Closed xql923 closed 2 years ago
在这里有配置,可以直接在 fdb_cfg.h 中定义一下
https://github.com/armink/FlashDB/blob/master/src/fdb_kvdb.c#L51
谢谢朱工,请问设置这个数值很大或者很小对数据库的性能有影响吗?
比如我的Nor Flash是W25Q256,一个页Page大小是256Bytes,一个扇区Sector大小是4096Bytes,设置FDB_STR_KV_VALUE_MAX_SIZE为多大最能发挥数据库的效能和Flash的最大性能?
其实这个对性能影响不大,就是会多占用一些内存
我查看了下, 您这个使用栈里面的内存, 我现在想把内存扩大点,500k 我使用了堆里面的内存 rt_malloc 修改了下面这个函数,也不报错了,还是存不进去 , set-kv那里的代码不知道怎么修改
char fdb_kv_get(fdb_kvdb_t db, const char key)
{
//static char value[FDB_STR_KV_VALUE_MAX_SIZE + 1];
char* value=rt_malloc(FDB_STR_KV_VALUE_MAX_SIZE + 1)
size_t get_size;
struct fdb_blob blob;
if ((get_size = fdb_kv_get_blob(db, key, fdb_blob_make(&blob, value, FDB_STR_KV_VALUE_MAX_SIZE))) > 0) {
/* the return value must be string */
//if (fdb_is_str((uint8_t *)value, get_size))
{
value[get_size] = '\0';
return value;
}
}
其实这个对性能影响不大,就是会多占用一些内存 static char kv_kv[10241024] attribute( (at(0xC0F00000)) ); char fdb_kv_get(fdb_kvdb_t db, const char key) { //static char value[FDB_STR_KV_VALUE_MAX_SIZE + 1]; char value=kv_kv; size_t get_size; struct fdb_blob blob;
if ((get_size = fdb_kv_get_blob(db, key, fdb_blob_make(&blob, value, FDB_STR_KV_VALUE_MAX_SIZE))) > 0) {
/* the return value must be string */
if (fdb_is_str((uint8_t *)value, get_size)) {
value[get_size] = '\0';
return value;
} else if (blob.saved.len > FDB_STR_KV_VALUE_MAX_SIZE) {
FDB_INFO("Warning: The default string KV value buffer length (%d) is too less (%zu).\n", FDB_STR_KV_VALUE_MAX_SIZE,
blob.saved.len);
} else {
FDB_INFO("Warning: The KV value isn't string. Could not be returned\n");
return NULL;
}
}
我这样修改下还是不行
不修改任何源码,#define FDB_STR_KV_VALUE_MAX_SIZE 1024*120 取value也取不出来
打印 [FlashDB][kv][env] Warning: The KV value isn't string. Could not be returned [FlashDB][kv][env] Warning: The KV value isn't string. Could not be returned [FlashDB][kv][env] Warning: The KV value isn't string. Could not be returned
朱工你好,请问,对于键值KV型数据库,每个键值支持最大的字符数目是多少?