# slow text search query

A slow query turned out to do a join on latin1 and utf8 columns. That was
very slow!

The query contains

```
WHERE (((Phenotype.Post_publication_description
LIKE "%liver%" OR Phenotype.Pre_publication_description LIKE "%liver%" OR
Phenotype.Pre_publication_abbreviation LIKE "%liver%" OR
Phenotype.Post_publication_abbreviation LIKE "%liver%" OR
Phenotype.Lab_code LIKE "%liver%" OR Publication.PubMed_ID LIKE "%liver%"
OR Publication.Abstract LIKE "%liver%" OR Publication.Title LIKE "%liver%"
OR Publication.Authors LIKE "%liver%" OR PublishXRef.Id LIKE "%liver%") ))
```

Below page describes the issue. Essentially an index won't help and
mariadb will scan the whole file for every query. Not good.

=> https://stackoverflow.com/questions/2042269/how-to-speed-up-select-like-queries-in-mysql-on-multiple-columns

This is a typical candidate for FULLTEXT searches where we do a multi
match against the larger fields, e.g.

    Add a full text index on the columns that you need:

        ALTER TABLE table ADD FULLTEXT INDEX index_table_on_x_y_z (x, y, z);

    Then query those columns:

        SELECT * FROM table WHERE MATCH(x,y,z) AGAINST("text")

I think we can try creating a fulltext for index for Abstract, Title
and Authors - since these are longer strings.

Again, I note we are doing this the wrong way. We'll unify xapian -
have you seen how fast that is? But Arun and I need more time to get
the menu search in place.

So, let's try some things.

```
ALTER TABLE Publication ADD FULLTEXT INDEX index_table (Title, Abstract, Authors);
SELECT * FROM Publication WHERE MATCH(Title, Abstract, Authors) AGAINST("diabetes");
```

renders 23 rows in 0.001 seconds. The combined is still slow, so let's check the Phenotype table too. It has

```
Phenotype.Post_publication_description
Phenotype.Pre_publication_description
Phenotype.Pre_publication_abbreviation
Phenotype.Post_publication_abbreviation
Phenotype.Lab_code
Publication.PubMed_ID
```

not sure why we need most of these, but let's create an index

```
ALTER TABLE Phenotype ADD FULLTEXT INDEX index_table (Post_publication_description,Pre_publication_description,Pre_publication_abbreviation,Post_publication_abbreviation,Lab_code);
SELECT * FROM Phenotype WHERE MATCH(Post_publication_description,Pre_publication_description,Pre_publication_abbreviation,Post_publication_abbreviation,Lab_code) AGAINST("liver");
```

and that is fast too. Let's combine these. Still slow (darn!). So it must be on the joins.

```
                INNER JOIN InbredSet ON InbredSet.'SpeciesId' =
 Species.'Id'
                 INNER JOIN PublishXRef ON PublishXRef.'InbredSetId' =
 InbredSet.'Id'
                 INNER JOIN PublishFreeze ON PublishFreeze.'InbredSetId' =
 InbredSet.'Id'
                 INNER JOIN Publication ON Publication.'Id' =
 PublishXRef.'PublicationId'
                 INNER JOIN Phenotype ON Phenotype.'Id' =
 PublishXRef.'PhenotypeId'
                 LEFT JOIN Geno ON PublishXRef.Locus = Geno.Name AND
 Geno.SpeciesId = Species.Id
```

when I remove the final left join the query is fast. That means we can focus on Geno and PublishXRef tables.

First for some reason Geno was still latin1:

```
ALTER TABLE Geno CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;
```

After that the search is fast.

A nice search now:

```
SELECT PublishXRef.Id,
                 CAST(Phenotype.'Pre_publication_description' AS BINARY),
                 CAST(Phenotype.'Post_publication_description' AS BINARY),
                 Publication.'Authors',
                 Publication.'Year',
                 Publication.'PubMed_ID',
                 PublishXRef.'mean',
                 PublishXRef.'LRS',
                 PublishXRef.'additive',
                 PublishXRef.'Locus',
                 InbredSet.'InbredSetCode',
                 Geno.'Chr',
                 Geno.'Mb'
                 FROM Species
                 INNER JOIN InbredSet ON InbredSet.'SpeciesId' =
 Species.'Id'
                 INNER JOIN PublishXRef ON PublishXRef.'InbredSetId' =
 InbredSet.'Id'
                 INNER JOIN PublishFreeze ON PublishFreeze.'InbredSetId' =
 InbredSet.'Id'
                 INNER JOIN Publication ON Publication.'Id' =
 PublishXRef.'PublicationId'
                 INNER JOIN Phenotype ON Phenotype.'Id' =
 PublishXRef.'PhenotypeId'
                 LEFT JOIN Geno ON PublishXRef.Locus = Geno.Name AND
 Geno.SpeciesId = Species.Id
                         WHERE (((
 MATCH(Post_publication_description,Pre_publication_description,Pre_publication_abbreviation,Post_publication_abbreviat
ion,Lab_code) AGAINST("liver")
 OR Publication.PubMed_ID LIKE "%liver%"
 OR MATCH(Title, Abstract, Authors) AGAINST("liver")
 OR PublishXRef.Id LIKE "%liver%") ))
                         and PublishXRef.InbredSetId = 1
                         and PublishXRef.PhenotypeId = Phenotype.Id
                         and PublishXRef.PublicationId = Publication.Id
                         and PublishFreeze.Id = 1
                         ORDER BY PublishXRef.Id
```