diff options
Diffstat (limited to 'vendor/github.com/jackc/pgx/v5/internal/stmtcache')
3 files changed, 226 insertions, 0 deletions
diff --git a/vendor/github.com/jackc/pgx/v5/internal/stmtcache/lru_cache.go b/vendor/github.com/jackc/pgx/v5/internal/stmtcache/lru_cache.go new file mode 100644 index 000000000..a25cc8b1c --- /dev/null +++ b/vendor/github.com/jackc/pgx/v5/internal/stmtcache/lru_cache.go @@ -0,0 +1,98 @@ +package stmtcache + +import ( + "container/list" + + "github.com/jackc/pgx/v5/pgconn" +) + +// LRUCache implements Cache with a Least Recently Used (LRU) cache. +type LRUCache struct { + cap int + m map[string]*list.Element + l *list.List + invalidStmts []*pgconn.StatementDescription +} + +// NewLRUCache creates a new LRUCache. cap is the maximum size of the cache. +func NewLRUCache(cap int) *LRUCache { + return &LRUCache{ + cap: cap, + m: make(map[string]*list.Element), + l: list.New(), + } +} + +// Get returns the statement description for sql. Returns nil if not found. +func (c *LRUCache) Get(key string) *pgconn.StatementDescription { + if el, ok := c.m[key]; ok { + c.l.MoveToFront(el) + return el.Value.(*pgconn.StatementDescription) + } + + return nil + +} + +// Put stores sd in the cache. Put panics if sd.SQL is "". Put does nothing if sd.SQL already exists in the cache. +func (c *LRUCache) Put(sd *pgconn.StatementDescription) { + if sd.SQL == "" { + panic("cannot store statement description with empty SQL") + } + + if _, present := c.m[sd.SQL]; present { + return + } + + if c.l.Len() == c.cap { + c.invalidateOldest() + } + + el := c.l.PushFront(sd) + c.m[sd.SQL] = el +} + +// Invalidate invalidates statement description identified by sql. Does nothing if not found. +func (c *LRUCache) Invalidate(sql string) { + if el, ok := c.m[sql]; ok { + delete(c.m, sql) + c.invalidStmts = append(c.invalidStmts, el.Value.(*pgconn.StatementDescription)) + c.l.Remove(el) + } +} + +// InvalidateAll invalidates all statement descriptions. +func (c *LRUCache) InvalidateAll() { + el := c.l.Front() + for el != nil { + c.invalidStmts = append(c.invalidStmts, el.Value.(*pgconn.StatementDescription)) + el = el.Next() + } + + c.m = make(map[string]*list.Element) + c.l = list.New() +} + +func (c *LRUCache) HandleInvalidated() []*pgconn.StatementDescription { + invalidStmts := c.invalidStmts + c.invalidStmts = nil + return invalidStmts +} + +// Len returns the number of cached prepared statement descriptions. +func (c *LRUCache) Len() int { + return c.l.Len() +} + +// Cap returns the maximum number of cached prepared statement descriptions. +func (c *LRUCache) Cap() int { + return c.cap +} + +func (c *LRUCache) invalidateOldest() { + oldest := c.l.Back() + sd := oldest.Value.(*pgconn.StatementDescription) + c.invalidStmts = append(c.invalidStmts, sd) + delete(c.m, sd.SQL) + c.l.Remove(oldest) +} diff --git a/vendor/github.com/jackc/pgx/v5/internal/stmtcache/stmtcache.go b/vendor/github.com/jackc/pgx/v5/internal/stmtcache/stmtcache.go new file mode 100644 index 000000000..e1bdcba57 --- /dev/null +++ b/vendor/github.com/jackc/pgx/v5/internal/stmtcache/stmtcache.go @@ -0,0 +1,57 @@ +// Package stmtcache is a cache for statement descriptions. +package stmtcache + +import ( + "strconv" + "sync/atomic" + + "github.com/jackc/pgx/v5/pgconn" +) + +var stmtCounter int64 + +// NextStatementName returns a statement name that will be unique for the lifetime of the program. +func NextStatementName() string { + n := atomic.AddInt64(&stmtCounter, 1) + return "stmtcache_" + strconv.FormatInt(n, 10) +} + +// Cache caches statement descriptions. +type Cache interface { + // Get returns the statement description for sql. Returns nil if not found. + Get(sql string) *pgconn.StatementDescription + + // Put stores sd in the cache. Put panics if sd.SQL is "". Put does nothing if sd.SQL already exists in the cache. + Put(sd *pgconn.StatementDescription) + + // Invalidate invalidates statement description identified by sql. Does nothing if not found. + Invalidate(sql string) + + // InvalidateAll invalidates all statement descriptions. + InvalidateAll() + + // HandleInvalidated returns a slice of all statement descriptions invalidated since the last call to HandleInvalidated. + HandleInvalidated() []*pgconn.StatementDescription + + // Len returns the number of cached prepared statement descriptions. + Len() int + + // Cap returns the maximum number of cached prepared statement descriptions. + Cap() int +} + +func IsStatementInvalid(err error) bool { + pgErr, ok := err.(*pgconn.PgError) + if !ok { + return false + } + + // https://github.com/jackc/pgx/issues/1162 + // + // We used to look for the message "cached plan must not change result type". However, that message can be localized. + // Unfortunately, error code "0A000" - "FEATURE NOT SUPPORTED" is used for many different errors and the only way to + // tell the difference is by the message. But all that happens is we clear a statement that we otherwise wouldn't + // have so it should be safe. + possibleInvalidCachedPlanError := pgErr.Code == "0A000" + return possibleInvalidCachedPlanError +} diff --git a/vendor/github.com/jackc/pgx/v5/internal/stmtcache/unlimited_cache.go b/vendor/github.com/jackc/pgx/v5/internal/stmtcache/unlimited_cache.go new file mode 100644 index 000000000..f5f59396e --- /dev/null +++ b/vendor/github.com/jackc/pgx/v5/internal/stmtcache/unlimited_cache.go @@ -0,0 +1,71 @@ +package stmtcache + +import ( + "math" + + "github.com/jackc/pgx/v5/pgconn" +) + +// UnlimitedCache implements Cache with no capacity limit. +type UnlimitedCache struct { + m map[string]*pgconn.StatementDescription + invalidStmts []*pgconn.StatementDescription +} + +// NewUnlimitedCache creates a new UnlimitedCache. +func NewUnlimitedCache() *UnlimitedCache { + return &UnlimitedCache{ + m: make(map[string]*pgconn.StatementDescription), + } +} + +// Get returns the statement description for sql. Returns nil if not found. +func (c *UnlimitedCache) Get(sql string) *pgconn.StatementDescription { + return c.m[sql] +} + +// Put stores sd in the cache. Put panics if sd.SQL is "". Put does nothing if sd.SQL already exists in the cache. +func (c *UnlimitedCache) Put(sd *pgconn.StatementDescription) { + if sd.SQL == "" { + panic("cannot store statement description with empty SQL") + } + + if _, present := c.m[sd.SQL]; present { + return + } + + c.m[sd.SQL] = sd +} + +// Invalidate invalidates statement description identified by sql. Does nothing if not found. +func (c *UnlimitedCache) Invalidate(sql string) { + if sd, ok := c.m[sql]; ok { + delete(c.m, sql) + c.invalidStmts = append(c.invalidStmts, sd) + } +} + +// InvalidateAll invalidates all statement descriptions. +func (c *UnlimitedCache) InvalidateAll() { + for _, sd := range c.m { + c.invalidStmts = append(c.invalidStmts, sd) + } + + c.m = make(map[string]*pgconn.StatementDescription) +} + +func (c *UnlimitedCache) HandleInvalidated() []*pgconn.StatementDescription { + invalidStmts := c.invalidStmts + c.invalidStmts = nil + return invalidStmts +} + +// Len returns the number of cached prepared statement descriptions. +func (c *UnlimitedCache) Len() int { + return len(c.m) +} + +// Cap returns the maximum number of cached prepared statement descriptions. +func (c *UnlimitedCache) Cap() int { + return math.MaxInt +} |