[Feat] JobPosting 유사도 검색 서비스 추가

ops/db/migrations/20260730_job_posting_embeddings.sql

@@ -0,0 +1,16 @@
+CREATE EXTENSION IF NOT EXISTS vector;
+
+CREATE TABLE IF NOT EXISTS job_posting_embeddings (
+    id BIGSERIAL PRIMARY KEY,
+    job_posting_id BIGINT NOT NULL UNIQUE REFERENCES job_postings(id) ON DELETE CASCADE,
+    embedding_model VARCHAR(100) NOT NULL,
+    embedding vector(1024) NOT NULL,
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE INDEX IF NOT EXISTS idx_job_posting_embeddings_job_posting
+    ON job_posting_embeddings (job_posting_id);
+
+CREATE INDEX IF NOT EXISTS idx_job_posting_embeddings_hnsw
+    ON job_posting_embeddings USING hnsw (embedding vector_cosine_ops);

src/main/java/com/jobdri/jobdri_api/domain/jobposting/dto/response/JobPostingSimilarityResult.java

@@ -0,0 +1,10 @@
+package com.jobdri.jobdri_api.domain.jobposting.dto.response;
+
+public record JobPostingSimilarityResult(
+        Long jobPostingId,
+        String postingName,
+        String companyName,
+        String jobTitle,
+        double similarityScore
+) {
+}

src/main/java/com/jobdri/jobdri_api/domain/jobposting/repository/JobPostingRepository.java

@@ -11,6 +11,8 @@
 import java.util.List;
 
 public interface JobPostingRepository extends JpaRepository<JobPosting, Long> {
+    List<JobPosting> findAllByOrderByIdAsc();
+
     @EntityGraph(attributePaths = {
             "company",
             "user",

src/main/java/com/jobdri/jobdri_api/domain/jobposting/service/JobPostingEmbeddingService.java

@@ -0,0 +1,28 @@
+package com.jobdri.jobdri_api.domain.jobposting.service;
+
+import com.jobdri.jobdri_api.domain.jobposting.entity.JobPosting;
+import com.jobdri.jobdri_api.global.cohere.CohereEmbeddingClient;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+
+@Service
+@RequiredArgsConstructor
+public class JobPostingEmbeddingService {
+
+    private final JobPostingEmbeddingTextBuilder textBuilder;
+    private final CohereEmbeddingClient cohereEmbeddingClient;
+
+    public float[] embed(JobPosting jobPosting) {
+        List<float[]> embeddings = embedAll(List.of(jobPosting));
+        return embeddings.getFirst();
+    }
+
+    public List<float[]> embedAll(List<JobPosting> jobPostings) {
+        List<String> texts = jobPostings.stream()
+                .map(textBuilder::build)
+                .toList();
+        return cohereEmbeddingClient.embedDocuments(texts);
+    }
+}

src/main/java/com/jobdri/jobdri_api/domain/jobposting/service/JobPostingEmbeddingSyncService.java

@@ -0,0 +1,110 @@
+package com.jobdri.jobdri_api.domain.jobposting.service;
+
+import com.jobdri.jobdri_api.domain.jobposting.entity.JobPosting;
+import com.jobdri.jobdri_api.domain.jobposting.repository.JobPostingRepository;
+import com.jobdri.jobdri_api.global.apiPayload.code.GeneralErrorCode;
+import com.jobdri.jobdri_api.global.apiPayload.exception.GeneralException;
+import com.jobdri.jobdri_api.global.cohere.CohereProperties;
+import com.pgvector.PGvector;
+import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.jdbc.datasource.DataSourceUtils;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Timestamp;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+
+@Service
+@RequiredArgsConstructor
+public class JobPostingEmbeddingSyncService {
+
+    private static final String UPSERT_JOB_POSTING_SQL = """
+            INSERT INTO job_posting_embeddings (job_posting_id, embedding_model, embedding, created_at, updated_at)
+            VALUES (?, ?, ?, ?, ?)
+            ON CONFLICT (job_posting_id)
+            DO UPDATE SET
+                embedding_model = EXCLUDED.embedding_model,
+                embedding = EXCLUDED.embedding,
+                updated_at = EXCLUDED.updated_at
+            """;
+
+    @Value("${app.corpus.embedding.batch-size:32}")
+    private int batchSize;
+
+    private final JobPostingRepository jobPostingRepository;
+    private final JobPostingEmbeddingService jobPostingEmbeddingService;
+    private final CohereProperties cohereProperties;
+    private final DataSource dataSource;
+
+    @Transactional
+    public int syncJobPosting(Long jobPostingId) {
+        JobPosting jobPosting = jobPostingRepository.findById(jobPostingId)
+                .orElseThrow(() -> new GeneralException(
+                        GeneralErrorCode.JOB_POSTING_NOT_FOUND,
+                        "해당 공고를 찾을 수 없습니다. jobPostingId=" + jobPostingId
+                ));
+        upsertJobPostingEmbeddings(List.of(jobPosting));
+        return 1;
+    }
+
+    @Transactional
+    public int syncAllJobPostings() {
+        return upsertJobPostingEmbeddings(jobPostingRepository.findAllByOrderByIdAsc());
+    }
+
+    private int upsertJobPostingEmbeddings(List<JobPosting> jobPostings) {
+        int processed = 0;
+        for (List<JobPosting> batch : partition(jobPostings, batchSize)) {
+            List<float[]> embeddings = jobPostingEmbeddingService.embedAll(batch);
+            upsertVectors(batch.stream().map(JobPosting::getId).toList(), embeddings);
+            processed += batch.size();
+        }
+        return processed;
+    }
+
+    private void upsertVectors(List<Long> jobPostingIds, List<float[]> embeddings) {
+        if (jobPostingIds.size() != embeddings.size()) {
+            throw new IllegalStateException("임베딩 결과 개수가 채용 공고 개수와 일치하지 않습니다.");
+        }
+
+        Connection connection = DataSourceUtils.getConnection(dataSource);
+        try {
+            PGvector.registerTypes(connection);
+            try (PreparedStatement statement = connection.prepareStatement(UPSERT_JOB_POSTING_SQL)) {
+                Timestamp now = Timestamp.valueOf(LocalDateTime.now());
+                for (int i = 0; i < jobPostingIds.size(); i++) {
+                    statement.setLong(1, jobPostingIds.get(i));
+                    statement.setString(2, cohereProperties.embedding().model());
+                    statement.setObject(3, new PGvector(embeddings.get(i)));
+                    statement.setTimestamp(4, now);
+                    statement.setTimestamp(5, now);
+                    statement.addBatch();
+                }
+                statement.executeBatch();
+            }
+        } catch (SQLException e) {
+            throw new IllegalStateException("채용 공고 임베딩 벡터 저장 중 오류가 발생했습니다.", e);
+        } finally {
+            DataSourceUtils.releaseConnection(connection, dataSource);
+        }
+    }
+
+    private <T> List<List<T>> partition(List<T> items, int batchSize) {
+        List<List<T>> result = new ArrayList<>();
+        if (items.isEmpty()) {
+            return result;
+        }
+        int actualBatchSize = Math.max(1, batchSize);
+        for (int i = 0; i < items.size(); i += actualBatchSize) {
+            result.add(items.subList(i, Math.min(items.size(), i + actualBatchSize)));
+        }
+        return result;
+    }
+}

src/main/java/com/jobdri/jobdri_api/domain/jobposting/service/JobPostingEmbeddingTextBuilder.java

@@ -0,0 +1,28 @@
+package com.jobdri.jobdri_api.domain.jobposting.service;
+
+import com.jobdri.jobdri_api.domain.jobposting.entity.JobPosting;
+import org.springframework.stereotype.Component;
+import org.springframework.util.StringUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Component
+public class JobPostingEmbeddingTextBuilder {
+
+    public String build(JobPosting jobPosting) {
+        List<String> sections = new ArrayList<>();
+        addSection(sections, "직무", jobPosting.getJobTitle());
+        addSection(sections, "주요업무", jobPosting.getTask());
+        addSection(sections, "자격요건", jobPosting.getRequirement());
+        addSection(sections, "우대사항", jobPosting.getPreferred());
+        return String.join("\n\n", sections);
+    }
+
+    private void addSection(List<String> sections, String title, String value) {
+        if (!StringUtils.hasText(value)) {
+            return;
+        }
+        sections.add(title + "\n" + value.trim());
+    }
+}

src/main/java/com/jobdri/jobdri_api/domain/jobposting/service/JobPostingRetrievalService.java

@@ -0,0 +1,97 @@
+package com.jobdri.jobdri_api.domain.jobposting.service;
+
+import com.jobdri.jobdri_api.domain.jobposting.dto.response.JobPostingSimilarityResult;
+import com.jobdri.jobdri_api.domain.jobposting.entity.JobPosting;
+import com.jobdri.jobdri_api.domain.jobposting.repository.JobPostingRepository;
+import com.jobdri.jobdri_api.global.apiPayload.code.GeneralErrorCode;
+import com.jobdri.jobdri_api.global.apiPayload.exception.GeneralException;
+import com.jobdri.jobdri_api.global.cohere.CohereEmbeddingClient;
+import com.pgvector.PGvector;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.List;
+
+@Service
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+public class JobPostingRetrievalService {
+
+    private static final int DEFAULT_LIMIT = 3;
+    private static final String SIMILAR_JOB_POSTINGS_SQL = """
+            SELECT
+                jp.id,
+                jp.posting_name,
+                c.name AS company_name,
+                jp.job_title,
+                e.embedding <=> ? AS distance
+            FROM job_posting_embeddings e
+            JOIN job_postings jp ON e.job_posting_id = jp.id
+            JOIN companies c ON jp.company_id = c.id
+            WHERE jp.id <> ?
+              AND jp.user_id = ?
+            ORDER BY e.embedding <=> ?
+            LIMIT ?
+            """;
+
+    private final JobPostingRepository jobPostingRepository;
+    private final JobPostingEmbeddingTextBuilder textBuilder;
+    private final CohereEmbeddingClient cohereEmbeddingClient;
+    private final DataSource dataSource;
+
+    public List<JobPostingSimilarityResult> findSimilarJobPostings(Long jobPostingId) {
+        return findSimilarJobPostings(jobPostingId, DEFAULT_LIMIT);
+    }
+
+    public List<JobPostingSimilarityResult> findSimilarJobPostings(Long jobPostingId, int limit) {
+        JobPosting current = jobPostingRepository.findById(jobPostingId)
+                .orElseThrow(() -> new GeneralException(
+                        GeneralErrorCode.JOB_POSTING_NOT_FOUND,
+                        "해당 공고를 찾을 수 없습니다. jobPostingId=" + jobPostingId
+                ));
+        int actualLimit = Math.max(1, limit);
+        String query = textBuilder.build(current);
+        float[] vector = cohereEmbeddingClient.embedQuery(query);
+        return findSimilarJobPostings(current, vector, actualLimit);
+    }
+
+    private List<JobPostingSimilarityResult> findSimilarJobPostings(
+            JobPosting current,
+            float[] vector,
+            int limit
+    ) {
+        try (Connection connection = dataSource.getConnection()) {
+            PGvector.registerTypes(connection);
+            try (PreparedStatement statement = connection.prepareStatement(SIMILAR_JOB_POSTINGS_SQL)) {
+                statement.setObject(1, new PGvector(vector));
+                statement.setLong(2, current.getId());
+                statement.setLong(3, current.getUser().getId());
+                statement.setObject(4, new PGvector(vector));
+                statement.setInt(5, limit);
+                try (ResultSet resultSet = statement.executeQuery()) {
+                    List<JobPostingSimilarityResult> results = new ArrayList<>();
+                    while (resultSet.next()) {
+                        double distance = resultSet.getDouble("distance");
+                        results.add(new JobPostingSimilarityResult(
+                                resultSet.getLong("id"),
+                                resultSet.getString("posting_name"),
+                                resultSet.getString("company_name"),
+                                resultSet.getString("job_title"),
+                                1.0 - distance
+                        ));
+                    }
+                    return results;
+                }
+            }
+        } catch (SQLException e) {
+            throw new IllegalStateException("유사 채용 공고 검색 중 오류가 발생했습니다.", e);
+        }
+    }
+}

src/main/resources/schema.sql

@@ -19,6 +19,15 @@ CREATE TABLE IF NOT EXISTS mock_question_embeddings (
     updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
+CREATE TABLE IF NOT EXISTS job_posting_embeddings (
+    id BIGSERIAL PRIMARY KEY,
+    job_posting_id BIGINT NOT NULL UNIQUE REFERENCES job_postings(id) ON DELETE CASCADE,
+    embedding_model VARCHAR(100) NOT NULL,
+    embedding vector(1024) NOT NULL,
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
 CREATE INDEX IF NOT EXISTS idx_job_postings_company_detail
     ON job_postings (company_id, detail_classification_id);
 
@@ -34,12 +43,18 @@ CREATE INDEX IF NOT EXISTS idx_mock_job_posting_embeddings_corpus
 CREATE INDEX IF NOT EXISTS idx_mock_question_embeddings_corpus
     ON mock_question_embeddings (corpus_id);
 
+CREATE INDEX IF NOT EXISTS idx_job_posting_embeddings_job_posting
+    ON job_posting_embeddings (job_posting_id);
+
 CREATE INDEX IF NOT EXISTS idx_mock_job_posting_embeddings_hnsw
     ON mock_job_posting_embeddings USING hnsw (embedding vector_cosine_ops);
 
 CREATE INDEX IF NOT EXISTS idx_mock_question_embeddings_hnsw
     ON mock_question_embeddings USING hnsw (embedding vector_cosine_ops);
 
+CREATE INDEX IF NOT EXISTS idx_job_posting_embeddings_hnsw
+    ON job_posting_embeddings USING hnsw (embedding vector_cosine_ops);
+
 ALTER TABLE IF EXISTS analyses
     ADD COLUMN IF NOT EXISTS missing_keywords TEXT NOT NULL DEFAULT '[]';