Changes between Version 18 and Version 19 of Performance


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Timestamp:
Nov 4, 2013, 2:06:36 PM (11 years ago)
Author:
miracee
Comment:

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  • Performance

    v18 v19  
    141141* In PostgreSQL version >= 9.2 you need to cast relpages to NUMERIC because the function changed to pg_size_pretty(NUMERIC).
    142142
     143* Tables and indexes starting with pg_ usually are tables created by the postgresql system
     144* pg_largeobject belongs to the tables created by postgresql
     145* oid for objects created by the postgresql system are lower then the database oid
     146* oid from your own tables and indexes always are bigger then the database oid
     147
     148When you just want to list all your own tables and indexes plus the toast tables that were created for that tables / indexes:
     149{{{
     150... WHERE oid > DATABASE_OID;
     151}}}
     152
     153When you want to get informations about pg_largobject:
     154{{{
     155... WHERE relname LIKE '%large%';
     156}}}
     157
     158=== TOAST ===
     159
     160* The Oversize Attribute Storage Technique
     161* Used on variable length data types (e.g. varchar, text, bytea)
     162** PostgreSQL creates pg_toast_* tables here which are empty as long as data won't exceed page size
     163* If tuple exceeds page size (8 kB by default)
     164** data will get compressed
     165** data will be broken into multiple rows
    143166
    144167== Size of RASBASE tables ==