Administration II DataBases - PostgreSQL
- 4. Directory structure basic /var/lib/pgsql/data/* Debian based /etc/postgresql-common/ /etc/postgresql/9.3/main/ /var/lib/postgresql/9.3/main/ RedHat based old versions /var/lib/pgsql/data/* newer versions /var/lib/pgsql/9.3/data/* Linux System Administration II DataBases - PostgreSQL
- 5. Structure of PostgreSQL server prefork (shared memory) client handling (client library) query parser query analyzer query planner plug-in modules storage engine maintenance processes client client library parser autocomplete Linux System Administration II DataBases - PostgreSQL
- 6. On disk data structure | |- PG_VERSION |- base per-database subdirectories |- global cluster-wide tables, such as pg_database |- pg_clog transaction commit status data |- pg_multixact multitransaction status data |- pg_stat_tmp temporary files for the statistics subsyste |- pg_subtrans subtransaction status data |- pg_tblspc symbolic links to tablespaces |- pg_twophase state files for prepared transactions |- pg_xlog WAL (Write Ahead Log) files |... Linux System Administration II DataBases - PostgreSQL
- 7. On disk data structure base - |- 1 |- 11510 |- 11511 |- 16384 - 24576 template1=# SELECT datname,datlastsysoid FROM pg_database; datname | datlastsysoid -------------+---------------- template1 | 11510 template0 | 11510 postgres | 11510 os | 11510 (5 rows) Linux System Administration II DataBases - PostgreSQL
- 8. On disk data structure base - |- 11510 - | |- 24765 os# SELECT relname,relfilenode,reltablespace FROM pg_class WHERE relfilenode=24765; Relname | relfilenode | reltablespace ------------+---------------+--------------- disk_io | 24765 | 0 (1 row) Linux System Administration II DataBases - PostgreSQL
- 9. On disk data structure Table and Indexes are stored in separate files Tables bigger then 1GB are split into different files: filenode.1, filenode.2, . . . , filenode.N The 1GB limit can be changed during build using –with-segsize configure option. Linux System Administration II DataBases - PostgreSQL
- 10. DataBase Design DBNAME SCHME OBJECTS database - (table/view/sequence/domain) |- public |- scheme1 ----- | |- table1 | |- table2 | |- view1 | |- view2 | |- seq1 | - seq2 - scheme2 Linux System Administration II DataBases - PostgreSQL
- 11. Configuration authentication (pg hba.conf) server (postgresql.conf) storage considerations Linux System Administration II DataBases - PostgreSQL
- 12. Working with PgSQL (psql and phpPgAdmin) start/stop/restart/reload the server server resouce limits(ulimits) kernel tunning for PgSQL Linux System Administration II DataBases - PostgreSQL
- 13. Working with PgSQL (psql and phpPgAdmin) storage types standard types XML/JSON Network datatypes PostGIS ARRAYs User defined types (UDT) tablespaces list databases list users grant/revoke privileges creating/destroying users creating/destroying databases creating/destroying schemas creating/destroying tables Linux System Administration II DataBases - PostgreSQL
- 14. Working with PgSQL (psql and phpPgAdmin) creating/destroying constrains creating/destroying indexes creating/destroying sequences VACUUM/AUTOVACUUM VACUUM vs. ANALYZE built-in functions writing user functions adding a language to a database supported languages (SQL, pl/pgSQL, PL/Python, PL/Perl, PL/TCL, pl/V8, PL/R, PL/LUA, C) adding an extension to a database Foreign data wrappers Linux System Administration II DataBases - PostgreSQL
- 15. Backup and restores pg dump pg dumpall LVM snapshots Via replication WAL Linux System Administration II DataBases - PostgreSQL
- 16. Monitoring EXPLAIN ( Planner Cost Constants ) ps axf. . . monitoring server monitoring tables & indexes Linux System Administration II DataBases - PostgreSQL