sql: populate indexprs column of pg_catalog.pg_index

[mgartner]

sql: populate indexprs column of pg_catalog.pg_index

This commit also fixes the formatting of user-defined types in the
indexdef column of pg_catalog.pg_indexes and the indpred column of
pg_catalog.pg_index.

Release note (bug fix): The indexprs column of pg_catalog.pg_index
is now populated with string representations of every expression element
in the index. If the index is not an expression index, indexprs is
NULL. The indexdef column of pg_catalog.pg_indexes and the
indpred column of pg_catalog.pg_index now correctly display
user-defined types.

[cockroach-teamcity]

This change is 

[rafiss]

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

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pkg/sql/pg_catalog.go, line 1710 at r1 (raw file):

						if col.IsExpressionIndexColumn() {
							colIDs = append(colIDs, 0)
							exprs = append(exprs, fmt.Sprintf("(%s)", col.GetComputeExpr()))

we potentially might want to be using schemaexpr.FormatExprForDisplay() -- take a look at the other usages in this file. I forget the exact reasoning, but I believe you worked on that function before, so hopefully together we can remember :)

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pkg/sql/pg_catalog.go, line 1750 at r1 (raw file):

					indpred := tree.DNull
					if index.IsPartial() {
						indpred = tree.NewDString(index.GetPredicate())

maybe schemaexpr.FormatExprForDisplay() here too?

[mgartner]

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

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pkg/sql/pg_catalog.go, line 1710 at r1 (raw file):

Previously, rafiss (Rafi Shamim) wrote…

we potentially might want to be using schemaexpr.FormatExprForDisplay() -- take a look at the other usages in this file. I forget the exact reasoning, but I believe you worked on that function before, so hopefully together we can remember :)

Good point. We need to use this to correct print user-defined types. I've added some tests cases to highlight this.

This also led me to stumble upon this bug, which I won't try to fix in this PR, if that's ok with you: #72241

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pkg/sql/pg_catalog.go, line 1750 at r1 (raw file):

Previously, rafiss (Rafi Shamim) wrote…

maybe schemaexpr.FormatExprForDisplay() here too?

Done.

[rafiss]

lgtm! and thanks for uncovering that other issue

Reviewed 2 of 2 files at r2, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @rafiss)

[mgartner]

TFTR!

bors r+

[craig]

Build succeeded:

• GitHub CI (Cockroach)

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error creating merge commit from 072cb20 to blathers/backport-release-21.2-72238: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 21.2.x failed. See errors above.

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