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NavCache: tolerate BUSY in prepares

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This is obscure, but with multiple copies of FG running, we can
get SQLITE_BUSY when doing prepares as well as during exec/steps.
This commit is contained in:
James Turner 2021-06-18 10:05:42 +01:00
parent bee7b0164f
commit 20e605ca13
1 changed files with 35 additions and 19 deletions
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54
src/Navaids/NavDataCache.cxx
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@ -384,28 +384,45 @@ public:
NavDataCache::DatFileType datFileType,
bool verbose);
void callSqlite(int result, const string& sql)
{
if (result == SQLITE_OK)
return; // all good
sqlite3_stmt_ptr prepareSQL(const std::string& sql)
{
sqlite3_stmt_ptr stmt;
int result = sqlite3_prepare_v2(db, sql.c_str(), sql.length(), &stmt, nullptr);
int retries = 0;
int retryMSec = 1;
while (result == SQLITE_BUSY) {
if (retries > MAX_RETRIES) {
break;
}
++retries;
SGTimeStamp::sleepForMSec(retryMSec);
retryMSec = retryMSec << 1; // double each time
// try again
result = sqlite3_prepare_v2(db, sql.c_str(), sql.length(), &stmt, nullptr);
}
if (result == SQLITE_OK) {
return stmt; // common case, all good
}
string errMsg;
if (result == SQLITE_MISUSE) {
errMsg = "Sqlite API abuse";
SG_LOG(SG_NAVCACHE, SG_ALERT, "Sqlite API abuse");
} else {
errMsg = sqlite3_errmsg(db);
SG_LOG(SG_NAVCACHE, SG_ALERT, "Sqlite error:" << errMsg << " running:\n\t" << sql);
}
string errMsg;
if (result == SQLITE_MISUSE) {
errMsg = "Sqlite API abuse";
SG_LOG(SG_NAVCACHE, SG_ALERT, "Sqlite API abuse");
} else {
errMsg = sqlite3_errmsg(db);
SG_LOG(SG_NAVCACHE, SG_ALERT, "Sqlite error:" << errMsg << " running:\n\t" << sql);
throw sg_exception("Sqlite error:" + errMsg, sql);
}
throw sg_exception("Sqlite error:" + errMsg, sql);
}
void runSQL(const string& sql)
{
sqlite3_stmt_ptr stmt;
callSqlite(sqlite3_prepare_v2(db, sql.c_str(), sql.length(), &stmt, NULL), sql);
sqlite3_stmt_ptr stmt = prepareSQL(sql);
try {
execSelect(stmt);
} catch (sg_exception&) {
@ -418,8 +435,7 @@ public:
sqlite3_stmt_ptr prepare(const string& sql)
{
sqlite3_stmt_ptr stmt;
callSqlite(sqlite3_prepare_v2(db, sql.c_str(), sql.length(), &stmt, NULL), sql);
sqlite3_stmt_ptr stmt = prepareSQL(sql);
prepared.push_back(stmt);
return stmt;
}