in src/Microsoft.Health.Fhir.SqlServer/Features/Search/SqlServerSearchService.cs [186:449]
private async Task<SearchResult> SearchImpl(SqlSearchOptions sqlSearchOptions, SqlSearchType searchType, string currentSearchParameterHash, CancellationToken cancellationToken)
{
Expression searchExpression = sqlSearchOptions.Expression;
// AND in the continuation token
if (!string.IsNullOrWhiteSpace(sqlSearchOptions.ContinuationToken) && !sqlSearchOptions.CountOnly)
{
var continuationToken = ContinuationToken.FromString(sqlSearchOptions.ContinuationToken);
if (continuationToken != null)
{
if (string.IsNullOrEmpty(continuationToken.SortValue))
{
// Check whether it's a _lastUpdated or (_type,_lastUpdated) sort optimization
bool optimize = true;
(SearchParameterInfo searchParamInfo, SortOrder sortOrder) = sqlSearchOptions.Sort.Count == 0 ? default : sqlSearchOptions.Sort[0];
if (sqlSearchOptions.Sort.Count > 0)
{
if (!(searchParamInfo.Name == SearchParameterNames.LastUpdated || searchParamInfo.Name == SearchParameterNames.ResourceType))
{
optimize = false;
}
}
FieldName fieldName;
object keyValue;
SearchParameterInfo parameter;
if (continuationToken.ResourceTypeId == null || _schemaInformation.Current < SchemaVersionConstants.PartitionedTables)
{
// backwards compat
parameter = SqlSearchParameters.ResourceSurrogateIdParameter;
fieldName = SqlFieldName.ResourceSurrogateId;
keyValue = continuationToken.ResourceSurrogateId;
}
else
{
parameter = SqlSearchParameters.PrimaryKeyParameter;
fieldName = SqlFieldName.PrimaryKey;
keyValue = new PrimaryKeyValue(continuationToken.ResourceTypeId.Value, continuationToken.ResourceSurrogateId);
}
Expression lastUpdatedExpression = null;
if (!optimize)
{
lastUpdatedExpression = Expression.GreaterThan(fieldName, null, keyValue);
}
else
{
if (sortOrder == SortOrder.Ascending)
{
lastUpdatedExpression = Expression.GreaterThan(fieldName, null, keyValue);
}
else
{
lastUpdatedExpression = Expression.LessThan(fieldName, null, keyValue);
}
}
var tokenExpression = Expression.SearchParameter(parameter, lastUpdatedExpression);
searchExpression = searchExpression == null ? tokenExpression : Expression.And(tokenExpression, searchExpression);
}
}
else
{
throw new BadRequestException(Resources.InvalidContinuationToken);
}
}
var originalSort = new List<(SearchParameterInfo, SortOrder)>(sqlSearchOptions.Sort);
var clonedSearchOptions = UpdateSort(sqlSearchOptions, searchExpression, searchType);
if (clonedSearchOptions.CountOnly)
{
// if we're only returning a count, discard any _include parameters since included resources are not counted.
searchExpression = searchExpression?.AcceptVisitor(RemoveIncludesRewriter.Instance);
}
SqlRootExpression expression = (SqlRootExpression)searchExpression
?.AcceptVisitor(LastUpdatedToResourceSurrogateIdRewriter.Instance)
.AcceptVisitor(DateTimeEqualityRewriter.Instance)
.AcceptVisitor(FlatteningRewriter.Instance)
.AcceptVisitor(UntypedReferenceRewriter.Instance)
.AcceptVisitor(_sqlRootExpressionRewriter)
.AcceptVisitor(_partitionEliminationRewriter)
.AcceptVisitor(_sortRewriter, clonedSearchOptions)
.AcceptVisitor(SearchParamTableExpressionReorderer.Instance)
.AcceptVisitor(MissingSearchParamVisitor.Instance)
.AcceptVisitor(NotExpressionRewriter.Instance)
.AcceptVisitor(_chainFlatteningRewriter)
.AcceptVisitor(ResourceColumnPredicatePushdownRewriter.Instance)
.AcceptVisitor(DateTimeBoundedRangeRewriter.Instance)
.AcceptVisitor(
(SqlExpressionRewriterWithInitialContext<object>)(_schemaInformation.Current >= SchemaVersionConstants.PartitionedTables
? StringOverflowRewriter.Instance
: LegacyStringOverflowRewriter.Instance))
.AcceptVisitor(NumericRangeRewriter.Instance)
.AcceptVisitor(IncludeMatchSeedRewriter.Instance)
.AcceptVisitor(TopRewriter.Instance, clonedSearchOptions)
.AcceptVisitor(IncludeRewriter.Instance)
?? SqlRootExpression.WithResourceTableExpressions();
using (SqlConnectionWrapper sqlConnectionWrapper = await _sqlConnectionWrapperFactory.ObtainSqlConnectionWrapperAsync(cancellationToken, true))
using (SqlCommandWrapper sqlCommandWrapper = sqlConnectionWrapper.CreateSqlCommand())
{
var stringBuilder = new IndentedStringBuilder(new StringBuilder());
EnableTimeAndIoMessageLogging(stringBuilder, sqlConnectionWrapper);
var queryGenerator = new SqlQueryGenerator(
stringBuilder,
new HashingSqlQueryParameterManager(new SqlQueryParameterManager(sqlCommandWrapper.Parameters)),
_model,
searchType,
_schemaInformation,
currentSearchParameterHash);
expression.AcceptVisitor(queryGenerator, clonedSearchOptions);
sqlCommandWrapper.CommandText = stringBuilder.ToString();
LogSqlCommand(sqlCommandWrapper);
using (var reader = await sqlCommandWrapper.ExecuteReaderAsync(CommandBehavior.SequentialAccess, cancellationToken))
{
if (clonedSearchOptions.CountOnly)
{
await reader.ReadAsync(cancellationToken);
var searchResult = new SearchResult(reader.GetInt32(0), clonedSearchOptions.UnsupportedSearchParams);
// call NextResultAsync to get the info messages
await reader.NextResultAsync(cancellationToken);
return searchResult;
}
var resources = new List<SearchResultEntry>(sqlSearchOptions.MaxItemCount);
short? newContinuationType = null;
long? newContinuationId = null;
bool moreResults = false;
int matchCount = 0;
string sortValue = null;
var isResultPartial = false;
int numberOfColumnsRead = 0;
while (await reader.ReadAsync(cancellationToken))
{
PopulateResourceTableColumnsToRead(
reader,
out short resourceTypeId,
out string resourceId,
out int version,
out bool isDeleted,
out long resourceSurrogateId,
out string requestMethod,
out bool isMatch,
out bool isPartialEntry,
out bool isRawResourceMetaSet,
out string searchParameterHash,
out Stream rawResourceStream);
numberOfColumnsRead = reader.FieldCount;
// If we get to this point, we know there are more results so we need a continuation token
// Additionally, this resource shouldn't be included in the results
if (matchCount >= clonedSearchOptions.MaxItemCount && isMatch)
{
moreResults = true;
continue;
}
string rawResource;
using (rawResourceStream)
{
rawResource = await _compressedRawResourceConverter.ReadCompressedRawResource(rawResourceStream);
}
// See if this resource is a continuation token candidate and increase the count
if (isMatch)
{
newContinuationType = resourceTypeId;
newContinuationId = resourceSurrogateId;
// For normal queries, we select _defaultNumberOfColumnsReadFromResult number of columns.
// If we have more, that means we have an extra column tracking sort value.
// Keep track of sort value if this is the last row.
if (matchCount == clonedSearchOptions.MaxItemCount - 1 && reader.FieldCount > _defaultNumberOfColumnsReadFromResult)
{
var tempSortValue = reader.GetValue(SortValueColumnName);
if ((tempSortValue as DateTime?) != null)
{
sortValue = (tempSortValue as DateTime?).Value.ToString("o");
}
else
{
sortValue = tempSortValue.ToString();
}
}
matchCount++;
}
// as long as at least one entry was marked as partial, this resultset
// should be marked as partial
isResultPartial = isResultPartial || isPartialEntry;
resources.Add(new SearchResultEntry(
new ResourceWrapper(
resourceId,
version.ToString(CultureInfo.InvariantCulture),
_model.GetResourceTypeName(resourceTypeId),
new RawResource(rawResource, FhirResourceFormat.Json, isMetaSet: isRawResourceMetaSet),
new ResourceRequest(requestMethod),
new DateTimeOffset(ResourceSurrogateIdHelper.ResourceSurrogateIdToLastUpdated(resourceSurrogateId), TimeSpan.Zero),
isDeleted,
null,
null,
null,
searchParameterHash),
isMatch ? SearchEntryMode.Match : SearchEntryMode.Include));
}
// call NextResultAsync to get the info messages
await reader.NextResultAsync(cancellationToken);
ContinuationToken continuationToken =
moreResults
? new ContinuationToken(
clonedSearchOptions.Sort.Select(s =>
s.searchParameterInfo.Name switch
{
SearchParameterNames.ResourceType => (object)newContinuationType,
SearchParameterNames.LastUpdated => newContinuationId,
_ => sortValue,
}).ToArray())
: null;
if (isResultPartial)
{
_requestContextAccessor.RequestContext.BundleIssues.Add(
new OperationOutcomeIssue(
OperationOutcomeConstants.IssueSeverity.Warning,
OperationOutcomeConstants.IssueType.Incomplete,
Core.Resources.TruncatedIncludeMessage));
}
// If this is a sort query, lets keep track of whether we actually searched for sort values.
if (clonedSearchOptions.Sort != null &&
clonedSearchOptions.Sort.Count > 0 &&
clonedSearchOptions.Sort[0].searchParameterInfo.Code != KnownQueryParameterNames.LastUpdated)
{
sqlSearchOptions.DidWeSearchForSortValue = numberOfColumnsRead > _defaultNumberOfColumnsReadFromResult;
}
// This value is set inside the SortRewriter. If it is set, we need to pass
// this value back to the caller.
if (clonedSearchOptions.IsSortWithFilter)
{
sqlSearchOptions.IsSortWithFilter = true;
}
return new SearchResult(resources, continuationToken?.ToJson(), originalSort, clonedSearchOptions.UnsupportedSearchParams);
}
}
}