davidradl commented on code in PR #79:
URL:
https://github.com/apache/flink-connector-jdbc/pull/79#discussion_r1440284858
##########
flink-connector-jdbc/src/main/java/org/apache/flink/connector/jdbc/table/JdbcDynamicTableSource.java:
##########
@@ -96,28 +97,115 @@ public JdbcDynamicTableSource(
public LookupRuntimeProvider getLookupRuntimeProvider(LookupContext
context) {
// JDBC only support non-nested look up keys
String[] keyNames = new String[context.getKeys().length];
+
for (int i = 0; i < keyNames.length; i++) {
int[] innerKeyArr = context.getKeys()[i];
Preconditions.checkArgument(
innerKeyArr.length == 1, "JDBC only support non-nested
look up keys");
keyNames[i] =
DataType.getFieldNames(physicalRowDataType).get(innerKeyArr[0]);
}
+
final RowType rowType = (RowType) physicalRowDataType.getLogicalType();
+
+ String[] conditions = null;
+
+ if (this.resolvedPredicates != null) {
+ conditions = new String[this.resolvedPredicates.size()];
+ int processedPushdownParamsIndex = 0;
+ for (int i = 0; i < this.resolvedPredicates.size(); i++) {
+ String resolvedPredicate = this.resolvedPredicates.get(i);
+
+ /*
+ * This replace seems like it should be using a Flink class to
resolve the parameter. It does not
+ * effect the dialects as the placeholder comes from
JdbcFilterPushdownPreparedStatementVisitor.
+ *
+ * Here is what has been considered as alternatives.
+ *
+ * We cannot use the way this is done in
getScanRuntimeProvider, as the index we have is the index
+ * into the filters, but it needs the index into the fields.
For example one lookup key and one filter
+ * would both have an index of 0, which the subsequent code
would incorrectly resolve to the first
+ * field.
+ * We cannot use the PreparedStatement as we have not got
access to the statement here.
+ * We cannot use ParameterizedPredicate as it takes the filter
expression as input (e.g EQUALS(...)
+ * not the form we have here an example would be ('field1'= ?).
+ *
+ * An entry in the resolvedPredicates list may have more than
one associated pushdown parameter, for example
+ * a query like this : ... on e.type = 2 and (e.age = 50 OR
height > 90) and a.ip = e.ip;
+ * will have 2 resolvedPredicates and 3 pushdownParams. The
2nd and 3rd pushdownParams will be for the second
+ * resolvedPredicate.
+ *
+ */
+ ArrayList<String> paramsForThisPredicate = new ArrayList();
+ char placeholderChar =
+
JdbcFilterPushdownPreparedStatementVisitor.PUSHDOWN_PREDICATE_PLACEHOLDER
+ .charAt(0);
+
+ int count =
+ (int) resolvedPredicate.chars().filter(ch -> ch ==
placeholderChar).count();
+
+ for (int j = processedPushdownParamsIndex;
+ j < processedPushdownParamsIndex + count;
+ j++) {
+
paramsForThisPredicate.add(this.pushdownParams[j].toString());
+ }
+ processedPushdownParamsIndex = processedPushdownParamsIndex +
count;
Review Comment:
I am thinking that I should save the left right and operation in the
visitor. I hope to construct a list of simple binary predicates (each with left
right an operation) connected by any ORs. When this comes through to the
processing where I need to construct the query, I will then know to only do
character replacements in right hand sides (i.e not columns name or column name
expressions). I am investigating whether this is feasible and if so hope to put
something in for review this week.
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