Database Reference
In-Depth Information
•
checkpoint_timeout
: This parameter too is used to control the checkpoints,
that is, a checkpoint occurs when
checkpoint_timeout
log seconds have
passed. The default value is 5 minutes. The following statement shows the
default value of
checkpoint_timeout
:
warehouse_db=# SHOW checkpoint_timeout;
checkpoint_timeout
--------------------
5min
(1 row)
•
shared_buffers
: The
shared_buffers
parameter is used to limit the
memory dedicated to caching of data in PostgreSQL. The default value is 128
MB. The following statement shows the default value of
shared_buffers
:
warehouse_db=# SHOW shared_buffers;
shared_buffers
----------------
128MB
(1 row)
Summary
This chapter has taken you to an advanced level, which will help you acquire the
necessary database skillset to debug the queries with
EXPLAIN
and understand the
different ways of optimizing the query using output of
EXPLAIN
,
EXPLAIN ANALYZE
and
VERBOSE
. Use of joins, hash, and merge joins were touched upon as well. You
should be practicing the coniguration parameters covered here to see performance
statistics and the impact on I/O operations.
In the next chapter, we will discuss how PostgreSQL handles large objects and most
importantly how to import and export them with the help of some examples.
