chore: update config docs and test

Signed-off-by: evenyag <[email protected]>

Author: evenyag

config/config.md

@@ -151,6 +151,8 @@
 | `region_engine.mito.write_cache_path` | String | `""` | File system path for write cache, defaults to `{data_home}`. |
 | `region_engine.mito.write_cache_size` | String | `5GiB` | Capacity for write cache. If your disk space is sufficient, it is recommended to set it larger. |
 | `region_engine.mito.write_cache_ttl` | String | Unset | TTL for write cache. |
+| `region_engine.mito.preload_index_cache` | Bool | `true` | Preload index (puffin) files into cache on region open (default: true).<br/>When enabled, index files are loaded into the write cache during region initialization,<br/>which can improve query performance at the cost of longer startup times. |
+| `region_engine.mito.index_cache_percent` | Integer | `20` | Percentage of write cache capacity allocated for index (puffin) files (default: 20).<br/>The remaining capacity is used for data (parquet) files.<br/>Must be between 0 and 100 (exclusive). For example, with a 5GiB write cache and 20% allocation,<br/>1GiB is reserved for index files and 4GiB for data files. |
 | `region_engine.mito.sst_write_buffer_size` | String | `8MB` | Buffer size for SST writing. |
 | `region_engine.mito.parallel_scan_channel_size` | Integer | `32` | Capacity of the channel to send data from parallel scan tasks to the main task. |
 | `region_engine.mito.max_concurrent_scan_files` | Integer | `384` | Maximum number of SST files to scan concurrently. |
@@ -549,6 +551,8 @@
 | `region_engine.mito.write_cache_path` | String | `""` | File system path for write cache, defaults to `{data_home}`. |
 | `region_engine.mito.write_cache_size` | String | `5GiB` | Capacity for write cache. If your disk space is sufficient, it is recommended to set it larger. |
 | `region_engine.mito.write_cache_ttl` | String | Unset | TTL for write cache. |
+| `region_engine.mito.preload_index_cache` | Bool | `true` | Preload index (puffin) files into cache on region open (default: true).<br/>When enabled, index files are loaded into the write cache during region initialization,<br/>which can improve query performance at the cost of longer startup times. |
+| `region_engine.mito.index_cache_percent` | Integer | `20` | Percentage of write cache capacity allocated for index (puffin) files (default: 20).<br/>The remaining capacity is used for data (parquet) files.<br/>Must be between 0 and 100 (exclusive). For example, with a 5GiB write cache and 20% allocation,<br/>1GiB is reserved for index files and 4GiB for data files. |
 | `region_engine.mito.sst_write_buffer_size` | String | `8MB` | Buffer size for SST writing. |
 | `region_engine.mito.parallel_scan_channel_size` | Integer | `32` | Capacity of the channel to send data from parallel scan tasks to the main task. |
 | `region_engine.mito.max_concurrent_scan_files` | Integer | `384` | Maximum number of SST files to scan concurrently. |

config/datanode.example.toml

@@ -489,6 +489,17 @@ write_cache_size = "5GiB"
 ## @toml2docs:none-default
 write_cache_ttl = "8h"
 
+## Preload index (puffin) files into cache on region open (default: true).
+## When enabled, index files are loaded into the write cache during region initialization,
+## which can improve query performance at the cost of longer startup times.
+preload_index_cache = true
+
+## Percentage of write cache capacity allocated for index (puffin) files (default: 20).
+## The remaining capacity is used for data (parquet) files.
+## Must be between 0 and 100 (exclusive). For example, with a 5GiB write cache and 20% allocation,
+## 1GiB is reserved for index files and 4GiB for data files.
+index_cache_percent = 20
+
 ## Buffer size for SST writing.
 sst_write_buffer_size = "8MB"
 

config/standalone.example.toml

@@ -580,6 +580,17 @@ write_cache_size = "5GiB"
 ## @toml2docs:none-default
 write_cache_ttl = "8h"
 
+## Preload index (puffin) files into cache on region open (default: true).
+## When enabled, index files are loaded into the write cache during region initialization,
+## which can improve query performance at the cost of longer startup times.
+preload_index_cache = true
+
+## Percentage of write cache capacity allocated for index (puffin) files (default: 20).
+## The remaining capacity is used for data (parquet) files.
+## Must be between 0 and 100 (exclusive). For example, with a 5GiB write cache and 20% allocation,
+## 1GiB is reserved for index files and 4GiB for data files.
+index_cache_percent = 20
+
 ## Buffer size for SST writing.
 sst_write_buffer_size = "8MB"
 

tests-integration/tests/http.rs

@@ -1497,6 +1497,8 @@ auto_flush_interval = "30m"
 enable_write_cache = false
 write_cache_path = ""
 write_cache_size = "5GiB"
+preload_index_cache = true
+index_cache_percent = 20
 sst_write_buffer_size = "8MiB"
 parallel_scan_channel_size = 32
 max_concurrent_scan_files = 384