sql: add parseHint step when loading hint into hints cache

When loading an external statement hint into the statement hints cache,
we might need to call some function to get the hint ready for use. (For
hint injections, this function is `tree.NewHintInjectionDonor` which
parses and walks the donor statement fingerprint.) This function could
fail, in which case we want to skip over the hint but not return an
error from `GetStatementHintsFromDB`. This function could succeed but
create some extra state which we need to save.

This commit adds a new `parseHint` step which calls any functions needed
to get the hint ready, and creates a new `hints.Hint` struct which holds
the object(s) created when parsing hints. (These are analogous to
`parseStats` and `TableStatistic` from the stats cache.)

Informs: #153633

Release note: None

Author: michae2

pkg/sql/hints/BUILD.bazel

@@ -24,12 +24,14 @@ go_library(
         "//pkg/sql/catalog/systemschema",
         "//pkg/sql/hintpb",
         "//pkg/sql/isql",
+        "//pkg/sql/parserutils",
         "//pkg/sql/rowenc",
         "//pkg/sql/sem/tree",
         "//pkg/sql/sessiondata",
         "//pkg/sql/types",
         "//pkg/util/buildutil",
         "//pkg/util/cache",
+        "//pkg/util/errorutil",
         "//pkg/util/hlc",
         "//pkg/util/log",
         "//pkg/util/metamorphic",
@@ -59,11 +61,14 @@ go_test(
         "//pkg/security/securityassets",
         "//pkg/security/securitytest",
         "//pkg/server",
+        "//pkg/settings/cluster",
         "//pkg/sql",
         "//pkg/sql/catalog/descs",
         "//pkg/sql/hintpb",
         "//pkg/sql/isql",
+        "//pkg/sql/parserutils",
         "//pkg/sql/randgen",
+        "//pkg/sql/sem/tree",
         "//pkg/sql/stats",
         "//pkg/storage/fs",
         "//pkg/testutils",

pkg/sql/hints/hint_cache.go

@@ -25,7 +25,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/descpb"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/descs"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/systemschema"
-	"github.com/cockroachdb/cockroach/pkg/sql/hintpb"
 	"github.com/cockroachdb/cockroach/pkg/sql/rowenc"
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 	"github.com/cockroachdb/cockroach/pkg/sql/types"
@@ -406,8 +405,8 @@ func (c *StatementHintsCache) GetGeneration() int64 {
 // plans). It returns nil if the statement has no hints, or there was an error
 // retrieving them.
 func (c *StatementHintsCache) MaybeGetStatementHints(
-	ctx context.Context, statementFingerprint string,
-) (hints []hintpb.StatementHintUnion, ids []int64) {
+	ctx context.Context, statementFingerprint string, fingerprintFlags tree.FmtFlags,
+) (hints []Hint, ids []int64) {
 	hash := fnv.New64()
 	_, err := hash.Write([]byte(statementFingerprint))
 	if err != nil {
@@ -430,7 +429,7 @@ func (c *StatementHintsCache) MaybeGetStatementHints(
 	if !ok {
 		// The plan hints were evicted from the cache. Retrieve them from the
 		// database and add them to the cache.
-		return c.addCacheEntryLocked(ctx, statementHash, statementFingerprint)
+		return c.addCacheEntryLocked(ctx, statementHash, statementFingerprint, fingerprintFlags)
 	}
 	entry := e.(*cacheEntry)
 	c.maybeWaitForRefreshLocked(ctx, entry, statementHash)
@@ -464,8 +463,11 @@ func (c *StatementHintsCache) maybeWaitForRefreshLocked(
 // other queries to wait for the result via sync.Cond. Note that the lock is
 // released while reading from the db, and then reacquired.
 func (c *StatementHintsCache) addCacheEntryLocked(
-	ctx context.Context, statementHash int64, statementFingerprint string,
-) (hints []hintpb.StatementHintUnion, ids []int64) {
+	ctx context.Context,
+	statementHash int64,
+	statementFingerprint string,
+	fingerprintFlags tree.FmtFlags,
+) (hints []Hint, ids []int64) {
 	c.mu.AssertHeld()
 
 	// Add a cache entry that other queries can find and wait on until we have the
@@ -483,7 +485,7 @@ func (c *StatementHintsCache) addCacheEntryLocked(
 		defer c.mu.Lock()
 		log.VEventf(ctx, 1, "reading hints for query %s", statementFingerprint)
 		entry.ids, entry.fingerprints, entry.hints, err =
-			GetStatementHintsFromDB(ctx, c.db.Executor(), statementHash)
+			GetStatementHintsFromDB(ctx, c.db.Executor(), statementHash, fingerprintFlags)
 		log.VEventf(ctx, 1, "finished reading hints for query %s", statementFingerprint)
 	}()
 
@@ -517,16 +519,14 @@ type cacheEntry struct {
 	// be duplicate entries in the fingerprints slice.
 	// TODO(drewk): consider de-duplicating the fingerprint strings to reduce
 	// memory usage.
-	hints        []hintpb.StatementHintUnion
+	hints        []Hint
 	fingerprints []string
 	ids          []int64
 }
 
 // getMatchingHints returns the plan hints and row IDs for the given
 // fingerprint, or nil if they don't exist. The results are in order of row ID.
-func (entry *cacheEntry) getMatchingHints(
-	statementFingerprint string,
-) (hints []hintpb.StatementHintUnion, ids []int64) {
+func (entry *cacheEntry) getMatchingHints(statementFingerprint string) (hints []Hint, ids []int64) {
 	for i := range entry.hints {
 		if entry.fingerprints[i] == statementFingerprint {
 			hints = append(hints, entry.hints[i])