SQL Server Query Slow with Smaller Database - sql

Question

I have 2 tables:
asset - with id_asset, name, ticker (60k rows)
quote_close - with id_asset, refdate, quote_close (22MM rows)
I want to make a filter in name and ticker and return:
id_asset
name
ticker
min(refdate) of the id_asset
max(refdate) of the id_asset
quote_close on max(refdate) of the id_asset
I wrote this query:
WITH tableAssetFiltered AS
(
SELECT
id_asset, ticker, name
FROM
asset
WHERE
ticker LIKE ('%VALE%') AND name LIKE ('%PUT%')
)
SELECT
ast.id_asset, ast.ticker, ast.name,
xx.quote_close as LastQuote, xx.MinDate,
xx.refdate as LastDate
FROM
tableAssetFiltered ast
LEFT JOIN
(SELECT
qc.id_asset, qc.refdate, qc.quote_close, tm.MinDate
FROM
quote_close qc
INNER JOIN
(SELECT
t.id_asset, max(t.refdate) as MaxDate, min(t.refdate) as MinDate
FROM
(SELECT
qc.id_asset, qc.refdate, qc.quote_close
FROM
quote_close qc
WHERE
qc.id_asset IN (SELECT id_asset
FROM tableAssetFiltered)
) t
GROUP BY
t.id_asset) tm ON qc.id_asset = tm.id_asset
AND qc.refdate = tm.MaxDate
) xx ON xx.id_asset = ast.id_asset
ORDER BY
ast.ticker
The results with different filter in name and ticker are:
With ticker like ('%VALE%') AND name like ('%PUT%') it took 00:02:28 and returns 491 rows
With name like ('%PUT%') it took 00:00:02 and returns 16697 rows
With ticker like ('%VALE%') it took 00:00:02 and returns 1102 rows
With no likes it took 00:00:03 and returns 51847 rows
What I can't understand is that the query
SELECT id_asset,ticker, name
FROM Viper.dbo.asset
WHERE ticker like ('%VALE%') AND name like ('%PUT%')
took 00:00:00 to run.
Why does a smaller table took more time to run? Any solution to make it faster?

Answer 1

The slowness could be caused by many things, Hardware, network, caching, etc.
To make the query faster,
1. Make sure that there is an index on ticker.
2. Run update statistics on the table.
3. Try to find a way to remove the '%' at the beginning of the string.
This is okay: 'VALE%'
This will slow down your query: '%VALE'