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+/*
+ * Uses a two-level B-tree to store a set of key-value pairs.
+ *
+ * September 2, 2012
+ * Eleanor Cawthon
+ * eleanor.cawthon@inktank.com
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation. See file COPYING.
+ */
+
+#ifndef KVFLATBTREEASYNC_H_
+#define KVFLATBTREEASYNC_H_
+
+#define ESUICIDE 134
+#define EPREFIX 136
+#define EFIRSTOBJ 138
+
+#include "key_value_store/key_value_structure.h"
+#include "include/utime.h"
+#include "include/types.h"
+#include "include/encoding.h"
+#include "common/ceph_mutex.h"
+#include "common/Clock.h"
+#include "common/Formatter.h"
+#include "global/global_context.h"
+#include "include/rados/librados.hpp"
+#include <cfloat>
+#include <queue>
+#include <sstream>
+#include <stdarg.h>
+
+using ceph::bufferlist;
+
+
+enum {
+ ADD_PREFIX = 1,
+ MAKE_OBJECT = 2,
+ UNWRITE_OBJECT = 3,
+ RESTORE_OBJECT = 4,
+ REMOVE_OBJECT = 5,
+ REMOVE_PREFIX = 6,
+ AIO_MAKE_OBJECT = 7
+};
+
+struct rebalance_args;
+
+/**
+ * stores information about a key in the index.
+ *
+ * prefix is "0" unless key is "", in which case it is "1". This ensures that
+ * the object with key "" will always be the highest key in the index.
+ */
+struct key_data {
+ std::string raw_key;
+ std::string prefix;
+
+ key_data()
+ {}
+
+ /**
+ * @pre: key is a raw key (does not contain a prefix)
+ */
+ key_data(std::string key)
+ : raw_key(key)
+ {
+ raw_key == "" ? prefix = "1" : prefix = "0";
+ }
+
+ bool operator==(key_data k) const {
+ return ((raw_key == k.raw_key) && (prefix == k.prefix));
+ }
+
+ bool operator!=(key_data k) const {
+ return ((raw_key != k.raw_key) || (prefix != k.prefix));
+ }
+
+ bool operator<(key_data k) const {
+ return this->encoded() < k.encoded();
+ }
+
+ bool operator>(key_data k) const {
+ return this->encoded() > k.encoded();
+ }
+
+ /**
+ * parses the prefix from encoded and stores the data in this.
+ *
+ * @pre: encoded has a prefix
+ */
+ void parse(std::string encoded) {
+ prefix = encoded[0];
+ raw_key = encoded.substr(1,encoded.length());
+ }
+
+ /**
+ * returns a string containing the encoded (prefixed) key
+ */
+ std::string encoded() const {
+ return prefix + raw_key;
+ }
+
+ void encode(bufferlist &bl) const {
+ ENCODE_START(1,1,bl);
+ encode(raw_key, bl);
+ encode(prefix, bl);
+ ENCODE_FINISH(bl);
+ }
+ void decode(bufferlist::const_iterator &p) {
+ DECODE_START(1, p);
+ decode(raw_key, p);
+ decode(prefix, p);
+ DECODE_FINISH(p);
+ }
+};
+WRITE_CLASS_ENCODER(key_data)
+
+
+/**
+ * Stores information read from a librados object.
+ */
+struct object_data {
+ key_data min_kdata; //the max key from the previous index entry
+ key_data max_kdata; //the max key, from the index
+ std::string name; //the object's name
+ std::map<std::string, bufferlist> omap; // the omap of the object
+ bool unwritable; // an xattr that, if false, means an op is in
+ // progress and other clients should not write to it.
+ uint64_t version; //the version at time of read
+ uint64_t size; //the number of elements in the omap
+
+ object_data()
+ : unwritable(false),
+ version(0),
+ size(0)
+ {}
+
+ object_data(std::string the_name)
+ : name(the_name),
+ unwritable(false),
+ version(0),
+ size(0)
+ {}
+
+ object_data(key_data min, key_data kdat, std::string the_name)
+ : min_kdata(min),
+ max_kdata(kdat),
+ name(the_name),
+ unwritable(false),
+ version(0),
+ size(0)
+ {}
+
+ object_data(key_data min, key_data kdat, std::string the_name,
+ std::map<std::string, bufferlist> the_omap)
+ : min_kdata(min),
+ max_kdata(kdat),
+ name(the_name),
+ omap(the_omap),
+ unwritable(false),
+ version(0),
+ size(0)
+ {}
+
+ object_data(key_data min, key_data kdat, std::string the_name, int the_version)
+ : min_kdata(min),
+ max_kdata(kdat),
+ name(the_name),
+ unwritable(false),
+ version(the_version),
+ size(0)
+ {}
+
+ void encode(bufferlist &bl) const {
+ ENCODE_START(1,1,bl);
+ encode(min_kdata, bl);
+ encode(max_kdata, bl);
+ encode(name, bl);
+ encode(omap, bl);
+ encode(unwritable, bl);
+ encode(version, bl);
+ encode(size, bl);
+ ENCODE_FINISH(bl);
+ }
+ void decode(bufferlist::const_iterator &p) {
+ DECODE_START(1, p);
+ decode(min_kdata, p);
+ decode(max_kdata, p);
+ decode(name, p);
+ decode(omap, p);
+ decode(unwritable, p);
+ decode(version, p);
+ decode(size, p);
+ DECODE_FINISH(p);
+ }
+};
+WRITE_CLASS_ENCODER(object_data)
+
+/**
+ * information about objects to be created by a split or merge - stored in the
+ * index_data.
+ */
+struct create_data {
+ key_data min;
+ key_data max;
+ std::string obj;
+
+ create_data()
+ {}
+
+ create_data(key_data n, key_data x, std::string o)
+ : min(n),
+ max(x),
+ obj(o)
+ {}
+
+ create_data(object_data o)
+ : min(o.min_kdata),
+ max(o.max_kdata),
+ obj(o.name)
+ {}
+
+ create_data & operator=(const create_data &c) {
+ min = c.min;
+ max = c.max;
+ obj = c.obj;
+ return *this;
+ }
+
+ void encode(bufferlist &bl) const {
+ ENCODE_START(1,1,bl);
+ encode(min, bl);
+ encode(max, bl);
+ encode(obj, bl);
+ ENCODE_FINISH(bl);
+ }
+ void decode(bufferlist::const_iterator &p) {
+ DECODE_START(1, p);
+ decode(min, p);
+ decode(max, p);
+ decode(obj, p);
+ DECODE_FINISH(p);
+ }
+};
+WRITE_CLASS_ENCODER(create_data)
+
+/**
+ * information about objects to be deleted by a split or merge - stored in the
+ * index_data.
+ */
+struct delete_data {
+ key_data min;
+ key_data max;
+ std::string obj;
+ uint64_t version;
+
+ delete_data()
+ : version(0)
+ {}
+
+ delete_data(key_data n, key_data x, std::string o, uint64_t v)
+ : min(n),
+ max(x),
+ obj(o),
+ version(v)
+ {}
+
+ delete_data & operator=(const delete_data &d) {
+ min = d.min;
+ max = d.max;
+ obj = d.obj;
+ version = d.version;
+ return *this;
+ }
+
+
+ void encode(bufferlist &bl) const {
+ ENCODE_START(1,1,bl);
+ encode(min, bl);
+ encode(max, bl);
+ encode(obj, bl);
+ encode(version, bl);
+ ENCODE_FINISH(bl);
+ }
+ void decode(bufferlist::const_iterator &p) {
+ DECODE_START(1, p);
+ decode(min, p);
+ decode(max, p);
+ decode(obj, p);
+ decode(version, p);
+ DECODE_FINISH(p);
+ }
+};
+WRITE_CLASS_ENCODER(delete_data)
+
+/**
+ * The index object is a key value map that stores
+ * the highest key stored in an object as keys, and an index_data
+ * as the corresponding value. The index_data contains the encoded
+ * high and low keys (where keys in this object are > min_kdata and
+ * <= kdata), the name of the librados object where keys containing
+ * that range of keys are located, and information about split and
+ * merge operations that may need to be cleaned up if a client dies.
+ */
+struct index_data {
+ //the encoded key corresponding to the object
+ key_data kdata;
+
+ //"1" if there is a prefix (because a split or merge is
+ //in progress), otherwise ""
+ std::string prefix;
+
+ //the kdata of the previous index entry
+ key_data min_kdata;
+
+ utime_t ts; //time that a split/merge started
+
+ //objects to be created
+ std::vector<create_data > to_create;
+
+ //objects to be deleted
+ std::vector<delete_data > to_delete;
+
+ //the name of the object where the key range is located.
+ std::string obj;
+
+ index_data()
+ {}
+
+ index_data(std::string raw_key)
+ : kdata(raw_key)
+ {}
+
+ index_data(key_data max, key_data min, std::string o)
+ : kdata(max),
+ min_kdata(min),
+ obj(o)
+ {}
+
+ index_data(create_data c)
+ : kdata(c.max),
+ min_kdata(c.min),
+ obj(c.obj)
+ {}
+
+ bool operator<(const index_data &other) const {
+ return (kdata.encoded() < other.kdata.encoded());
+ }
+
+ //true if there is a prefix and now - ts > timeout.
+ bool is_timed_out(utime_t now, utime_t timeout) const;
+
+ void encode(bufferlist &bl) const {
+ ENCODE_START(1,1,bl);
+ encode(prefix, bl);
+ encode(min_kdata, bl);
+ encode(kdata, bl);
+ encode(ts, bl);
+ encode(to_create, bl);
+ encode(to_delete, bl);
+ encode(obj, bl);
+ ENCODE_FINISH(bl);
+ }
+ void decode(bufferlist::const_iterator &p) {
+ DECODE_START(1, p);
+ decode(prefix, p);
+ decode(min_kdata, p);
+ decode(kdata, p);
+ decode(ts, p);
+ decode(to_create, p);
+ decode(to_delete, p);
+ decode(obj, p);
+ DECODE_FINISH(p);
+ }
+
+ /*
+ * Prints a string representation of the information, in the following format:
+ * (min_kdata/
+ * kdata,
+ * prefix
+ * ts
+ * elements of to_create, organized into (high key| obj name)
+ * ;
+ * elements of to_delete, organized into (high key| obj name | version number)
+ * :
+ * val)
+ */
+ std::string str() const {
+ std::stringstream strm;
+ strm << '(' << min_kdata.encoded() << "/" << kdata.encoded() << ','
+ << prefix;
+ if (prefix == "1") {
+ strm << ts.sec() << '.' << ts.usec();
+ for(std::vector<create_data>::const_iterator it = to_create.begin();
+ it != to_create.end(); ++it) {
+ strm << '(' << it->min.encoded() << '/' << it->max.encoded() << '|'
+ << it->obj << ')';
+ }
+ strm << ';';
+ for(std::vector<delete_data >::const_iterator it = to_delete.begin();
+ it != to_delete.end(); ++it) {
+ strm << '(' << it->min.encoded() << '/' << it->max.encoded() << '|'
+ << it->obj << '|'
+ << it->version << ')';
+ }
+ strm << ':';
+ }
+ strm << obj << ')';
+ return strm.str();
+ }
+};
+WRITE_CLASS_ENCODER(index_data)
+
+/**
+ * Structure to store information read from the index for reuse.
+ */
+class IndexCache {
+protected:
+ std::map<key_data, std::pair<index_data, utime_t> > k2itmap;
+ std::map<utime_t, key_data> t2kmap;
+ int cache_size;
+
+public:
+ IndexCache(int n)
+ : cache_size(n)
+ {}
+ /**
+ * Inserts idata into the cache and removes whatever key mapped to before.
+ * If the cache is full, pops the oldest entry.
+ */
+ void push(const std::string &key, const index_data &idata);
+
+ /**
+ * Inserts idata into the cache. If idata.kdata is already in the cache,
+ * replaces the old one. Pops the oldest entry if the cache is full.
+ */
+ void push(const index_data &idata);
+
+ /**
+ * Removes the oldest entry from the cache
+ */
+ void pop();
+
+ /**
+ * Removes the value associated with kdata from both maps
+ */
+ void erase(key_data kdata);
+
+ /**
+ * gets the idata where key belongs. If none, returns -ENODATA.
+ */
+ int get(const std::string &key, index_data *idata) const;
+
+ /**
+ * Gets the idata where key goes and the one after it. If there are not
+ * valid entries for both of them, returns -ENODATA.
+ */
+ int get(const std::string &key, index_data *idata, index_data * next_idata) const;
+ void clear();
+};
+
+class KvFlatBtreeAsync;
+
+
+/**
+ * These are used internally to translate aio operations into useful thread
+ * arguments.
+ */
+struct aio_set_args {
+ KvFlatBtreeAsync * kvba;
+ std::string key;
+ bufferlist val;
+ bool exc;
+ callback cb;
+ void * cb_args;
+ int * err;
+};
+
+struct aio_rm_args {
+ KvFlatBtreeAsync * kvba;
+ std::string key;
+ callback cb;
+ void * cb_args;
+ int * err;
+};
+
+struct aio_get_args {
+ KvFlatBtreeAsync * kvba;
+ std::string key;
+ bufferlist * val;
+ bool exc;
+ callback cb;
+ void * cb_args;
+ int * err;
+};
+
+class KvFlatBtreeAsync : public KeyValueStructure {
+protected:
+
+ //don't change these once operations start being called - they are not
+ //protected with mutexes!
+ int k;
+ std::string index_name;
+ librados::IoCtx io_ctx;
+ std::string rados_id;
+ std::string client_name;
+ librados::Rados rados;
+ std::string pool_name;
+ injection_t interrupt;
+ int wait_ms;
+ utime_t timeout; //declare a client dead if it goes this long without
+ //finishing a split/merge
+ int cache_size;
+ double cache_refresh; //read cache_size / cache_refresh entries each time the
+ //index is read
+ bool verbose;//if true, display lots of debug output
+
+ //shared variables protected with mutexes
+ ceph::mutex client_index_lock = ceph::make_mutex("client_index_lock");
+ int client_index; //names of new objects are client_name.client_index
+ ceph::mutex icache_lock = ceph::make_mutex("icache_lock");
+ IndexCache icache;
+ friend struct index_data;
+
+ /**
+ * finds the object in the index with the lowest key value that is greater
+ * than idata.kdata. If idata.kdata is the max key, returns -EOVERFLOW. If
+ * idata has a prefix and has timed out, cleans up.
+ *
+ * @param idata: idata for the object to search for.
+ * @param out_data: the idata for the next object.
+ *
+ * @pre: idata must contain a key_data.
+ * @post: out_data contains complete information
+ */
+ int next(const index_data &idata, index_data * out_data);
+
+ /**
+ * finds the object in the index with the lowest key value that is greater
+ * than idata.kdata. If idata.kdata is the lowest key, returns -ERANGE If
+ * idata has a prefix and has timed out, cleans up.
+ *
+ * @param idata: idata for the object to search for.
+ * @param out_data: the idata for the next object.
+ *
+ * @pre: idata must contain a key_data.
+ * @post: out_data contains complete information
+ */
+ int prev(const index_data &idata, index_data * out_data);
+
+ /**
+ * finds the index_data where a key belongs, from cache if possible. If it
+ * reads the index object, it will read the first cache_size entries after
+ * key and put them in the cache.
+ *
+ * @param key: the key to search for
+ * @param idata: the index_data for the first index value such that idata.key
+ * is greater than key.
+ * @param next_idata: if not NULL, this will be set to the idata after idata
+ * @param force_update: if false, will try to read from cache first.
+ *
+ * @pre: key is not encoded
+ * @post: idata contains complete information
+ * stored
+ */
+ int read_index(const std::string &key, index_data * idata,
+ index_data * next_idata, bool force_update);
+
+ /**
+ * Reads obj and generates information about it. Iff the object has >= 2k
+ * entries, reads the whole omap and then splits it.
+ *
+ * @param idata: index data for the object being split
+ * @pre: idata contains a key and an obj
+ * @post: idata.obj has been split and icache has been updated
+ * @return -EBALANCE if obj does not need to be split, 0 if split successful,
+ * error from read_object or perform_ops if there is one.
+ */
+ int split(const index_data &idata);
+
+ /**
+ * reads o1 and the next object after o1 and, if necessary, rebalances them.
+ * if hk1 is the highest key in the index, calls rebalance on the next highest
+ * key.
+ *
+ * @param idata: index data for the object being rebalanced
+ * @param next_idata: index data for the next object. If blank, will read.
+ * @pre: idata contains a key and an obj
+ * @post: idata.obj has been rebalanced and icache has been updated
+ * @return -EBALANCE if no change needed, -ENOENT if o1 does not exist,
+ * -ECANCELED if second object does not exist, otherwise, error from
+ * perform_ops
+ */
+ int rebalance(const index_data &idata1, const index_data &next_idata);
+
+ /**
+ * performs an ObjectReadOperation to populate odata
+ *
+ * @post: odata has all information about obj except for key (which is "")
+ */
+ int read_object(const std::string &obj, object_data * odata);
+
+ /**
+ * performs a maybe_read_for_balance ObjectOperation so the omap is only
+ * read if the object is out of bounds.
+ */
+ int read_object(const std::string &obj, rebalance_args * args);
+
+ /**
+ * sets up owo to change the index in preparation for a split/merge.
+ *
+ * @param to_create: vector of object_data to be created.
+ * @param to_delete: vector of object_data to be deleted.
+ * @param owo: the ObjectWriteOperation to set up
+ * @param idata: will be populated by index data for this op.
+ * @param err: error code reference to pass to omap_cmp
+ * @pre: entries in to_create and to_delete must have keys and names.
+ */
+ void set_up_prefix_index(
+ const std::vector<object_data> &to_create,
+ const std::vector<object_data> &to_delete,
+ librados::ObjectWriteOperation * owo,
+ index_data * idata,
+ int * err);
+
+ /**
+ * sets up all make, mark, restore, and delete ops, as well as the remove
+ * prefix op, based on idata.
+ *
+ * @param create_vector: vector of data about the objects to be created.
+ * @pre: entries in create_data must have names and omaps and be in idata
+ * order
+ * @param delete_vector: vector of data about the objects to be deleted
+ * @pre: entries in to_delete must have versions and be in idata order
+ * @param ops: the owos to set up. the pair is a pair of op identifiers
+ * and names of objects - set_up_ops fills these in.
+ * @pre: ops must be the correct size and the ObjectWriteOperation pointers
+ * must be valid.
+ * @param idata: the idata with information about how to set up the ops
+ * @pre: idata has valid to_create and to_delete
+ * @param err: the int to get the error value for omap_cmp
+ */
+ void set_up_ops(
+ const std::vector<object_data> &create_vector,
+ const std::vector<object_data> &delete_vector,
+ std::vector<std::pair<std::pair<int, std::string>, librados::ObjectWriteOperation*> > * ops,
+ const index_data &idata,
+ int * err);
+
+ /**
+ * sets up owo to exclusive create, set omap to to_set, and set
+ * unwritable to "0"
+ */
+ void set_up_make_object(
+ const std::map<std::string, bufferlist> &to_set,
+ librados::ObjectWriteOperation *owo);
+
+ /**
+ * sets up owo to assert object version and that object version is
+ * writable,
+ * then mark it unwritable.
+ *
+ * @param ver: if this is 0, no version is asserted.
+ */
+ void set_up_unwrite_object(
+ const int &ver, librados::ObjectWriteOperation *owo);
+
+ /**
+ * sets up owo to assert that an object is unwritable and then mark it
+ * writable
+ */
+ void set_up_restore_object(
+ librados::ObjectWriteOperation *owo);
+
+ /**
+ * sets up owo to assert that the object is unwritable and then remove it
+ */
+ void set_up_delete_object(
+ librados::ObjectWriteOperation *owo);
+
+ /**
+ * perform the operations in ops and handles errors.
+ *
+ * @param debug_prefix: what to print at the beginning of debug output
+ * @param idata: the idata for the object being operated on, to be
+ * passed to cleanup if necessary
+ * @param ops: this contains an int identifying the type of op,
+ * a string that is the name of the object to operate on, and a pointer
+ * to the ObjectWriteOperation to use. All of this must be complete.
+ * @post: all operations are performed and most errors are handled
+ * (e.g., cleans up if an assertion fails). If an unknown error is found,
+ * returns it.
+ */
+ int perform_ops( const std::string &debug_prefix,
+ const index_data &idata,
+ std::vector<std::pair<std::pair<int, std::string>, librados::ObjectWriteOperation*> > * ops);
+
+ /**
+ * Called when a client discovers that another client has died during a
+ * split or a merge. cleans up after that client.
+ *
+ * @param idata: the index data parsed from the index entry left by the dead
+ * client.
+ * @param error: the error that caused the client to realize the other client
+ * died (should be -ENOENT or -ETIMEDOUT)
+ * @post: rolls forward if -ENOENT, otherwise rolls back.
+ */
+ int cleanup(const index_data &idata, const int &error);
+
+ /**
+ * does the ObjectWriteOperation and splits, reads the index, and/or retries
+ * until success.
+ */
+ int set_op(const std::string &key, const bufferlist &val,
+ bool update_on_existing, index_data &idata);
+
+ /**
+ * does the ObjectWriteOperation and merges, reads the index, and/or retries
+ * until success.
+ */
+ int remove_op(const std::string &key, index_data &idata, index_data &next_idata);
+
+ /**
+ * does the ObjectWriteOperation and reads the index and/or retries
+ * until success.
+ */
+ int get_op(const std::string &key, bufferlist * val, index_data &idata);
+
+ /**
+ * does the ObjectWriteOperation and splits, reads the index, and/or retries
+ * until success.
+ */
+ int handle_set_rm_errors(int &err, std::string key, std::string obj,
+ index_data * idata, index_data * next_idata);
+
+ /**
+ * called by aio_set, aio_remove, and aio_get, respectively.
+ */
+ static void* pset(void *ptr);
+ static void* prm(void *ptr);
+ static void* pget(void *ptr);
+public:
+
+
+ //interruption methods, for correctness testing
+ /**
+ * returns 0
+ */
+ int nothing() override;
+ /**
+ * 10% chance of waiting wait_ms seconds
+ */
+ int wait() override;
+ /**
+ * 10% chance of killing the client.
+ */
+ int suicide() override;
+
+KvFlatBtreeAsync(int k_val, std::string name, int cache, double cache_r,
+ bool verb)
+ : k(k_val),
+ index_name("index_object"),
+ rados_id(name),
+ client_name(std::string(name).append(".")),
+ pool_name("rbd"),
+ interrupt(&KeyValueStructure::nothing),
+ wait_ms(0),
+ timeout(100000,0),
+ cache_size(cache),
+ cache_refresh(cache_r),
+ verbose(verb),
+ client_index(0),
+ icache(cache)
+ {}
+
+ /**
+ * creates a string with an int at the end.
+ *
+ * @param s: the string on the left
+ * @param i: the int to be appended to the string
+ * @return the string
+ */
+ static std::string to_string(std::string s, int i);
+
+ /**
+ * returns in encoded
+ */
+ static bufferlist to_bl(const std::string &in) {
+ bufferlist bl;
+ bl.append(in);
+ return bl;
+ }
+
+ /**
+ * returns idata encoded;
+ */
+ static bufferlist to_bl(const index_data &idata) {
+ bufferlist bl;
+ idata.encode(bl);
+ return bl;
+ }
+
+ /**
+ * returns the rados_id of this KvFlatBtreeAsync
+ */
+ std::string get_name();
+
+ /**
+ * sets this kvba to call inject before every ObjectWriteOperation.
+ * If inject is wait and wait_time is set, wait will have a 10% chance of
+ * sleeping for waite_time milliseconds.
+ */
+ void set_inject(injection_t inject, int wait_time) override;
+
+ /**
+ * sets up the rados and io_ctx of this KvFlatBtreeAsync. If the don't already
+ * exist, creates the index and max object.
+ */
+ int setup(int argc, const char** argv) override;
+
+ int set(const std::string &key, const bufferlist &val,
+ bool update_on_existing) override;
+
+ int remove(const std::string &key) override;
+
+ /**
+ * returns true if all of the following are true:
+ *
+ * all objects are accounted for in the index or a prefix
+ * (i.e., no floating objects)
+ * all objects have k <= size <= 2k
+ * all keys in an object are within the specified predicted by the index
+ *
+ * if any of those fails, states that the problem(s) are, and prints str().
+ *
+ * @pre: no operations are in progress
+ */
+ bool is_consistent() override;
+
+ /**
+ * returns an ASCII representation of the index and sub objects, showing
+ * stats about each object and all omaps. Don't use if you have more than
+ * about 10 objects.
+ */
+ std::string str() override;
+
+ int get(const std::string &key, bufferlist *val) override;
+
+ //async versions of these methods
+ void aio_get(const std::string &key, bufferlist *val, callback cb,
+ void *cb_args, int * err) override;
+ void aio_set(const std::string &key, const bufferlist &val, bool exclusive,
+ callback cb, void * cb_args, int * err) override;
+ void aio_remove(const std::string &key, callback cb, void *cb_args, int * err) override;
+
+ //these methods that deal with multiple keys at once are efficient, but make
+ //no guarantees about atomicity!
+
+ /**
+ * Removes all objects and resets the store as if setup had just run. Makes no
+ * attempt to do this safely - make sure this is the only operation running
+ * when it is called!
+ */
+ int remove_all() override;
+
+ /**
+ * This does not add prefixes to the index and therefore DOES NOT guarantee
+ * consistency! It is ONLY safe if there is only one instance at a time.
+ * It follows the same general logic as a rebalance, but
+ * with all objects that contain any of the keys in in_map. It is O(n), where
+ * n is the number of librados objects it has to change. Higher object sizes
+ * (i.e., k values) also decrease the efficiency of this method because it
+ * copies all of the entries in each object it modifies. Writing new objects
+ * is done in parallel.
+ *
+ * This is efficient if:
+ * * other clients are very unlikely to be modifying any of the objects while
+ * this operation is in progress
+ * * The entries in in_map are close together
+ * * It is especially efficient for initially entering lots of entries into
+ * an empty structure.
+ *
+ * It is very inefficient compared to setting one key and/or will starve if:
+ * * other clients are modifying the objects it tries to modify
+ * * The keys are distributed across the range of keys in the store
+ * * there is a small number of keys compared to k
+ */
+ int set_many(const std::map<std::string, bufferlist> &in_map) override;
+
+ int get_all_keys(std::set<std::string> *keys) override;
+ int get_all_keys_and_values(std::map<std::string,bufferlist> *kv_map) override;
+
+};
+
+#endif /* KVFLATBTREEASYNC_H_ */
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-29 23:40:42 +0000