42 lines
1.7 KiB
Markdown
42 lines
1.7 KiB
Markdown
---
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title: Reading RocksDB options from a file
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layout: post
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author: lgalanis
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category: blog
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redirect_from:
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- /blog/1883/reading-rocksdb-options-from-a-file/
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---
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RocksDB options can be provided using a file or any string to RocksDB. The format is straightforward: `write_buffer_size=1024;max_write_buffer_number=2`. Any whitespace around `=` and `;` is OK. Moreover, options can be nested as necessary. For example `BlockBasedTableOptions` can be nested as follows: `write_buffer_size=1024; max_write_buffer_number=2; block_based_table_factory={block_size=4k};`. Similarly any white space around `{` or `}` is ok. Here is what it looks like in code:
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<!--truncate-->
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```c++
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#include <string>
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#include "rocksdb/db.h"
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#include "rocksdb/table.h"
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#include "rocksdb/utilities/convenience.h"
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using namespace rocksdb;
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int main(int argc, char** argv) {
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DB *db;
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Options opt;
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std::string options_string =
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"create_if_missing=true;max_open_files=1000;"
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"block_based_table_factory={block_size=4096}";
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Status s = GetDBOptionsFromString(opt, options_string, &opt);
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s = DB::Open(opt, "/tmp/mydb_rocks", &db);
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// use db
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delete db;
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}
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```
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Using `GetDBOptionsFromString` is a convenient way of changing options for your RocksDB application without needing to resort to recompilation or tedious command line parsing.
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