Improved configuration file description (#1840)

docs-2.0/5.configurations-and-logs/1.configurations/4.storage-config.md

@@ -27,7 +27,7 @@ For all parameters and their current values, see [Configurations](1.configuratio
 | :----------- | :----------------------- | :------------------|
 | `daemonize`  | `true`                   | When set to `true`, the process is a daemon process. |
 | `pid_file`   | `pids/nebula-storaged.pid` | The file that records the process ID. |
-| `timezone_name` | - | Specifies the NebulaGraph time zone. This parameter is not predefined in the initial configuration files. The system default value is `UTC+00:00:00`. For the format of the parameter value, see [Specifying the Time Zone with TZ](https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html "Click to view the timezone-related content in the GNU C Library manual"). For example, `--timezone_name=UTC+08:00` represents the GMT+8 time zone. |
+| `timezone_name` | `UTC+00:00:00` | Specifies the NebulaGraph time zone. This parameter is not predefined in the initial configuration files, if you need to use this parameter, add it manually. For the format of the parameter value, see [Specifying the Time Zone with TZ](https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html "Click to view the timezone-related content in the GNU C Library manual"). For example, `--timezone_name=UTC+08:00` represents the GMT+8 time zone. |
 | `local_config` | `true` | When set to `true`, the process gets configurations from the configuration files. |
 
 !!! note
@@ -82,14 +82,14 @@ For all parameters and their current values, see [Configurations](1.configuratio
 | `rocksdb_block_cache`            | `4` | Specifies the block cache for BlockBasedTable. The configuration is measured in megabytes.|
 |`disable_page_cache`              |`false`|Enables or disables the operating system's page cache for NebulaGraph. By default, the parameter value is `false` and page cache is enabled. If the value is set to `true`, page cache is disabled and sufficient block cache space must be configured for NebulaGraph.|
 | `engine_type`                    | `rocksdb` | Specifies the engine type. |
-| `rocksdb_compression`            | `lz4` | Specifies the compression algorithm for RocksDB. Optional values are `no`, `snappy`, `lz4`, `lz4hc`, `zlib`, `bzip2`, and `zstd`. |
-| `rocksdb_compression_per_level`  | \ | Specifies the compression algorithm for each level. |
+| `rocksdb_compression`            | `lz4` | Specifies the compression algorithm for RocksDB. Optional values are `no`, `snappy`, `lz4`, `lz4hc`, `zlib`, `bzip2`, and `zstd`.<br>This parameter modifies the compression algorithm for each level. If you want to set different compression algorithms for each level, use the parameter `rocksdb_compression_per_level`. |
+| `rocksdb_compression_per_level`  | \ | Specifies the compression algorithm for each level. The priority is higher than `rocksdb_compression`. For example, `no:no:lz4:lz4:snappy:zstd:snappy`.<br>You can also not set certain levels of compression algorithms, for example, `no:no:lz4:lz4::zstd`, level L4 and L6 use the compression algorithm of `rocksdb_compression`. |
 |`enable_rocksdb_statistics`       | `false` | When set to `false`, RocksDB statistics is disabled. |
 | `rocksdb_stats_level`            | `kExceptHistogramOrTimers` | Specifies the stats level for RocksDB. Optional values are `kExceptHistogramOrTimers`, `kExceptTimers`, `kExceptDetailedTimers`, `kExceptTimeForMutex`, and `kAll`. |
 | `enable_rocksdb_prefix_filtering` | `true` | When set to `true`, the prefix bloom filter for RocksDB is enabled. Enabling prefix bloom filter makes the graph traversal faster but occupies more memory.  |
 |`enable_rocksdb_whole_key_filtering` | `false` | When set to `true`, the whole key bloom filter for RocksDB is enabled. |
 | `rocksdb_filtering_prefix_length` | `12` | Specifies the prefix length for each key. Optional values are `12` and `16`. The configuration is measured in bytes. |
-| `enable_partitioned_index_filter` | - | When set to `true`, it reduces the amount of memory used by the bloom filter. But in some random-seek situations, it may reduce the read performance. |
+| `enable_partitioned_index_filter` | `false` | When set to `true`, it reduces the amount of memory used by the bloom filter. But in some random-seek situations, it may reduce the read performance. This parameter is not predefined in the initial configuration files, if you need to use this parameter, add it manually.|
 
 <!-- unhide until the kv separation bug is fixed
  ## Key-Value separation configurations
@@ -211,7 +211,7 @@ When the query starting from each vertex gets an edge, truncate it directly to a
 
 | Property name                   | Default value                    | Description  |
 | :------------------- | :------------------------ | :------------------------------------------ |
-| max_edge_returned_per_vertex | 2147483647 | Specifies the maximum number of edges returned for each dense vertex. Excess edges are truncated and not returned. This parameter is not predefined in the configuration files. |
+| max_edge_returned_per_vertex | `2147483647` | Specifies the maximum number of edges returned for each dense vertex. Excess edges are truncated and not returned. This parameter is not predefined in the initial configuration files, if you need to use this parameter, add it manually. |
 
 ## Storage configurations for large dataset