external
/
pg_stat_monitor
mirror of https://github.com/percona/pg_stat_monitor.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Update README.md

pull/64/head
Ibrar Ahmed 2020-11-25 03:46:05 +05:00 committed by GitHub
parent 4bcd70b7d5
commit aac68f95f2
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 10 additions and 349 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

359
README.md
View File

@ -1,6 +1,15 @@
## What is pg_stat_monitor? ## What is pg_stat_monitor?
The pg_stat_monitor is the statistics collection tool based on PostgreSQL's contrib module ``pg_stat_statements``. PostgreSQL’s pg_stat_statements provides the basic statistics, which is sometimes not enough. The major shortcoming in pg_stat_statements is that it accumulates all the queries and their statistics and does not provide aggregated statistics nor histogram information. In this case, a user needs to calculate the aggregate which is quite expensive. ``pg_stat_monitor`` is developed on the basis of pg_stat_statements as its more advanced replacement. It provides all the features of pg_stat_statements plus its own feature set. The pg_stat_monitor is the statistics collection tool based on PostgreSQL's contrib module ``pg_stat_statements``. PostgreSQL’s pg_stat_statements provides the basic statistics, which is sometimes not enough. The major shortcoming in pg_stat_statements is that it accumulates all the queries and their statistics and does not provide aggregated statistics nor histogram information. In this case, a user needs to calculate the aggregate which is quite expensive. ``pg_stat_monitor`` is developed on the basis of pg_stat_statements as its more advanced replacement. It provides all the features of pg_stat_statements plus its own feature set.
## Documentation
1. [Supported PostgreSQL Versions](#supported-postgresql-versions)
2. [Installation](#installation)
3. [Setup](#setup)
4. [User Guide](https://github.com/percona/pg_stat_monitor/blob/master/docs/USER_GUIDE.md)
6. [Release Notes](https://github.com/percona/pg_stat_monitor/blob/master/docs/RELEASE_NOTES.md)
7. [License](https://github.com/percona/pg_stat_monitor/blob/master/LICENSE)
8. [Copyright Notice](#copyright-notice)
## Supported PostgreSQL Versions ## Supported PostgreSQL Versions
The ``pg_stat_monitor`` should work on the latest version of PostgreSQL but is only tested with these PostgreSQL versions: The ``pg_stat_monitor`` should work on the latest version of PostgreSQL but is only tested with these PostgreSQL versions:
@ -15,13 +24,6 @@ The ``pg_stat_monitor`` should work on the latest version of PostgreSQL but is o
| Percona Distribution | Version 12 | :heavy_check_mark: | | Percona Distribution | Version 12 | :heavy_check_mark: |
| Percona Distribution | Version 13 | :heavy_check_mark: | | Percona Distribution | Version 13 | :heavy_check_mark: |
## Documentation
1. [Installation](#installation)
2. [Setup](#setup)
3. [Configuration](#configuration)
4. [User Guide](#user-guide)
5. [License](#license)
## Installation ## Installation
There are two ways to install ``pg_stat_monitor``: There are two ways to install ``pg_stat_monitor``:
@ -86,347 +88,6 @@ postgres=# create extension pg_stat_monitor;
CREATE EXTENSION CREATE EXTENSION
``` ```
After doing that change, we need to restart the PostgreSQL server. PostgreSQL will start monitoring and collecting the statistics. ## Copyright Notice
## Configuration
Here is the complete list of configuration parameters.
```sql
postgres=# select * from pg_stat_monitor_settings;
name | value | default_value | description | minimum | maximum | restart
-----------------------------------------------+--------+---------------+-------------------------------------------------------------------+---------+------------+---------
pg_stat_monitor.pgsm_max | 5000 | 5000 | Sets the maximum number of statements tracked by pg_stat_monitor. | 5000 | 2147483647 | 1
pg_stat_monitor.pgsm_query_max_len | 1024 | 1024 | Sets the maximum length of query. | 1024 | 2147483647 | 1
pg_stat_monitor.pgsm_enable | 1 | 1 | Enable/Disable statistics collector. | 0 | 0 | 1
pg_stat_monitor.pgsm_track_utility | 1 | 0 | Selects whether utility commands are tracked. | 0 | 0 | 0
pg_stat_monitor.pgsm_normalized_query | 1 | 0 | Selects whether save query in normalized format. | 0 | 0 | 0
pg_stat_monitor.pgsm_max_buckets | 10 | 10 | Sets the maximum number of buckets. | 1 | 10 | 1
pg_stat_monitor.pgsm_bucket_time | 60 | 60 | Sets the time in seconds per bucket. | 1 | 2147483647 | 1
pg_stat_monitor.pgsm_respose_time_lower_bound | 1 | 1 | Sets the time in millisecond. | 1 | 2147483647 | 1
pg_stat_monitor.pgsm_respose_time_step | 1 | 1 | Sets the respose time steps in millisecond. | 1 | 2147483647 | 1
pg_stat_monitor.pgsm_query_shared_buffer | 500000 | 500000 | Sets the query shared_buffer size. | 500000 | 2147483647 | 1
(11 rows)
```
Some configuration parameters require the server restart and should be set before the server startup. These must be set in the ``postgresql.conf`` file. Other parameters do not require server restart and can be set permanently either in the ``postgresql.conf`` or from the client (``psql``).
The table below shows set up options for each configuration parameter and whether the server restart is required to apply its value:
| Parameter Name | postgresql.conf | SET | ALTER SYSTEM SET | server restart | configuration reload
| ----------------------------------------------|--------------------|-----|-------------------|-------------------|---------------------
| pg_stat_monitor.pgsm_max | :heavy_check_mark: | :x: |:x: |:heavy_check_mark: | :x:
| pg_stat_monitor.pgsm_query_max_len | :heavy_check_mark: | :x: |:x: |:heavy_check_mark: | :x:
| pg_stat_monitor.pgsm_enable | :heavy_check_mark: | :x: |:heavy_check_mark: |:x: | :x:
| pg_stat_monitor.pgsm_track_utility | :heavy_check_mark: | :heavy_check_mark: |:heavy_check_mark: |:x: | :heavy_check_mark:
| pg_stat_monitor.pgsm_normalized_query | :heavy_check_mark: | :heavy_check_mark: |:heavy_check_mark: |:x: | :heavy_check_mark:
| pg_stat_monitor.pgsm_max_buckets | :heavy_check_mark: | :x: |:x: |:heavy_check_mark: | :heavy_check_mark:
| pg_stat_monitor.pgsm_bucket_time | :heavy_check_mark: | :x: |:x: |:heavy_check_mark: | :x:
| pg_stat_monitor.pgsm_object_cache | :heavy_check_mark: | :x: |:x: |:heavy_check_mark: | :x:
| pg_stat_monitor.pgsm_respose_time_lower_bound | :heavy_check_mark: | :x: |:x: |:heavy_check_mark: | :x:
| pg_stat_monitor.pgsm_respose_time_step | :heavy_check_mark: | :x: |:x: |:heavy_check_mark: | :x:
| pg_stat_monitor.pgsm_query_shared_buffer | :heavy_check_mark: | :x: |:x: |:heavy_check_mark: | :x:
### Parameters description:
- **pg_stat_monitor.pgsm_max**: This parameter defines the limit of shared memory for ``pg_stat_monitor``. This memory is used by buckets in a circular manner. The memory is divided between the buckets equally, at the start of the PostgreSQL.
- **pg_stat_monitor.pgsm_query_max_len**: Sets the maximum size of the query. This parameter can only be set at the start of PostgreSQL. For long queries, the query is truncated to that particular length. This is to avoid unnecessary usage of shared memory.
- **pg_stat_monitor.pgsm_enable**: This parameter enables or disables the monitoring. "Disable" means that ``pg_stat_monitor`` will not collect the statistics for the whole cluster.
- **pg_stat_monitor.pgsm_track_utility**: This parameter controls whether utility commands are tracked by the module. Utility commands are all those other than ``SELECT``, ``INSERT``, ``UPDATE`` and ``DELETE``.
- **pg_stat_monitor.pgsm_normalized_query**: By default, query shows the actual parameter instead of the placeholder. It is quite useful when users want to use that query and try to run that query to check the abnormalities. But in most cases users like the queries with a placeholder. This parameter is used to toggle between the two said options.
- **pg_stat_monitor.pgsm_max_buckets**: ``pg_stat_monitor`` accumulates the information in the form of buckets. All the aggregated information is bucket based. This parameter is used to set the number of buckets the system can have. For example, if this parameter is set to 2, then the system will create two buckets. First, the system will add all the information into the first bucket. After its lifetime (defined in the pg_stat_monitor.pgsm_bucket_time parameter) expires, it will switch to the second bucket, reset all the counters and repeat the process.
- **pg_stat_monitor.pgsm_bucket_time**: This parameter is used to set the lifetime of the bucket. System switches between buckets on the basis of ``pg_stat_monitor.pgsm_bucket_time``.
- **pg_stat_monitor.pgsm_respose_time_lower_bound**: ``pg_stat_monitor`` also stores the execution time histogram. This parameter is used to set the lower bound of the histogram.
- **pg_stat_monitor.pgsm_respose_time_step:** This parameter is used to set the steps for the histogram.
## User Guide
| Column | Type | pg_stat_monitor | pg_stat_statments
|--------------------|--------------------------|----------------------|------------------
bucket | integer | :heavy_check_mark: | :x:
bucket_start_time | timestamp with time zone | :heavy_check_mark: | :x:
userid | oid | :heavy_check_mark: | :heavy_check_mark:
dbid | oid | :heavy_check_mark: | :heavy_check_mark:
client_ip | inet | :heavy_check_mark: | :x:
queryid | text | :heavy_check_mark: | :heavy_check_mark:
query | text | :heavy_check_mark: | :heavy_check_mark:
application_name | text | :heavy_check_mark: | :x:
relations | text[] | :heavy_check_mark: | :x:
cmd_type | text[] | :heavy_check_mark: | :x:
elevel | integer | :heavy_check_mark: | :x:
sqlcode | integer | :heavy_check_mark: | :x:
message | text | :heavy_check_mark: | :x:
plans | bigint | :heavy_check_mark: | :heavy_check_mark:
plan_total_time | double precision | :heavy_check_mark: | :heavy_check_mark:
plan_min_timei | double precision | :heavy_check_mark: | :heavy_check_mark:
plan_max_time | double precision | :heavy_check_mark: | :heavy_check_mark:
plan_mean_time | double precision | :heavy_check_mark: | :heavy_check_mark:
plan_stddev_time | double precision | :heavy_check_mark: | :heavy_check_mark:
calls | bigint | :heavy_check_mark: | :heavy_check_mark:
total_time | double precision | :heavy_check_mark: | :heavy_check_mark:
min_time | double precision | :heavy_check_mark: | :heavy_check_mark:
max_time | double precision | :heavy_check_mark: | :heavy_check_mark:
mean_time | double precision | :heavy_check_mark: | :heavy_check_mark:
stddev_time | double precision | :heavy_check_mark: | :heavy_check_mark:
rows | bigint | :heavy_check_mark: | :heavy_check_mark:
shared_blks_hit | bigint | :heavy_check_mark: | :heavy_check_mark:
shared_blks_read | bigint | :heavy_check_mark: | :heavy_check_mark:
shared_blks_dirtied | bigint | :heavy_check_mark: | :heavy_check_mark:
shared_blks_written | bigint | :heavy_check_mark: | :heavy_check_mark:
local_blks_hit | bigint | :heavy_check_mark: | :heavy_check_mark:
local_blks_read | bigint | :heavy_check_mark: | :heavy_check_mark:
local_blks_dirtied | bigint | :heavy_check_mark: | :heavy_check_mark:
local_blks_written | bigint | :heavy_check_mark: | :heavy_check_mark:
temp_blks_read | bigint | :heavy_check_mark: | :heavy_check_mark:
temp_blks_written | bigint | :heavy_check_mark: | :heavy_check_mark:
blk_read_time | double precision | :heavy_check_mark: | :heavy_check_mark:
blk_write_time | double precision | :heavy_check_mark: | :heavy_check_mark:
resp_calls | text[] | :heavy_check_mark: | :x:
cpu_user_time | double precision | :heavy_check_mark: | :x:
cpu_sys_time | double precision | :heavy_check_mark: | :x:
### Buckets
pg_stat_monitor collects and aggregates data on a bucket basis. The size of a bucket and the number of buckets should be configured using GUC (Grand Unified Configuration). When a bucket time elapses, pg_stat_monitor resets all the statistics and switches to the next bucket. After the last bucket elapses, pg_stat_monitor goes back to the first bucket. All the data on the first bucket will vanish; therefore, users must read the buckets before that to not lose the data.
**`bucket`**: Accumulates the statistics per bucket. All the information and aggregate reset for each bucket. The bucket will be a number showing the number of buckets for which this record belongs.
**`bucket_start_time`**: shows the start time of the bucket.
```sql
postgres=# select bucket, bucket_start_time, query from pg_stat_monitor;
bucket | bucket_start_time | query
--------+-------------------------------+--------------------------------------------------------
2 | 2020-05-23 13:24:44.652415+00 | select * from pg_stat_monitor_reset()
3 | 2020-05-23 13:45:01.55658+00 | select bucket, bucket_start_time, query from pg_stat_monitor
2 | 2020-05-23 13:24:44.652415+00 | SELECT * FROM foo
(3 rows)
```
### Query Information
**`userid`**: An ID of the user whom that query belongs. pg_stat_monitor is used to collect queries from all the users; therefore, `userid` is used to segregate the queries based on different users.
**`dbid`**: The database ID of the query. pg_stat_monitor accumulates queries from all the databases; therefore, this column is used to identify the database.
**`queryid`**: pg_stat_monitor generates a unique ID for each query (queryid).
**`query`**: The query column contains the actual text of the query. This parameter depends on the **`pg_stat_monitor.pgsm_normalized_query`** configuration parameters, in which format to show the query.
**`calls`**: Number of calls of that particular query.
#### Example 1: Shows the userid, dbid, unique queryid hash, query and total number of calls or that query.
```sql
postgres=# select userid, dbid, queryid, substr(query,0, 50) as query, calls from pg_stat_monitor;
userid | dbid | queryid | query | calls
--------+-------+------------------+---------------------------------------------------+-------
10 | 12709 | 214646CE6F9B1A85 | BEGIN | 1577
10 | 12709 | 8867FEEB8A5388AC | vacuum pgbench_branches | 1
10 | 12709 | F47D95C9DF863E43 | UPDATE pgbench_branches SET bbalance = bbalance + | 1577
10 | 12709 | 2FE0A6ABDC20623 | select substr(query,$1, $2) as query, cmd_type fr | 7
10 | 12709 | A83503D3E1F99139 | select userid, dbid, queryid, substr(query,$1, $ | 1
10 | 12709 | D4B1243AC3268B9B | select count(*) from pgbench_branches | 1
10 | 12709 | 2FE0A6ABDC20623 | select substr(query,$1, $2) as query, cmd_type fr | 1
10 | 12709 | 1D9BDBBCFB89F096 | UPDATE pgbench_accounts SET abalance = abalance + | 1577
10 | 12709 | 15343084284782B | update test SET a = $1 | 2
10 | 12709 | 939C2F56E1F6A174 | END | 1577
1 | 12709 | DAE6D269D27F2EC4 | SELECT FOR UPDATE test SET a = 1; | 1
10 | 12709 | 2B50C2406BFAC907 | INSERT INTO pgbench_history (tid, bid, aid, delta | 1577
10 | 12709 | F6DA9838660825CA | vacuum pgbench_tellers | 1
10 | 12709 | 3AFB8B2452721F9 | SELECT a from test for update | 1
10 | 12709 | A5CD0AF80D28363 | SELECT abalance FROM pgbench_accounts WHERE aid = | 1577
10 | 12709 | E445DD36B9189C53 | UPDATE pgbench_tellers SET tbalance = tbalance + | 1577
10 | 12709 | 4876BBA9A8FCFCF9 | truncate pgbench_history | 1
10 | 12709 | D3C2299FD9E7348C | select userid, dbid, queryid, query, calls from | 1
(18 rows)
```
#### Example 2: Shows the different username for the queries.
```
postgres=# select userid::regrole, datname, substr(query,0, 50) as query, calls from pg_stat_monitor, pg_database WHERE dbid = oid;
userid | datname | query | calls
----------+----------+---------------------------------------------------+-------
vagrant | postgres | select userid::regrole, datname, substr(query,$1, | 1
vagrant | test_db | insert into bar values($1) | 1
vagrant | postgres | insert into bar values($1) | 1
vagrant | test_db | select * from bar | 1
postgres | postgres | insert into bar values($1) | 1
(5 rows)
```
#### Example 3: Shows the differen database involved in the queries.
```
postgres=# select userid::regrole, datname, substr(query,0, 50) as query, calls from pg_stat_monitor, pg_database WHERE dbid = oid;
userid | datname | query | calls
---------+----------+---------------------------------------------------+-------
vagrant | postgres | select userid::regrole, datname, substr(query,$1, | 0
vagrant | test_db | insert into bar values($1) | 1
vagrant | test_db | select * from bar | 1
(3 rows)
```
#### Example 4: Shows the connected application_name.
```sql
postgres=# select application_name, query from pg_stat_monitor;
application_name | query
------------------+------------------------------------------------------------------------------------------------------
pgbench | UPDATE pgbench_branches SET bbalance = bbalance + $1 WHERE bid = $2
pgbench | UPDATE pgbench_accounts SET abalance = abalance + $1 WHERE aid = $2
pgbench | vacuum pgbench_tellers
pgbench | SELECT abalance FROM pgbench_accounts WHERE aid = $1
pgbench | END
pgbench | select count(*) from pgbench_branches
pgbench | BEGIN
pgbench | INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES ($1, $2, $3, $4, CURRENT_TIMESTAMP)
psql | select application_name, query from pg_stat_monitor
pgbench | vacuum pgbench_branches
psql | select application_name query from pg_stat_monitor
pgbench | truncate pgbench_history
pgbench | UPDATE pgbench_tellers SET tbalance = tbalance + $1 WHERE tid = $2
(13 rows)
```
### Error Messages / Error Codes and Error Level
**`elevel`**, **`sqlcode`**,**`message`**,: error level / sql code and log/warning/error message
```sql
postgres=# select substr(query,0,50) as query, decode_error_level(elevel)as elevel,sqlcode,calls, substr(message,0,50) message from pg_stat_monitor;
query | elevel | sqlcode | calls | message
---------------------------------------------------+--------+---------+-------+---------------------------------------------------
select substr(query,$1,$2) as query, decode_error | | 0 | 1 |
select bucket,substr(query,$1,$2),decode_error_le | | 0 | 3 |
| LOG | 0 | 1 | database system is ready to accept connections
select 1/0; | ERROR | 130 | 1 | division by zero
| LOG | 0 | 1 | database system was shut down at 2020-11-11 11:37
select $1/$2 | | 0 | 1 |
(6 rows)
```
### Query Timing Information
**`total_time`**, **`min_time`**, **`max_time`**, **`mean_time`**: The total / minimum / maximum and mean time spent for the same query.
```
postgres=# select userid, total_time, min_time, max_time, mean_time, query from pg_stat_monitor;
userid | total_time | min_time | max_time | mean_time | query
--------+--------------------+--------------------+--------------------+--------------------+------------------------------------------------------------------
10 | 0.14 | 0.14 | 0.14 | 0.14 | select * from pg_stat_monitor_reset()
10 | 0.19 | 0.19 | 0.19 | 0.19 | select userid, dbid, queryid, query from pg_stat_monitor
10 | 0.30 | 0.13 | 0.16 | 0.15 | select bucket, bucket_start_time, query from pg_stat_monitor
10 | 0.29 | 0.29 | 0.29 | 0.29 | select userid, dbid, queryid, query, calls from pg_stat_monitor
10 | 11277.79 | 11277.79 | 11277.79 | 11277.79 | SELECT * FROM foo
```
### Client IP address
**`client_ip`**: The IP address of the client that originated the query.
```sql
postgres=# select userid::regrole, datname, substr(query,0, 50) as query, calls,client_ip from pg_stat_monitor, pg_database WHERE dbid = oid;
userid | datname | query | calls | client_ip
---------+----------+---------------------------------------------------+-------+-----------
vagrant | postgres | UPDATE pgbench_branches SET bbalance = bbalance + | 1599 | 10.0.2.15
vagrant | postgres | select userid::regrole, datname, substr(query,$1, | 5 | 10.0.2.15
vagrant | postgres | UPDATE pgbench_accounts SET abalance = abalance + | 1599 | 10.0.2.15
vagrant | postgres | select userid::regrole, datname, substr(query,$1, | 1 | 127.0.0.1
vagrant | postgres | vacuum pgbench_tellers | 1 | 10.0.2.15
vagrant | postgres | SELECT abalance FROM pgbench_accounts WHERE aid = | 1599 | 10.0.2.15
vagrant | postgres | END | 1599 | 10.0.2.15
vagrant | postgres | select count(*) from pgbench_branches | 1 | 10.0.2.15
vagrant | postgres | BEGIN | 1599 | 10.0.2.15
vagrant | postgres | INSERT INTO pgbench_history (tid, bid, aid, delta | 1599 | 10.0.2.15
vagrant | postgres | vacuum pgbench_branches | 1 | 10.0.2.15
vagrant | postgres | truncate pgbench_history | 1 | 10.0.2.15
vagrant | postgres | UPDATE pgbench_tellers SET tbalance = tbalance + | 1599 | 10.0.2.15
```
### Call Timings Histogram
**`resp_calls`**: Call histogram
```sql
postgres=# select resp_calls, query from pg_stat_monitor;
resp_calls | query
--------------------------------------------------+----------------------------------------------
{1," 0"," 0"," 0"," 0"," 0"," 0"," 0"," 0"," 0"} | select client_ip, query from pg_stat_monitor
{3," 0"," 0"," 0"," 0"," 0"," 0"," 0"," 0"," 1"} | select * from pg_stat_monitor_reset()
{3," 0"," 0"," 0"," 0"," 0"," 0"," 0"," 0"," 1"} | SELECT * FROM foo
```
There are 10 timebase buckets of the time **`pg_stat_monitor.pgsm_respose_time_step`** in the field ``resp_calls``. The value in the field shows how many queries run in that period of time.
### Object Information.
**`relations`**: The list of tables involved in the query
#### Example 1: List all the table names involved in the query.
```sql
postgres=# select relations::oid[]::regclass[], query from pg_stat_monitor;
relations | query
--------------------+------------------------------------------------------------------------------------------------------
{pgbench_accounts} | UPDATE pgbench_accounts SET abalance = abalance + $1 WHERE aid = $2
{pgbench_accounts} | SELECT abalance FROM pgbench_accounts WHERE aid = $1
{pg_stat_monitor} | select relations::oid[]::regclass[], cmd_type,resp_calls,query from pg_stat_monitor
{pgbench_branches} | select count(*) from pgbench_branches
{pgbench_history} | INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES ($1, $2, $3, $4, CURRENT_TIMESTAMP)
{foo,bar} | select * from foo,bar
(5 rows)
```
#### Example 2: List all the views and the name of table in the view. Here we have a view "test_view"
```sql
postgres=# \d+ test_view
View "public.test_view"
Column | Type | Collation | Nullable | Default | Storage | Description
--------+---------+-----------+----------+---------+---------+-------------
foo_a | integer | | | | plain |
bar_a | integer | | | | plain |
View definition:
SELECT f.a AS foo_a,
b.a AS bar_a
FROM foo f,
bar b;
```
Now when we query the pg_stat_monitor, it will shows the view name and also all the table names in the view.
```sql
postgres=# select relations::oid[]::regclass[], query from pg_stat_monitor;
relations | query
---------------------+------------------------------------------------------------------------------------------------------
{test_view,foo,bar} | select * from test_view
{foo,bar} | select * from foo,bar
(2 rows)
```
### Query command Type (SELECT, INSERT, UPDATE OR DELETE)
**`cmd_type`**: List the command type of the query.
```sql
postgres=# select substr(query,0, 50) as query, cmd_type from pg_stat_monitor where elevel = 0;
query | cmd_type
---------------------------------------------------+-----------------
BEGIN | {INSERT}
vacuum pgbench_branches | {}
UPDATE pgbench_branches SET bbalance = bbalance + | {UPDATE,SELECT}
select substr(query,$1, $2) as query, cmd_type fr | {SELECT}
select count(*) from pgbench_branches | {SELECT}
select substr(query,$1, $2) as query, cmd_type fr | {}
UPDATE pgbench_accounts SET abalance = abalance + | {UPDATE,SELECT}
update test SET a = $1 | {UPDATE}
END | {INSERT}
INSERT INTO pgbench_history (tid, bid, aid, delta | {INSERT}
vacuum pgbench_tellers | {}
SELECT a from test for update | {UPDATE,SELECT}
SELECT abalance FROM pgbench_accounts WHERE aid = | {SELECT}
UPDATE pgbench_tellers SET tbalance = tbalance + | {UPDATE,SELECT}
truncate pgbench_history | {}
(15 rows)
```
**Copyright notice**
Copyright (c) 2006 - 2020, Percona LLC. Copyright (c) 2006 - 2020, Percona LLC.