address comments

bindinfo/bind_cache.go

@@ -80,7 +80,7 @@ func (c *bindCache) get(key bindCacheKey) []*BindRecord {
 func (c *bindCache) set(key bindCacheKey, value []*BindRecord) (ok bool, err error) {
 	mem := calcBindCacheKVMem(key, value)
 	if mem > c.memCapacity { // ignore this kv pair if its size is too large
-		err = errors.New("The memory usage of the binding_cache exceeds its capacity. The cache can't hold all of the available bindings")
+		err = errors.New("The memory usage of all available bindings exceeds the cache's mem quota. As a result, all available bindings cannot be held on the cache. Please increase the value of the system variable 'tidb_mem_quota_binding_cache' and execute 'admin reload bindings' to ensure that all bindings exist in the cache and can be used normally")
 		return
 	}
 	bindRecords := c.get(key)
@@ -89,7 +89,7 @@ func (c *bindCache) set(key bindCacheKey, value []*BindRecord) (ok bool, err err
 		mem -= calcBindCacheKVMem(key, bindRecords)
 	}
 	for mem+c.memTracker.BytesConsumed() > c.memCapacity {
-		err = errors.New("The memory usage of the binding_cache exceeds its capacity. The cache can't hold all of the available bindings")
+		err = errors.New("The memory usage of all available bindings exceeds the cache's mem quota. As a result, all available bindings cannot be held on the cache. Please increase the value of the system variable 'tidb_mem_quota_binding_cache' and execute 'admin reload bindings' to ensure that all bindings exist in the cache and can be used normally")
 		evictedKey, evictedValue, evicted := c.cache.RemoveOldest()
 		if !evicted {
 			return
@@ -211,7 +211,7 @@ func (c *bindCache) Copy() (newCache *bindCache, err error) {
 	defer c.lock.Unlock()
 	newCache = newBindCache()
 	if c.memTracker.BytesConsumed() > newCache.GetMemCapacity() {
-		err = errors.New("The memory usage of the binding_cache exceeds its capacity. The cache can't hold all of the available bindings")
+		err = errors.New("The memory usage of all available bindings exceeds the cache's mem quota. As a result, all available bindings cannot be held on the cache. Please increase the value of the system variable 'tidb_mem_quota_binding_cache' and execute 'admin reload bindings' to ensure that all bindings exist in the cache and can be used normally")
 	}
 	keys := c.cache.Keys()
 	for _, key := range keys {

bindinfo/session_handle.go

@@ -87,7 +87,8 @@ func (h *SessionHandle) DropBindRecord(originalSQL, db string, binding *Binding)
 	}
 	err := h.ch.SetBindRecord(hash, newRecord)
 	if err != nil {
-		logutil.BgLogger().Warn("[sql-bind] ", zap.Error(err))
+		// Should never reach here, just return an error for safety
+		return err
 	}
 	updateMetrics(metrics.ScopeSession, oldRecord, newRecord, false)
 	return nil