# `VERSION::7.5.0` Controlling the Statistics Initial Load Behavior

+ **`performance.force-init-stats`**: Waiting for the statistics to be loaded into memory before accepting incoming requests 
    + TRUE: The TiDB Server will wait for the complete loading of all statistics into memory before initiating its services. 
    + FALSE: The TiDB Server will commence service provision immediately after startup, irrespective of the status of the statistics loading.
+ **`performance.lite-init-stats`**: Loading the basic statistics or primary statistics before accepting incoming requests
  + TRUE: This setting prevents the loading of any histograms, TopN, or Count-Min Sketch of indexes or columns into memory.
  + FALSE: In this configuration, histograms, TopN, and Count-Min Sketch data for indexes and primary keys are loaded into memory, while such data for non-primary key columns remain unloaded.
+ The supplemental statistics are never loaded during TiDB server startup but are instead loaded when referenced by a query
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Configuration Parameter: `performance.force-init-stats`
- `TRUE`: The TiDB Server will wait for the complete loading of all statistics into memory before initiating its services. This procedure is referred to as statistics initialization.
- `FALSE`: The TiDB Server is capable of commencing service provision immediately after startup, irrespective of the status of the statistics loading.

Configuration Parameter: `performance.lite-init-stats`
- `TRUE`: This setting prevents the loading of any histograms, TopN, or Count-Min Sketch of indexes or columns into memory and is termed lightweight statistics initialization.
- `FALSE`: In this configuration, histograms, TopN, and Count-Min Sketch data for indexes and primary keys are loaded into memory, while such data for non-primary key columns remain unloaded.

Important Notes:
1. For versions preceding v7.2.0, the default value for `performance.force-init-stats` is `false`, whereas it is `true` for v7.2.0 and subsequent versions.
2. Similarly, for `performance.lite-init-stats`, the default is `false` for versions before v7.2.0 and becomes `true` for v7.2.0 and later versions.
3. In scenarios involving a substantial number of tables and partitions, it is advisable to set `performance.force-init-stats` to `false`. Alternatively, configure `performance.force-init-stats` to `true` in combination with `performance.lite-init-stats` set to `true`. Failure to do so will result in extended wait times for TiDB Server during the statistics initialization phase before it can begin providing services.
4. Setting `performance.force-init-stats` to `false` allows the TiDB Server to offer services prior to the completion of statistics initialization. During this period, the output of the `EXPLAIN` command will display the `pseudo` label in the operator info column, signifying the absence of current statistics.