sql: improved diff tool for any namespace

[mnovelodou]

Previously, diff tool worked only for pg_catalog
This was inadequate because it can be used for information_schema as well
To address this, this patch takes the namespace as parameter to compare a
different database

Release note: None
Release justification: non-production code changes

Fixes #58037

[blathers-crl]

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[cockroach-teamcity]

This change is 

[RichardJCai]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @mnovelodou and @rafiss)

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pkg/sql/pg_catalog_test.go, line 49 at r1 (raw file):

// Test data files
const (
	pgCatalogDump = "%s_tables.json"              // PostgreSQL pg_catalog schema

Doesn't make sense to call this pgCatalogDump anymore, same with the comments below.

---

pkg/sql/pg_catalog_test.go, line 85 at r1 (raw file):

func loadTestData(t testing.TB) PGCatalogTables {
	var pgCatalogFile PGCatalogFile
	testdataFile := filepath.Join(testdata, fmt.Sprintf(pgCatalogDump, *postgresCatalog))

I think we should figure out how to parameterize *postgresCatalog here and the other instances where we use it for formatting since right now it's all hardcoded in a global variable.

[blathers-crl]

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My owl senses detect your PR is good for review. Please keep an eye out for any test failures in CI.

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[mnovelodou]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @rafiss and @RichardJCai)

---

pkg/sql/pg_catalog_test.go, line 49 at r1 (raw file):

Previously, RichardJCai (Richard Cai) wrote…

Doesn't make sense to call this pgCatalogDump anymore, same with the comments below.

Done.

---

pkg/sql/pg_catalog_test.go, line 85 at r1 (raw file):

Previously, RichardJCai (Richard Cai) wrote…

I think we should figure out how to parameterize *postgresCatalog here and the other instances where we use it for formatting since right now it's all hardcoded in a global variable.

It is done as the value comes from flag

[RichardJCai]

Looks good to me except for the folder name / some var names.

Need approval from @rafiss as well.

[rafiss]

sorry! i just noticed some more names that should be renamed now.

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @mnovelodou and @RichardJCai)

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pkg/sql/pg_catalog_diff.go, line 1 at r3 (raw file):

// Copyright 2020 The Cockroach Authors.

nit: rename the file to pg_metadata_diff.go

---

pkg/sql/pg_catalog_diff.go, line 24 at r3 (raw file):

// GetPGCatalogSQL is a query uses udt_name::regtype instead of data_type column because
// data_type only says "ARRAY" but does not say which kind of array it is.
const GetPGCatalogSQL = `

nit: rename to GetPGMetadataSQL

---

pkg/sql/pg_catalog_diff.go, line 41 at r3 (raw file):

// PGCatalogColumn is a structure which contains a small description about the datatype of a column, but this can also be
// used as a diff information if populating ExpectedOid. Fields are exported for Marshaling purposes.
type PGCatalogColumn struct {

nit: rename to PGMetadataColumn

---

pkg/sql/pg_catalog_diff.go, line 49 at r3 (raw file):

// PGCatalogColumns maps column names to datatype description
type PGCatalogColumns map[string]*PGCatalogColumn

nit: rename to PGMetadataColumns

---

pkg/sql/pg_catalog_diff.go, line 61 at r3 (raw file):

// - If column Name points to a not null PGCatalogColumn, the test column describes how we expect that data type to be
//   different between cockroach db and postgres
type PGCatalogTables map[string]PGCatalogColumns

nit: rename to PGMetadataTables

---

pkg/sql/pg_catalog_diff.go, line 65 at r3 (raw file):

// PGCatalogFile is used to export pg_catalog from postgres and store the representation of this structure as a
// json file
type PGCatalogFile struct {

nit: rename to PGMetadataFile

---

pkg/sql/pg_catalog_diff.go, line 67 at r3 (raw file):

type PGCatalogFile struct {
	PgVersion string          `json:"pgVersion"`
	PgCatalog PGCatalogTables `json:"pgCatalog"`

nit: rename the variable to PgMetadata

also, not sure but should it be PGMetadata to match the capitalisation of the other names?

[mnovelodou]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @mnovelodou, @rafiss, and @RichardJCai)

---

pkg/sql/pg_catalog_diff.go, line 41 at r3 (raw file):

Previously, rafiss (Rafi Shamim) wrote…

nit: rename to PGMetadataColumn

Renamed PGMetadataColumnType as this structure contains information more related to the type

[rafiss]

looks great! thanks

bors r+

Reviewed 1 of 5 files at r1, 1 of 3 files at r3, 6 of 6 files at r4.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @rafiss and @RichardJCai)

[craig]

Build failed (retrying...):

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[craig]

This PR was included in a batch that was canceled, it will be automatically retried

[craig]

Build succeeded:

• GitHub CI (Cockroach)