Copyright (c) 2016, Postgres Professional

Copyright (c) 2016-2017, Postgres Professional

Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and this paragraph and the following two paragraphs appear in all copies.

OBJS = aqo.o auto_tuning.o cardinality_estimation.o cardinality_hooks.o\

hash.o machine_learning.o path_utils.o postprocessing.o preprocessing.o\

selectivity_cache.o storage.o utils.o$(WIN32RES)

REGRESS = aqo_disabled aqo_controlled aqo_intelligent aqo_forced

REGRESS = aqo_disabled aqo_controlled aqo_intelligent aqo_forced aqo_learn

MODULE_big = aqo

Note that the extensionworks bad with dynamically generated views. If they

Note that the extensiondoesn't work with dynamically generated views. If they

appear in workload, please use`aqo.mode='controlled'`.

This extension has intelligent self-tuning mode. If you want to rely completely

where`file_with_sql_queries.sql` is a textfile with queries on which AQO is

supposed to learn. Please use only`SELECT` queries in

file_with_sql_queries.sql.

More sophisticated and convenient tool for AQO administration is in the

development now.

Another way to use AQO for the specified query structure type is

`aqo.mode = 'learn'`. In this mode AQO is enabled without self-tuning for all

queries. So one can use`'controlled'` mode, then switch to`'learn'` mode,

run a query to optimize and switch back to`'controlled'`.

`'learn'` mode is not recommended to be used permanently for the whole cluster,

because it enables AQO for every query type, even for those ones that don't need

it, and that may lead to unnecessary computational overheads and performance

degradation.

If you want to freeze optimizer's behavior (i. e. disable learning under

workload), use`UPDATE aqo_queries SET auto_tuning=false;`.

workload), use`UPDATE aqo_queries SETlearn_aqo=false,auto_tuning=false;`.

If you want to disable AQO for all queries, you may use

`UPDATE aqo_queries SET use_aqo=false, learn_aqo=false, auto_tuning=false;`.

sometimes because of cost models incompleteness.

Learn_aqo setting shows whether AQO collects statistics for next execution of

such query type.True value may have computational overheads, but it is

such query type.Enabled value may have computational overheads, but it is

essential when AQO model does not fit the data. It happens at the start of AQO

for the new query type or when the data distribution in database is changed.

{"intelligent",AQO_MODE_INTELLIGENT, false},

{"forced",AQO_MODE_FORCED, false},

{"controlled",AQO_MODE_CONTROLLED, false},

{"learn",AQO_MODE_LEARN, false},

{"disabled",AQO_MODE_DISABLED, false},

{NULL,0, false}

};

#error "Cannot build aqo with PostgreSQL version lower than 9.6.0"

{

AQO_MODE_INTELLIGENT,

AQO_MODE_FORCED,

AQO_MODE_CONTROLLED,

AQO_MODE_LEARN,

AQO_MODE_DISABLED,

}AQO_MODE;