diff --git a/db/migrations/0031_phase2_observability_and_pooling.sql b/db/migrations/0031_phase2_observability_and_pooling.sql
index add042c1..11568f84 100644
--- a/db/migrations/0031_phase2_observability_and_pooling.sql
+++ b/db/migrations/0031_phase2_observability_and_pooling.sql
@@ -20,9 +20,9 @@ CREATE TABLE IF NOT EXISTS opendata.opendart_cache (
     UNIQUE(ticker, quarter)
 );
 
-CREATE INDEX idx_opendart_cache_ticker ON opendata.opendart_cache(ticker);
-CREATE INDEX idx_opendart_cache_expires_at ON opendata.opendart_cache(expires_at);
-CREATE INDEX idx_opendart_cache_published_at ON opendata.opendart_cache(published_at);
+CREATE INDEX IF NOT EXISTS idx_opendart_cache_ticker ON opendata.opendart_cache(ticker);
+CREATE INDEX IF NOT EXISTS idx_opendart_cache_expires_at ON opendata.opendart_cache(expires_at);
+CREATE INDEX IF NOT EXISTS idx_opendart_cache_published_at ON opendata.opendart_cache(published_at);
 
 -- OpenDart batch execution log
 CREATE TABLE IF NOT EXISTS opendata.opendart_batch_log (
@@ -38,8 +38,8 @@ CREATE TABLE IF NOT EXISTS opendata.opendart_batch_log (
     UNIQUE(batch_date)
 );
 
-CREATE INDEX idx_opendart_batch_log_batch_date ON opendata.opendart_batch_log(batch_date);
-CREATE INDEX idx_opendart_batch_log_status ON opendata.opendart_batch_log(status);
+CREATE INDEX IF NOT EXISTS idx_opendart_batch_log_batch_date ON opendata.opendart_batch_log(batch_date);
+CREATE INDEX IF NOT EXISTS idx_opendart_batch_log_status ON opendata.opendart_batch_log(status);
 
 -- ============================================================================
 -- KIS SCHEMA: Korea Investment & Securities Connection Pool
@@ -62,9 +62,9 @@ CREATE TABLE IF NOT EXISTS kis.connection_pool_state (
     UNIQUE(connection_id)
 );
 
-CREATE INDEX idx_kis_connection_pool_state ON kis.connection_pool_state(state);
-CREATE INDEX idx_kis_connection_pool_expires_at ON kis.connection_pool_state(expires_at);
-CREATE INDEX idx_kis_connection_pool_priority ON kis.connection_pool_state(priority);
+CREATE INDEX IF NOT EXISTS idx_kis_connection_pool_state ON kis.connection_pool_state(state);
+CREATE INDEX IF NOT EXISTS idx_kis_connection_pool_expires_at ON kis.connection_pool_state(expires_at);
+CREATE INDEX IF NOT EXISTS idx_kis_connection_pool_priority ON kis.connection_pool_state(priority);
 
 -- KIS token refresh log
 CREATE TABLE IF NOT EXISTS kis.token_refresh_log (
@@ -78,9 +78,9 @@ CREATE TABLE IF NOT EXISTS kis.token_refresh_log (
     published_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
-CREATE INDEX idx_kis_token_refresh_connection_id ON kis.token_refresh_log(connection_id);
-CREATE INDEX idx_kis_token_refresh_status ON kis.token_refresh_log(status);
-CREATE INDEX idx_kis_token_refresh_executed_at ON kis.token_refresh_log(executed_at);
+CREATE INDEX IF NOT EXISTS idx_kis_token_refresh_connection_id ON kis.token_refresh_log(connection_id);
+CREATE INDEX IF NOT EXISTS idx_kis_token_refresh_status ON kis.token_refresh_log(status);
+CREATE INDEX IF NOT EXISTS idx_kis_token_refresh_executed_at ON kis.token_refresh_log(executed_at);
 
 -- ============================================================================
 -- INFRASTRUCTURE SCHEMA: Rate Limiting & Circuit Breaker
@@ -102,7 +102,7 @@ CREATE TABLE IF NOT EXISTS infrastructure.rate_limit_quota (
     UNIQUE(api_name)
 );
 
-CREATE INDEX idx_rate_limit_quota_api_name ON infrastructure.rate_limit_quota(api_name);
+CREATE INDEX IF NOT EXISTS idx_rate_limit_quota_api_name ON infrastructure.rate_limit_quota(api_name);
 
 -- Rate limit events (for audit trail)
 CREATE TABLE IF NOT EXISTS infrastructure.rate_limit_events (
@@ -117,8 +117,8 @@ CREATE TABLE IF NOT EXISTS infrastructure.rate_limit_events (
     published_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
-CREATE INDEX idx_rate_limit_events_api_name ON infrastructure.rate_limit_events(api_name);
-CREATE INDEX idx_rate_limit_events_occurred_at ON infrastructure.rate_limit_events(occurred_at);
+CREATE INDEX IF NOT EXISTS idx_rate_limit_events_api_name ON infrastructure.rate_limit_events(api_name);
+CREATE INDEX IF NOT EXISTS idx_rate_limit_events_occurred_at ON infrastructure.rate_limit_events(occurred_at);
 
 -- Circuit breaker state
 CREATE TABLE IF NOT EXISTS infrastructure.circuit_breaker_state (
@@ -135,7 +135,7 @@ CREATE TABLE IF NOT EXISTS infrastructure.circuit_breaker_state (
     UNIQUE(api_name)
 );
 
-CREATE INDEX idx_circuit_breaker_state_api_name ON infrastructure.circuit_breaker_state(api_name);
+CREATE INDEX IF NOT EXISTS idx_circuit_breaker_state_api_name ON infrastructure.circuit_breaker_state(api_name);
 
 -- Circuit breaker events (for audit trail)
 CREATE TABLE IF NOT EXISTS infrastructure.circuit_breaker_events (
@@ -148,8 +148,8 @@ CREATE TABLE IF NOT EXISTS infrastructure.circuit_breaker_events (
     published_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
-CREATE INDEX idx_circuit_breaker_events_api_name ON infrastructure.circuit_breaker_events(api_name);
-CREATE INDEX idx_circuit_breaker_events_occurred_at ON infrastructure.circuit_breaker_events(occurred_at);
+CREATE INDEX IF NOT EXISTS idx_circuit_breaker_events_api_name ON infrastructure.circuit_breaker_events(api_name);
+CREATE INDEX IF NOT EXISTS idx_circuit_breaker_events_occurred_at ON infrastructure.circuit_breaker_events(occurred_at);
 
 -- ============================================================================
 -- OBSERVABILITY SCHEMA: Metrics & Monitoring
@@ -170,8 +170,8 @@ CREATE TABLE IF NOT EXISTS observability.batch_sla_metrics (
     published_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
-CREATE INDEX idx_batch_sla_job_name ON observability.batch_sla_metrics(job_name);
-CREATE INDEX idx_batch_sla_completed_at ON observability.batch_sla_metrics(completed_at);
+CREATE INDEX IF NOT EXISTS idx_batch_sla_job_name ON observability.batch_sla_metrics(job_name);
+CREATE INDEX IF NOT EXISTS idx_batch_sla_completed_at ON observability.batch_sla_metrics(completed_at);
 
 -- Data quality quarantine (rows marked for manual review)
 CREATE TABLE IF NOT EXISTS observability.data_quality_quarantine (
@@ -185,8 +185,8 @@ CREATE TABLE IF NOT EXISTS observability.data_quality_quarantine (
     published_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
-CREATE INDEX idx_data_quality_module ON observability.data_quality_quarantine(module_name);
-CREATE INDEX idx_data_quality_quarantined_at ON observability.data_quality_quarantine(quarantined_at);
+CREATE INDEX IF NOT EXISTS idx_data_quality_module ON observability.data_quality_quarantine(module_name);
+CREATE INDEX IF NOT EXISTS idx_data_quality_quarantined_at ON observability.data_quality_quarantine(quarantined_at);
 
 -- ============================================================================
 -- APPEND-ONLY AUDIT TRAIL (for all Phase 2-3 operations)
@@ -203,9 +203,9 @@ CREATE TABLE IF NOT EXISTS infrastructure.operation_audit_trail (
     published_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
-CREATE INDEX idx_operation_audit_type ON infrastructure.operation_audit_trail(operation_type);
-CREATE INDEX idx_operation_audit_correlation_id ON infrastructure.operation_audit_trail(correlation_id);
-CREATE INDEX idx_operation_audit_occurred_at ON infrastructure.operation_audit_trail(occurred_at);
+CREATE INDEX IF NOT EXISTS idx_operation_audit_type ON infrastructure.operation_audit_trail(operation_type);
+CREATE INDEX IF NOT EXISTS idx_operation_audit_correlation_id ON infrastructure.operation_audit_trail(correlation_id);
+CREATE INDEX IF NOT EXISTS idx_operation_audit_occurred_at ON infrastructure.operation_audit_trail(occurred_at);
 
 -- Permissions: schemas owned by executing role; no explicit role-based GRANT in dev/test
 -- In production, add explicit role-based GRANT via separate admin script after schema creation