Merge remote-tracking branch 'main/0.5.1' into 0.5.1

Former-commit-id: bd6f86a733abce28e3d4a9c0cdad46f722683c95

CHANGELOG.md

@@ -5,6 +5,7 @@ Please mark all change in change log and use the ticket from JIRA.
 # Milvus 0.5.1 (TODO)
 
 ## Bug
+- \#90 - The server start error messages could be improved to enhance user experience
 - \#104 - test_scheduler core dump
 
 ## Improvement

README.md

@@ -20,7 +20,7 @@
 
 ## What is Milvus
 
-Milvus is an open source similarity search engine for massive feature vectors. Designed with heterogeneous computing architecture for the best cost efficiency. Searches over billion-scale vectors take only milliseconds with minimum computing resources.
+Milvus is an open source similarity search engine for massive-scale feature vectors. Built with heterogeneous computing architecture for the best cost efficiency. Searches over billion-scale vectors take only milliseconds with minimum computing resources.
 
 Milvus provides stable Python, Java and C++ APIs.
 
@@ -28,7 +28,7 @@ Keep up-to-date with newest releases and latest updates by reading Milvus [relea
 
 - Heterogeneous computing
 
-  Milvus is designed with heterogeneous computing architecture for the best performance and cost efficiency. 
+  Milvus is built with heterogeneous computing architecture for the best performance and cost efficiency. 
 
 - Multiple indexes
 
@@ -64,14 +64,14 @@ Keep up-to-date with newest releases and latest updates by reading Milvus [relea
 
 ## Get started
 
-### Hardware Requirements
+### Hardware requirements
 
 | Component | Recommended configuration           |
 | --------- | ----------------------------------- |
 | CPU       | Intel CPU Haswell or higher         |
 | GPU       | NVIDIA Pascal series or higher      |
-| Memory    | 8 GB or more (depends on data size) |
-| Storage   | SATA 3.0 SSD or higher              |
+| RAM       | 8 GB or more (depends on data size) |
+| Hard drive| SATA 3.0 SSD or higher              |
 
 ### Install using docker
 
@@ -168,6 +168,10 @@ Make sure Java 8 or higher is already installed.
 
 Refer to [this link](https://github.com/milvus-io/milvus-sdk-java/tree/master/examples) for the example code.
 
+## Milvus roadmap
+
+Please read our [roadmap](https://milvus.io/docs/en/roadmap/) to learn about upcoming features.
+
 ## Contribution guidelines
 
 Contributions are welcomed and greatly appreciated. Please read our [contribution guidelines](CONTRIBUTING.md) for detailed contribution workflow. This project adheres to the [code of conduct](CODE_OF_CONDUCT.md) of Milvus. By participating, you are expected to uphold this code.
@@ -178,9 +182,11 @@ We use [GitHub issues](https://github.com/milvus-io/milvus/issues/new/choose) to
 
 To connect with other users and contributors, welcome to join our [slack channel](https://join.slack.com/t/milvusio/shared_invite/enQtNzY1OTQ0NDI3NjMzLWNmYmM1NmNjOTQ5MGI5NDhhYmRhMGU5M2NhNzhhMDMzY2MzNDdlYjM5ODQ5MmE3ODFlYzU3YjJkNmVlNDQ2ZTk). 
 
-## Milvus Roadmap
+## Thanks
 
-Please read our [roadmap](https://milvus.io/docs/en/roadmap/) to learn about upcoming features.
+We greatly appreciate the help of the following people.
+
+- [akihoni](https://github.com/akihoni) found a broken link and a small typo in the README file.
 
 ## Resources
 
@@ -196,7 +202,6 @@ Please read our [roadmap](https://milvus.io/docs/en/roadmap/) to learn about upc
 
 [Milvus roadmap](https://milvus.io/docs/en/roadmap/)
 
-
 ## License
 
 [Apache License 2.0](LICENSE)

core/conf/server_config.template

@@ -2,9 +2,9 @@
 
 server_config:
   address: 0.0.0.0                  # milvus server ip address (IPv4)
-  port: 19530                       # port range: 1025 ~ 65534
+  port: 19530                       # milvus server port, must in range [1025, 65534]
   deploy_mode: single               # deployment type: single, cluster_readonly, cluster_writable
-  time_zone: UTC+8
+  time_zone: UTC+8                  # time zone, must be in format: UTC+X
 
 db_config:
   primary_path: @MILVUS_DB_PATH@    # path used to store data and meta
@@ -14,30 +14,30 @@ db_config:
                                     # Keep 'dialect://:@:/', and replace other texts with real values
                                     # Replace 'dialect' with 'mysql' or 'sqlite'
 
-  insert_buffer_size: 4             # GB, maximum insert buffer size allowed
+  insert_buffer_size: 4             # GB, maximum insert buffer size allowed, must be a positive integer
                                     # sum of insert_buffer_size and cpu_cache_capacity cannot exceed total memory
 
   preload_table:                    # preload data at startup, '*' means load all tables, empty value means no preload
                                     # you can specify preload tables like this: table1,table2,table3
 
 metric_config:
-  enable_monitor: false             # enable monitoring or not
+  enable_monitor: false             # enable monitoring or not, must be a boolean
   collector: prometheus             # prometheus
   prometheus_config:
-    port: 8080                      # port prometheus uses to fetch metrics
+    port: 8080                      # port prometheus uses to fetch metrics, must in range [1025, 65534]
 
 cache_config:
-  cpu_cache_capacity: 16            # GB, CPU memory used for cache
-  cpu_cache_threshold: 0.85         # percentage of data that will be kept when cache cleanup is triggered
-  gpu_cache_capacity: 4             # GB, GPU memory used for cache
-  gpu_cache_threshold: 0.85         # percentage of data that will be kept when cache cleanup is triggered
-  cache_insert_data: false          # whether to load inserted data into cache
+  cpu_cache_capacity: 16            # GB, CPU memory used for cache, must be a positive integer
+  cpu_cache_threshold: 0.85         # percentage of data that will be kept when cache cleanup is triggered, must be in range (0.0, 1.0]
+  gpu_cache_capacity: 4             # GB, GPU memory used for cache, must be a positive integer
+  gpu_cache_threshold: 0.85         # percentage of data that will be kept when cache cleanup is triggered, must be in range (0.0, 1.0]
+  cache_insert_data: false          # whether to load inserted data into cache, must be a boolean
 
 engine_config:
   use_blas_threshold: 20            # if nq <  use_blas_threshold, use SSE, faster with fluctuated response times
                                     # if nq >= use_blas_threshold, use OpenBlas, slower with stable response times
 
 resource_config:
-  search_resources:                 # define the GPUs used for search computation, valid value: gpux
+  search_resources:                 # define the GPUs used for search computation, must be in format: gpux
     - gpu0
-  index_build_device: gpu0          # GPU used for building index
\ No newline at end of file
+  index_build_device: gpu0          # GPU used for building index, must be in format: gpux
\ No newline at end of file

core/src/scheduler/job/Job.cpp

@@ -15,7 +15,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-#include "Job.h"
+#include "scheduler/job/Job.h"
 
 namespace milvus {
 namespace scheduler {

core/src/server/Config.cpp

@@ -363,7 +363,9 @@ Config::PrintAll() {
 Status
 Config::CheckServerConfigAddress(const std::string& value) {
     if (!ValidationUtil::ValidateIpAddress(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid server config address: " + value);
+        std::string msg =
+            "Invalid server IP address: " + value + ". Possible reason: server_config.address is invalid.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -371,11 +373,14 @@ Config::CheckServerConfigAddress(const std::string& value) {
 Status
 Config::CheckServerConfigPort(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid server config port: " + value);
+        std::string msg = "Invalid server port: " + value + ". Possible reason: server_config.port is not a number.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     } else {
         int32_t port = std::stoi(value);
         if (!(port > 1024 && port < 65535)) {
-            return Status(SERVER_INVALID_ARGUMENT, "Server config port out of range (1024, 65535): " + value);
+            std::string msg = "Invalid server port: " + value +
+                              ". Possible reason: server_config.port is not in range [1025, 65534].";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
         }
     }
     return Status::OK();
@@ -385,7 +390,8 @@ Status
 Config::CheckServerConfigDeployMode(const std::string& value) {
     if (value != "single" && value != "cluster_readonly" && value != "cluster_writable") {
         return Status(SERVER_INVALID_ARGUMENT,
-                      "Invalid server config mode [single, cluster_readonly, cluster_writable]: " + value);
+                      "server_config.deploy_mode is not one of "
+                      "single, cluster_readonly, and cluster_writable.");
     }
     return Status::OK();
 }
@@ -393,15 +399,15 @@ Config::CheckServerConfigDeployMode(const std::string& value) {
 Status
 Config::CheckServerConfigTimeZone(const std::string& value) {
     if (value.length() <= 3) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid server config time_zone: " + value);
+        return Status(SERVER_INVALID_ARGUMENT, "Invalid server_config.time_zone: " + value);
     } else {
         if (value.substr(0, 3) != "UTC") {
-            return Status(SERVER_INVALID_ARGUMENT, "Invalid server config time_zone: " + value);
+            return Status(SERVER_INVALID_ARGUMENT, "Invalid server_config.time_zone: " + value);
         } else {
             try {
                 stoi(value.substr(3));
             } catch (...) {
-                return Status(SERVER_INVALID_ARGUMENT, "Invalid server config time_zone: " + value);
+                return Status(SERVER_INVALID_ARGUMENT, "Invalid server_config.time_zone: " + value);
             }
         }
     }
@@ -411,7 +417,7 @@ Config::CheckServerConfigTimeZone(const std::string& value) {
 Status
 Config::CheckDBConfigPrimaryPath(const std::string& value) {
     if (value.empty()) {
-        return Status(SERVER_INVALID_ARGUMENT, "DB config primary_path empty");
+        return Status(SERVER_INVALID_ARGUMENT, "db_config.db_path is empty.");
     }
     return Status::OK();
 }
@@ -424,7 +430,10 @@ Config::CheckDBConfigSecondaryPath(const std::string& value) {
 Status
 Config::CheckDBConfigBackendUrl(const std::string& value) {
     if (!ValidationUtil::ValidateDbURI(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid DB config backend_url: " + value);
+        std::string msg =
+            "Invalid backend url: " + value + ". Possible reason: db_config.db_backend_url is invalid. " +
+            "The correct format should be like sqlite://:@:/ or mysql://root:123456@127.0.0.1:3306/milvus.";
+        return Status(SERVER_INVALID_ARGUMENT, "invalid db_backend_url: " + value);
     }
     return Status::OK();
 }
@@ -432,7 +441,9 @@ Config::CheckDBConfigBackendUrl(const std::string& value) {
 Status
 Config::CheckDBConfigArchiveDiskThreshold(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid DB config archive_disk_threshold: " + value);
+        std::string msg = "Invalid archive disk threshold: " + value +
+                          ". Possible reason: db_config.archive_disk_threshold is invalid.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -440,7 +451,9 @@ Config::CheckDBConfigArchiveDiskThreshold(const std::string& value) {
 Status
 Config::CheckDBConfigArchiveDaysThreshold(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid DB config archive_days_threshold: " + value);
+        std::string msg = "Invalid archive days threshold: " + value +
+                          ". Possible reason: db_config.archive_disk_threshold is invalid.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -448,13 +461,23 @@ Config::CheckDBConfigArchiveDaysThreshold(const std::string& value) {
 Status
 Config::CheckDBConfigInsertBufferSize(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid DB config insert_buffer_size: " + value);
+        std::string msg = "Invalid insert buffer size: " + value +
+                          ". Possible reason: db_config.insert_buffer_size is not a positive integer.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     } else {
         int64_t buffer_size = std::stoi(value) * GB;
+        if (buffer_size <= 0) {
+            std::string msg = "Invalid insert buffer size: " + value +
+                              ". Possible reason: db_config.insert_buffer_size is not a positive integer.";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
+        }
+
         uint64_t total_mem = 0, free_mem = 0;
         CommonUtil::GetSystemMemInfo(total_mem, free_mem);
         if (buffer_size >= total_mem) {
-            return Status(SERVER_INVALID_ARGUMENT, "DB config insert_buffer_size exceed system memory: " + value);
+            std::string msg = "Invalid insert buffer size: " + value +
+                              ". Possible reason: db_config.insert_buffer_size exceeds system memory.";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
         }
     }
     return Status::OK();
@@ -463,7 +486,9 @@ Config::CheckDBConfigInsertBufferSize(const std::string& value) {
 Status
 Config::CheckMetricConfigEnableMonitor(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsBool(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid metric config auto_bootup: " + value);
+        std::string msg =
+            "Invalid metric config: " + value + ". Possible reason: metric_config.enable_monitor is not a boolean.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -471,7 +496,9 @@ Config::CheckMetricConfigEnableMonitor(const std::string& value) {
 Status
 Config::CheckMetricConfigCollector(const std::string& value) {
     if (value != "prometheus") {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid metric config collector: " + value);
+        std::string msg =
+            "Invalid metric collector: " + value + ". Possible reason: metric_config.collector is invalid.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -479,6 +506,8 @@ Config::CheckMetricConfigCollector(const std::string& value) {
 Status
 Config::CheckMetricConfigPrometheusPort(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
+        std::string msg = "Invalid metric port: " + value +
+                          ". Possible reason: metric_config.prometheus_config.port is not in range [1025, 65534].";
         return Status(SERVER_INVALID_ARGUMENT, "Invalid metric config prometheus_port: " + value);
     }
     return Status::OK();
@@ -487,15 +516,25 @@ Config::CheckMetricConfigPrometheusPort(const std::string& value) {
 Status
 Config::CheckCacheConfigCpuCacheCapacity(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid cache config cpu_cache_capacity: " + value);
+        std::string msg = "Invalid cpu cache capacity: " + value +
+                          ". Possible reason: cache_config.cpu_cache_capacity is not a positive integer.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     } else {
-        uint64_t cpu_cache_capacity = std::stoi(value) * GB;
+        int64_t cpu_cache_capacity = std::stoi(value) * GB;
+        if (cpu_cache_capacity <= 0) {
+            std::string msg = "Invalid cpu cache capacity: " + value +
+                              ". Possible reason: cache_config.cpu_cache_capacity is not a positive integer.";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
+        }
+
         uint64_t total_mem = 0, free_mem = 0;
         CommonUtil::GetSystemMemInfo(total_mem, free_mem);
-        if (cpu_cache_capacity >= total_mem) {
-            return Status(SERVER_INVALID_ARGUMENT, "Cache config cpu_cache_capacity exceed system memory: " + value);
-        } else if (cpu_cache_capacity > static_cast<double>(total_mem * 0.9)) {
-            std::cerr << "Warning: cpu_cache_capacity value is too big" << std::endl;
+        if (static_cast<uint64_t>(cpu_cache_capacity) >= total_mem) {
+            std::string msg = "Invalid cpu cache capacity: " + value +
+                              ". Possible reason: cache_config.cpu_cache_capacity exceeds system memory.";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
+        } else if (static_cast<double>(cpu_cache_capacity) > static_cast<double>(total_mem * 0.9)) {
+            std::cerr << "WARNING: cpu cache capacity value is too big" << std::endl;
         }
 
         int32_t buffer_value;
@@ -506,7 +545,10 @@ Config::CheckCacheConfigCpuCacheCapacity(const std::string& value) {
 
         int64_t insert_buffer_size = buffer_value * GB;
         if (insert_buffer_size + cpu_cache_capacity >= total_mem) {
-            return Status(SERVER_INVALID_ARGUMENT, "Sum of cpu_cache_capacity and buffer_size exceed system memory");
+            std::string msg = "Invalid cpu cache capacity: " + value +
+                              ". Possible reason: sum of cache_config.cpu_cache_capacity and "
+                              "db_config.insert_buffer_size exceeds system memory.";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
         }
     }
     return Status::OK();
@@ -515,11 +557,15 @@ Config::CheckCacheConfigCpuCacheCapacity(const std::string& value) {
 Status
 Config::CheckCacheConfigCpuCacheThreshold(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsFloat(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid cache config cpu_cache_threshold: " + value);
+        std::string msg = "Invalid cpu cache threshold: " + value +
+                          ". Possible reason: cache_config.cpu_cache_threshold is not in range (0.0, 1.0].";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     } else {
         float cpu_cache_threshold = std::stof(value);
         if (cpu_cache_threshold <= 0.0 || cpu_cache_threshold >= 1.0) {
-            return Status(SERVER_INVALID_ARGUMENT, "Invalid cache config cpu_cache_threshold: " + value);
+            std::string msg = "Invalid cpu cache threshold: " + value +
+                              ". Possible reason: cache_config.cpu_cache_threshold is not in range (0.0, 1.0].";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
         }
     }
     return Status::OK();
@@ -528,7 +574,9 @@ Config::CheckCacheConfigCpuCacheThreshold(const std::string& value) {
 Status
 Config::CheckCacheConfigGpuCacheCapacity(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid cache config gpu_cache_capacity: " + value);
+        std::string msg = "Invalid gpu cache capacity: " + value +
+                          ". Possible reason: cache_config.gpu_cache_capacity is not a positive integer.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     } else {
         uint64_t gpu_cache_capacity = std::stoi(value) * GB;
         int gpu_index;
@@ -539,13 +587,14 @@ Config::CheckCacheConfigGpuCacheCapacity(const std::string& value) {
 
         size_t gpu_memory;
         if (!ValidationUtil::GetGpuMemory(gpu_index, gpu_memory).ok()) {
-            return Status(SERVER_UNEXPECTED_ERROR,
-                          "Fail to get GPU memory for GPU device: " + std::to_string(gpu_index));
+            std::string msg = "Fail to get GPU memory for GPU device: " + std::to_string(gpu_index);
+            return Status(SERVER_UNEXPECTED_ERROR, msg);
         } else if (gpu_cache_capacity >= gpu_memory) {
-            return Status(SERVER_INVALID_ARGUMENT,
-                          "Cache config gpu_cache_capacity exceed GPU memory: " + std::to_string(gpu_memory));
+            std::string msg = "Invalid gpu cache capacity: " + value +
+                              ". Possible reason: cache_config.gpu_cache_capacity exceeds GPU memory.";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
         } else if (gpu_cache_capacity > (double)gpu_memory * 0.9) {
-            std::cerr << "Warning: gpu_cache_capacity value is too big" << std::endl;
+            std::cerr << "Warning: gpu cache capacity value is too big" << std::endl;
         }
     }
     return Status::OK();
@@ -554,11 +603,15 @@ Config::CheckCacheConfigGpuCacheCapacity(const std::string& value) {
 Status
 Config::CheckCacheConfigGpuCacheThreshold(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsFloat(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid cache config gpu_cache_threshold: " + value);
+        std::string msg = "Invalid gpu cache threshold: " + value +
+                          ". Possible reason: cache_config.gpu_cache_threshold is not in range (0.0, 1.0].";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     } else {
         float gpu_cache_threshold = std::stof(value);
         if (gpu_cache_threshold <= 0.0 || gpu_cache_threshold >= 1.0) {
-            return Status(SERVER_INVALID_ARGUMENT, "Invalid cache config gpu_cache_threshold: " + value);
+            std::string msg = "Invalid gpu cache threshold: " + value +
+                              ". Possible reason: cache_config.gpu_cache_threshold is not in range (0.0, 1.0].";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
         }
     }
     return Status::OK();
@@ -567,7 +620,9 @@ Config::CheckCacheConfigGpuCacheThreshold(const std::string& value) {
 Status
 Config::CheckCacheConfigCacheInsertData(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsBool(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid cache config cache_insert_data: " + value);
+        std::string msg = "Invalid cache insert option: " + value +
+                          ". Possible reason: cache_config.cache_insert_data is not a boolean.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -575,7 +630,9 @@ Config::CheckCacheConfigCacheInsertData(const std::string& value) {
 Status
 Config::CheckEngineConfigUseBlasThreshold(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid engine config use_blas_threshold: " + value);
+        std::string msg = "Invalid blas threshold: " + value +
+                          ". Possible reason: engine_config.use_blas_threshold is not a positive integer.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -583,14 +640,18 @@ Config::CheckEngineConfigUseBlasThreshold(const std::string& value) {
 Status
 Config::CheckEngineConfigOmpThreadNum(const std::string& value) {
     if (!ValidationUtil::ValidateStringIsNumber(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid engine config omp_thread_num: " + value);
+        std::string msg = "Invalid omp thread number: " + value +
+                          ". Possible reason: engine_config.omp_thread_num is not a positive integer.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
 
     int32_t omp_thread = std::stoi(value);
     uint32_t sys_thread_cnt = 8;
     CommonUtil::GetSystemAvailableThreads(sys_thread_cnt);
     if (omp_thread > static_cast<int32_t>(sys_thread_cnt)) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid engine config omp_thread_num: " + value);
+        std::string msg = "Invalid omp thread number: " + value +
+                          ". Possible reason: engine_config.omp_thread_num exceeds system cpu cores.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -598,7 +659,8 @@ Config::CheckEngineConfigOmpThreadNum(const std::string& value) {
 Status
 Config::CheckResourceConfigMode(const std::string& value) {
     if (value != "simple") {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid resource config mode: " + value);
+        std::string msg = "Invalid resource mode: " + value + ". Possible reason: resource_config.mode is invalid.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -608,12 +670,16 @@ CheckGpuDevice(const std::string& value) {
     const std::regex pat("gpu(\\d+)");
     std::cmatch m;
     if (!std::regex_match(value.c_str(), m, pat)) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid gpu device: " + value);
+        std::string msg = "Invalid gpu device: " + value +
+                          ". Possible reason: resource_config.search_resources does not match your hardware.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
 
     int32_t gpu_index = std::stoi(value.substr(3));
     if (!ValidationUtil::ValidateGpuIndex(gpu_index).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid gpu device: " + value);
+        std::string msg = "Invalid gpu device: " + value +
+                          ". Possible reason: resource_config.search_resources does not match your hardware.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }
@@ -621,12 +687,17 @@ CheckGpuDevice(const std::string& value) {
 Status
 Config::CheckResourceConfigSearchResources(const std::vector<std::string>& value) {
     if (value.empty()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Empty resource config search_resources");
+        std::string msg =
+            "Invalid search resource. "
+            "Possible reason: resource_config.search_resources is empty.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
 
     for (auto& gpu_device : value) {
         if (!CheckGpuDevice(gpu_device).ok()) {
-            return Status(SERVER_INVALID_ARGUMENT, "Invalid resource config search_resources: " + gpu_device);
+            std::string msg = "Invalid search resource: " + gpu_device +
+                              ". Possible reason: resource_config.search_resources does not match your hardware.";
+            return Status(SERVER_INVALID_ARGUMENT, msg);
         }
     }
     return Status::OK();
@@ -635,7 +706,9 @@ Config::CheckResourceConfigSearchResources(const std::vector<std::string>& value
 Status
 Config::CheckResourceConfigIndexBuildDevice(const std::string& value) {
     if (!CheckGpuDevice(value).ok()) {
-        return Status(SERVER_INVALID_ARGUMENT, "Invalid resource config index_build_device: " + value);
+        std::string msg = "Invalid index build device: " + value +
+                          ". Possible reason: resource_config.index_build_device does not match your hardware.";
+        return Status(SERVER_INVALID_ARGUMENT, msg);
     }
     return Status::OK();
 }

core/src/server/DBWrapper.cpp

@@ -40,12 +40,14 @@ DBWrapper::StartService() {
     engine::DBOptions opt;
     s = config.GetDBConfigBackendUrl(opt.meta_.backend_uri_);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 
     std::string path;
     s = config.GetDBConfigPrimaryPath(path);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 
@@ -54,6 +56,7 @@ DBWrapper::StartService() {
     std::string db_slave_path;
     s = config.GetDBConfigSecondaryPath(db_slave_path);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 
@@ -62,12 +65,14 @@ DBWrapper::StartService() {
     // cache config
     s = config.GetCacheConfigCacheInsertData(opt.insert_cache_immediately_);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 
     std::string mode;
     s = config.GetServerConfigDeployMode(mode);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 
@@ -78,8 +83,8 @@ DBWrapper::StartService() {
     } else if (mode == "cluster_writable") {
         opt.mode_ = engine::DBOptions::MODE::CLUSTER_WRITABLE;
     } else {
-        std::cerr << "ERROR: mode specified in server_config must be ['single', 'cluster_readonly', 'cluster_writable']"
-                  << std::endl;
+        std::cerr << "Error: server_config.deploy_mode in server_config.yaml is not one of "
+                  << "single, cluster_readonly, and cluster_writable." << std::endl;
         kill(0, SIGUSR1);
     }
 
@@ -87,6 +92,7 @@ DBWrapper::StartService() {
     int32_t omp_thread;
     s = config.GetEngineConfigOmpThreadNum(omp_thread);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 
@@ -105,6 +111,7 @@ DBWrapper::StartService() {
     int32_t use_blas_threshold;
     s = config.GetEngineConfigUseBlasThreshold(use_blas_threshold);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 
@@ -115,6 +122,7 @@ DBWrapper::StartService() {
     int32_t disk, days;
     s = config.GetDBConfigArchiveDiskThreshold(disk);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 
@@ -124,6 +132,7 @@ DBWrapper::StartService() {
 
     s = config.GetDBConfigArchiveDaysThreshold(days);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 
@@ -133,16 +142,20 @@ DBWrapper::StartService() {
     opt.meta_.archive_conf_.SetCriterias(criterial);
 
     // create db root folder
-    Status status = CommonUtil::CreateDirectory(opt.meta_.path_);
-    if (!status.ok()) {
-        std::cerr << "ERROR! Failed to create database root path: " << opt.meta_.path_ << std::endl;
+    s = CommonUtil::CreateDirectory(opt.meta_.path_);
+    if (!s.ok()) {
+        std::cerr << "Error: Failed to create database primary path: " << path
+                  << ". Possible reason: db_config.primary_path is wrong in server_config.yaml or not available."
+                  << std::endl;
         kill(0, SIGUSR1);
     }
 
     for (auto& path : opt.meta_.slave_paths_) {
-        status = CommonUtil::CreateDirectory(path);
-        if (!status.ok()) {
-            std::cerr << "ERROR! Failed to create database slave path: " << path << std::endl;
+        s = CommonUtil::CreateDirectory(path);
+        if (!s.ok()) {
+            std::cerr << "Error: Failed to create database secondary path: " << path
+                      << ". Possible reason: db_config.secondary_path is wrong in server_config.yaml or not available."
+                      << std::endl;
             kill(0, SIGUSR1);
         }
     }
@@ -151,7 +164,8 @@ DBWrapper::StartService() {
     try {
         db_ = engine::DBFactory::Build(opt);
     } catch (std::exception& ex) {
-        std::cerr << "ERROR! Failed to open database: " << ex.what() << std::endl;
+        std::cerr << "Error: failed to open database: " << ex.what()
+                  << ". Possible reason: the meta system does not work." << std::endl;
         kill(0, SIGUSR1);
     }
 
@@ -161,6 +175,7 @@ DBWrapper::StartService() {
     std::string preload_tables;
     s = config.GetDBConfigPreloadTable(preload_tables);
     if (!s.ok()) {
+        std::cerr << s.ToString() << std::endl;
         return s;
     }
 

core/unittest/db/utils.cpp

@@ -68,7 +68,7 @@ static const char
                    "  blas_threshold: 20\n"
                    "\n"
                    "resource_config:\n"
-                   "  resource_pool:\n"
+                   "  search_resources:\n"
                    "    - gpu0\n"
                    "  index_build_device: gpu0          # GPU used for building index";
 

core/unittest/wrapper/utils.cpp

@@ -58,7 +58,7 @@ static const char
                    "  blas_threshold: 20\n"
                    "\n"
                    "resource_config:\n"
-                   "  resource_pool:\n"
+                   "  search_resources:\n"
                    "    - gpu0\n"
                    "  index_build_device: gpu0          # GPU used for building index";