Fix QueryCanceled error in PersistSecurityPoliciesWorker

What does this MR do and why?

This MR replaces each_batch for getting all projects in a namespace with Gitlab::Database::NamespaceEachBatch as it timesout for namespaces with a large number of projects.

Database queries

Before

SELECT
    "projects"."id" 
FROM
    "projects" 
WHERE
    "projects"."namespace_id" IN (
        SELECT
            namespaces.traversal_ids[array_length(namespaces.traversal_ids,
            1)] AS id 
        FROM
            "namespaces" 
        WHERE
            "namespaces"."type" = 'Group' 
            AND (
                traversal_ids @> (
                    '{4249178}'
                )
            )
    ) 
    AND "projects"."id" >= 22187539 
ORDER BY
    "projects"."id" ASC LIMIT 1 OFFSET 1000;

SELECT
    "projects"."id" 
FROM
    "projects" 
WHERE
    "projects"."namespace_id" IN (
        SELECT
            namespaces.traversal_ids[array_length(namespaces.traversal_ids,
            1)] AS id 
        FROM
            "namespaces" 
        WHERE
            "namespaces"."type" = 'Group' 
            AND (
                traversal_ids @> (
                    '{4249178}'
                )
            )
    ) 
    AND "projects"."id" >= 22187539 
    AND "projects"."id" < 22981486;

Query Plan 1 Query Plan 1

After

SELECT
    "projects"."id" 
FROM
    "projects" 
WHERE
    "projects"."namespace_id" IN (
        SELECT
            namespaces.traversal_ids[array_length(namespaces.traversal_ids,
            1)] AS id 
        FROM
            "namespaces" 
        WHERE
            "namespaces"."type" = 'Group' 
            AND (
                traversal_ids @> (
                    '{4249178}'
                )
            )
    ) 
    AND "projects"."id" > 22187539
ORDER BY
    "projects"."id" ASC LIMIT 1000;

Query Plan

References

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• Kibana failure logs
• Issue

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Before	After

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