diff --git a/README.md b/README.md index 6209934..02b3e82 100644 --- a/README.md +++ b/README.md @@ -234,6 +234,9 @@ from the `txn` table when `commit()` returned an error is undefined. Return all keys `>= start` and starts with `prefix`. If `db` is omitted, it defaults to `"_default"`. +If `page_size` is specified, up to `page_size` results will be returned. However, +`page_size` can not be set to less than `2` due to internal implementation limitations. + The return value of this function is a table `res` where `res[1].key` and `res[1].value` corresponds to the first key and value, `res[2].key` and `res[2].value` corresponds to the second and etc. If no keys matched the provided criteria, then an empty table will be @@ -246,6 +249,9 @@ matching the `prefix` is available. In case of errors, `nil` and an string describing the reason of the failure will be returned. +This is a low level function, most of the use case should instead use the higher level +[lmdb.prefix](#prefix) iterator instead. + [Back to TOC](#table-of-contents) ## Directives diff --git a/lib/resty/lmdb/prefix.lua b/lib/resty/lmdb/prefix.lua index 84d1f35..989530b 100644 --- a/lib/resty/lmdb/prefix.lua +++ b/lib/resty/lmdb/prefix.lua @@ -31,6 +31,8 @@ function _M.page(start, prefix, db, page_size) page_size = DEFAULT_OPS_SIZE end + assert(page_size >= 2, "'page_size' can not be less than 2") + local value_buf_size = get_string_buf_size() local ops = ffi_new("ngx_lua_resty_lmdb_operation_t[?]", page_size) diff --git a/t/10-prefix.t b/t/10-prefix.t index fa04276..7c942a9 100644 --- a/t/10-prefix.t +++ b/t/10-prefix.t @@ -214,3 +214,114 @@ done [error] [warn] [crit] + + + +=== TEST 6: prefix.page() operation +--- http_config eval: $::HttpConfig +--- main_config eval: $::MainConfig +--- config + location = /t { + content_by_lua_block { + local l = require("resty.lmdb") + + ngx.say(l.db_drop(true)) + ngx.say(l.set("test", "value")) + ngx.say(l.set("test1", "value1")) + ngx.say(l.set("test2", "value2")) + ngx.say(l.set("test3", "value3")) + ngx.say(l.set("u", "value4")) + ngx.say(l.set("u1", "value5")) + + local p = require("resty.lmdb.prefix") + + local res, err = p.page("test", "test") + if not res then + ngx.say("page errored: ", err) + end + + for _, pair in ipairs(res) do + ngx.say("key: ", pair.key, " value: ", pair.value) + end + } + } +--- request +GET /t +--- response_body +true +true +true +true +true +true +true +key: test value: value +key: test1 value: value1 +key: test2 value: value2 +key: test3 value: value3 +--- no_error_log +[error] +[warn] +[crit] + + + +=== TEST 7: prefix.page() operation with custom page size +--- http_config eval: $::HttpConfig +--- main_config eval: $::MainConfig +--- config + location = /t { + content_by_lua_block { + local l = require("resty.lmdb") + + ngx.say(l.db_drop(true)) + ngx.say(l.set("test", "value")) + ngx.say(l.set("test1", "value1")) + ngx.say(l.set("test2", "value2")) + ngx.say(l.set("test3", "value3")) + ngx.say(l.set("u", "value4")) + ngx.say(l.set("u1", "value5")) + + local p = require("resty.lmdb.prefix") + + local res, err = p.page("test", "test", nil, 2) + if not res then + ngx.say("page errored: ", err) + end + + ngx.say("FIRST PAGE") + for _, pair in ipairs(res) do + ngx.say("key: ", pair.key, " value: ", pair.value) + end + + res, err = p.page("test1\x00", "test", nil, 2) + if not res then + ngx.say("page errored: ", err) + end + + ngx.say("SECOND PAGE") + for _, pair in ipairs(res) do + ngx.say("key: ", pair.key, " value: ", pair.value) + end + } + } +--- request +GET /t +--- response_body +true +true +true +true +true +true +true +FIRST PAGE +key: test value: value +key: test1 value: value1 +SECOND PAGE +key: test2 value: value2 +key: test3 value: value3 +--- no_error_log +[error] +[warn] +[crit]