sr_plan looks like Oracle Outline system. It can be used to lock the execution plan. It is necessary if you do not trust the planner or able to form a better plan.

Dependencies: >= Python 3.2, Mako, pycparser

If you only have a Python you can use the virtual environment:

virtualenv env

source ./env/bin/activate

pip install -r ./requirements.txt

Then you need to generate C code and compiled it:

make USE_PGXS=1 genparser

make USE_PGXS=1

make USE_PGXS=1 install

and modify your postgres config:

In your db:

CREATE EXTENSION sr_plan;

If you want to save the query plan is necessary to set the variable:

set sr_plan.write_mode = true;

Now plans for all subsequent queries will be stored in the table sr_plans. Don't forget that all queries will be stored including duplicates.

Making an example query:

select query_hash from sr_plans where query_hash=10;

disable saving the query:

set sr_plan.write_mode = false;

Now verify that your query is saved:

select query_hash, enable, valid, query, explain_jsonb_plan(plan) from sr_plans;

query_hash | enable | valid | query | explain_jsonb_plan

1783086253 | f | t | select query_hash from sr_plans where query_hash=10; | Bitmap Heap Scan on sr_plans +

| | | | Recheck Cond: (query_hash = 10) +

| | | | -> Bitmap Index Scan on sr_plans_query_hash_idx+

| | | | Index Cond: (query_hash = 10) +

| | | |

explain_jsonb_plan function allows you to display explain execute the plan of which lies in jsonb. By default, all the plans are off, you need enable it:

update sr_plans set enable=true where query_hash=1783086253;

(1783086253 for example only)

After that, the plan for the query will be taken from the sr_plans.

In addition sr plan allows you to save a parameterized query plan. In this case, we have some constants in the query are not essential.

For the parameters we use a special function _p (anyelement) example:

select query_hash from sr_plans where query_hash=1000+_p(10);

if we keep the plan for the query and enable it to be used also for the following queries:

select query_hash from sr_plans where query_hash=1000+_p(11);

select query_hash from sr_plans where query_hash=1000+_p(-5);