explain Questions
6
Solved
The MySQL 5.7 documentation states:
The filtered column indicates an estimated percentage of table rows that will be filtered by the table condition. That is, rows shows the estimated number of ...
Towny asked 8/1, 2017 at 16:16
3
Solved
I need to know how long a particular query will run (I'm expecting a very long run time). To do this, I've decided to run an EXPLAIN ANALYZE on the query set with only a piece of the entire dataset...
Subadar asked 11/4, 2016 at 20:18
3
Solved
What does Using join buffer (Block Nested Loop) mean with EXPLAIN mysql command in the Extra column?
I am trying to optimize my query.
And getting Using join buffer (Block Nested Loop)
for one of the table with
EXPLAIN SELECT command.
I have no idea what does it mean.
I tried googling about, but I...
1
Solved
I'm trying to alter the type of a column from a table but I also want to know how long it takes to alter the table. I therefore combined:
EXPLAIN ANALYSE
command with:
ALTER TABLE tbl_name ALTER C...
Lattice asked 23/3, 2022 at 18:33
4
Solved
I'm new to query optimizations so I accept I don't understand everything yet but I do not understand why even this simple query isn't optimized as expected.
My table:
+------------------+--------...
2
Solved
I know I could get the raw query from the query log, paste in all the bound variables (also found in the query log), slap a explain at the front of the query, and run it directly in the mysql conso...
4
Solved
mysql> select count(*) from table where relation_title='xxxxxxxxx';
+----------+
| count(*) |
+----------+
| 1291958 |
+----------+
mysql> explain select * from table where relation_title='...
1
Solved
I want to know what does Using filesort mean in MySQL?
explain select * from user order by user_id;
It turn up when i use 'order by'.
1,SIMPLE,orderitems,,ALL,,,,,1,100,Using filesort
The 'Using ...
Pronuba asked 27/1, 2021 at 3:8
2
I have a sql like:
DBSession().query(Model).filter(***)
and I want to explain this sql using SQLAlchemy.
Colecolectomy asked 23/6, 2013 at 14:10
1
Solved
According to the MySQL documentation, Using where means: A WHERE clause is used to restrict which rows to match against the next table or send to the client.
As I understand, it means if your sql s...
Selfpollination asked 17/7, 2020 at 5:6
2
mysql> CREATE TABLE `t` (
`id` int(11) NOT NULL,
`a` int(11) DEFAULT NULL,
`b` int(11) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `a` (`a`),
KEY `b` (`b`)
) ENGINE=InnoDB
there is a table na...
1
Is there any proper resource from where we can understand explain plan generated by hive completely? I have tried searching it in the wiki but could not find a complete guide to understand it.
Here...
Aneroidograph asked 11/6, 2018 at 7:58
1
Solved
In Postgres, some queries are a whole lot slower when adding a LIMIT:
The queries:
SELECT * FROM review WHERE clicker_id=28 ORDER BY done DESC LIMIT 4; -- 51 sec
SELECT * FROM review WHERE clicke...
Second asked 7/2, 2020 at 14:30
1
Solved
I just got the next result of MySQL Explain closure:
And I, unfortunately, don't understand what does it mean MATERIALIZED in the last row of the select_type column.
If somebody knows what does...
1
Solved
I'm using a database client to test.
Using EXPLAIN ANALYZE:
Hash Join (cost=5.02..287015.54 rows=3400485 width=33) (actual time=0.023..1725.842 rows=3327845 loops=1)
Hash Cond: ((fact_orders.fi...
Dayna asked 12/11, 2019 at 22:44
1
Solved
I have 2 tables, "transaksi" and "buku". "transaksi" has around ~250k rows, and buku has around ~170k rows. Both tables have column called "k999a", and both tables use no indexes. Now I check these...
Sanguinary asked 4/10, 2018 at 3:30
2
Here's an example plan on explain.depesz.com:
Limit (cost=65301.950..65301.950 rows=1 width=219) (actual time=886.074..886.074 rows=0 loops=1)
-> Sort (cost=65258.840..65301.950 rows=17243 wid...
Josie asked 15/2, 2014 at 3:10
2
Solved
Im wondering how I can fetch the explain plan using Java. Reason I need this is because we have a framework where special users can craft reports. These reports sometimes build huge queries in whic...
Libertinism asked 7/12, 2010 at 11:59
1
Solved
I am profiling my query.
postgres=# explain analyze select * from student;
QUERY PLAN
------------------------------------------------------------------------------------------------------
Seq S...
Shrovetide asked 9/4, 2018 at 13:3
2
I get a "Range checked for each record (index map: 0x1)" in EXPLAIN SELECT when doing an INNER JOIN on a PRIMARY key with 2 values (using either IN or OR constructs)
Here is the query:
SELECT *
F...
3
Solved
I'm planning on creating a view using this SQL SELECT, but the explain for it shows it's using temporary and using filesort. I can't figure out what indices I need in order to fix this problem.
Mos...
1
Solved
I succesfully run:
result = my_col.aggregate(my_pipeline, allowDiskUse=True)
Now when I try:
result = my_col.aggregate(my_pipeline, allowDiskUse=True, explain=True)
it fails saying:
pymongo....
Ping asked 28/4, 2017 at 9:47
1
I have a following table
CREATE TABLE `test_series_analysis_data` (
`email` varchar(255) NOT NULL,
`mappingId` int(11) NOT NULL,
`packageId` varchar(255) NOT NULL,
`sectionName` varchar(255) N...
Densify asked 12/1, 2017 at 18:22
1
Below is the update query/query plan that is not using the compound index that was created recently. The explain shows that its not using the compound index named radacctupdate which i think will m...
Cain asked 8/1, 2017 at 6:36
1
I am trying to interpret the explain of mysql in a query(written in two different ways),this is the table:
create table text_mess(
datamess timestamp(3) DEFAULT 0,
sender bigint ,
recipient bi...
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