Use parameter equality when only single value for V3 node

[n-h-diaz]

For parameterized queries, "IN UNNEST()" and "=" are treated differently even for just a single parameter value

Based on analysis with Spanner team, explicitly using "=" when there is a single parameter value has significant latency improvements, as Spanner can make a more optimized query plan, so this PR switches query templates to use equality whenever possible

As a side effect of the new query plans (based on some testing) it now seems better to add filters after the main statement, so this PR also reverses the order of subqueries

I did some testing of some logged production slow Spanner queries,

• nodes=wikidataId/Q1312844&property=<-containedInPlace+{typeOf:Village} [autopush: 7.41s, local: 2.51s]
• nodes=wikidataId/Q2222026&property=<-containedInPlace+{typeOf:AdministrativeArea4} [autopush: 12.07s, local: 2.69s]
• nodes=wikidataId/Q1797336&property=<-containedInPlace+{typeOf:Place} [autopush: 28.96s, local: 3.22s]

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request focuses on improving the performance of Spanner queries by modifying query templates to use equality checks (=) when dealing with single parameter values. This change allows Spanner to generate more optimized query plans, resulting in reduced latency. Additionally, the PR reorders subqueries to add filters after the main statement, further enhancing query performance based on testing results.

Highlights

• Performance Optimization: This PR optimizes Spanner queries by using equality checks (=) instead of IN UNNEST() for single parameter values, leading to significant latency improvements.
• Query Plan Improvement: The changes in query plans now favor adding filters after the main statement, which has shown better performance in testing.
• Template Modification: Modified query templates to use equality checks when possible, enhancing Spanner's ability to create optimized query plans.

Changelog

• internal/server/spanner/golden/query_builder/get_node_edges_first_page.sql
  • Replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_first_page_chain.sql
  • Replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_in_bracket_props.sql
  • Replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_in_chain.sql
  • Replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_in_filter.sql
  • Reordered subqueries and replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_in_single_prop.sql
  • Replaced IN with = for m.subject_id and e.predicate.
• internal/server/spanner/golden/query_builder/get_node_edges_linked_contained_in_place.sql
  • Reordered subqueries and replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_malicious.sql
  • Reordered subqueries and replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_out_bracket_props.sql
  • Replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_out_chain.sql
  • Replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_out_filter.sql
  • Reordered subqueries and replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_out_single_prop.sql
  • Replaced IN with = for m.subject_id and e.predicate.
• internal/server/spanner/golden/query_builder/get_node_edges_second_page.sql
  • Replaced IN with = for m.subject_id.
• internal/server/spanner/golden/query_builder/get_node_edges_second_page_chain.sql
  • Replaced IN with = for m.subject_id.
• internal/server/spanner/query_builder.go
  • Modified GetNodePropsQuery to use equality checks for single IDs.
  • Modified GetNodeEdgesByIDQuery to use equality checks for single IDs and reordered subqueries.
• internal/server/spanner/statements.go
  • Added getId and getIds to statements.
  • Updated getPropsBySubjectID and getPropsByObjectID to use the new id formats.
  • Updated getEdgesBySubjectID, getChainedEdgesBySubjectID, getEdgesByObjectID, and getChainedEdgesByObjectID to use the new id formats.
  • Updated filterPredicate and added filterPredicates.
  • Updated filterProperty and added filterValue and filterValues.

Activity

• The PR author, n-h-diaz, has addressed performance concerns by switching from IN UNNEST() to = for single parameter values in Spanner queries.
• Testing was conducted on logged production slow Spanner queries, showing significant latency improvements.

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[gemini-code-assist]

Code Review

This pull request aims to improve Spanner query latency by replacing IN UNNEST() with = for single-value parameters and reordering subqueries. While a security audit found no vulnerabilities, particularly concerning SQL injection with fmt.Sprintf due to proper parameterization, a flaw was identified in the handling of filter values. Specifically, addObjectValues is called unconditionally, which results in incorrect queries for DCID-based properties like typeOf and prevents the intended performance optimization. A specific code suggestion has been provided to resolve this.

[keyurva]

Thanks Natalie - amazing latency improvements!