Collations Integration Ordering

[king-11]

Description

Engine Update

This PR adds collation support to the engine module specifically focused on making comparer struct collation aware by including collation ID in it which can then be passed down to the NullSafeCompare responsible for actually comparing values.

vitess/go/vt/vtgate/engine/comparer.go

Line 26 in f085f12

type comparer struct {

To be able to pass down collation ID into the comparer struct we need to contain it further up the module level i.e. in OrderByParams.

vitess/go/vt/vtgate/engine/route.go

Line 128 in f085f12

type OrderByParams struct {

Plan Builder Updates

• As the params are populated in planBuilder it becomes trivial to extract collation ID in most cases.

Memory Sort on Aggregation

The plan builder tests were updated so that testing can be done for createMemorySortPlanOnAggregation. For that, the OrderByParams.String() was updated to include the collation name with COLLATE keyword. This changes the description of route for which tests were updated this also allows us to test for createMemorySortPlanOnAggregation using the plan builder tests.

v3

We don't have the semantic table for the v3 planner code and we intend to only add collations support to Gen4 only, after discussing with @systay @frouioui. Hence the TODOs are left in ordering.go and memory_sort.go.

Tests Added

• Route Sort with Collation
• Memory Sort with Collation
• Merge Sort with Collation

Related Issue(s)

• Collation and Character set support #8606

Checklist

• Should this PR be backported?
• Tests were added or are not required
• Documentation was added or is not required

Deployment Notes

[vmg]

The test failures in the unit tests are not flukes. Looks like you need to tweak the code -- a good starting point would be the slice access that is causing a panic.

[king-11]

@vmg the issue is resolved i was trying to access KeyCol instead of actual index