Schedule - PGConf NYC 2022

Tale of the PostgreSQL TOAST Tables

Date: 2022-09-22
Time: 15:45–16:35
Room: The Library
Level: Intermediate
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PostgreSQL’s default page size is 8 KB, and it does not allow row/tuple to span multiple pages. TOAST (The Oversized-Attribute Storage Technique) is a mechanism PostgreSQL uses to keep tuple from exceeding the size of a default page size, so the block size is a hard upper limit on row size. To allow user tables to have rows wider than this, the TOAST mechanism breaks up wide field values into smaller pieces, which are stored "out of line" in a TOAST table associated with the user table.

In this presentation, we will show various aspects of the TOAST tables, the storage options for storing TOAST tables, and the impact on the performance on text size of the column. We also cover how to query information related to TOAST tables from PostgreSQL metadata.

In this session, Shailesh will cover:

• Introduction to TOAST table mechanism

• TOAST table storage strategy options

• Optimizing query time with the TOAST table storage strategy

• How to find information about TOAST tables using PostgreSQL metadata

• Impact of Texts Size on PostgreSQL Performance


Shailesh Rangani